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User and context configuration

Read time: 39 minutes
Last edited: May 30, 2024

Overview

This topic explains how to configure user and context objects in LaunchDarkly SDKs. These features are available for both client-side and server-side SDKs.

Newer versions of LaunchDarkly SDKs replace users with contexts

A context is a generalized way of referring to the people, services, machines, or other resources that encounter feature flags in your product. Contexts replace another data object in LaunchDarkly: "users." To learn more, read Contexts.

Creating contexts and evaluating flags based on them is supported in the latest major versions of most of our SDKs. For these SDKs, the code samples on this page include the two most recent versions.

Configuration for context objects

Every LaunchDarkly SDK lets you configure context or user objects to return specific data to LaunchDarkly. Any attributes you pass to LaunchDarkly become available on the Contexts list. The attribute values determine which variation of a feature flag the customer receives.

Here is an image of the Contexts list:

The "Contexts" list.
The "Contexts" list.

Every object is required to have a key. Keys are always transmitted to LaunchDarkly. Typically, you supply the key when you create the context. If you are using a client-side SDK and mark the context as anonymous, the SDK can generate the key for you. To learn more, read Anonymous contexts and users.

Keys must be a string type. Keys must be unique, deterministic, and should not contain personally identifiable information (PII). Keys must be consistent, which means the same person must correspond to the same key across different services to contribute to consistent flag evaluations. You can use a primary key or a hash, as long as the same person always has the same key. We recommend using a hash if possible.

Only the context attributes you provide are available for targeting

The SDK only evaluates flags based on the context you configure and then provide in the evaluation call. The SDK does not use the attributes shown on the Contexts list, and context attributes are not synchronized across SDK instances. You must provide all applicable attributes for each evaluation in the SDK for your targeting rules to apply correctly.

About built-in and custom attributes

Attributes other than the key are optional. There are two types of attributes: built-in attributes, which are LaunchDarkly names, and custom attributes, which you can name anything you choose.

When you work with an SDK that supports contexts, the only built-in attributes are kind, key, name, and anonymous.

You can define additional attributes for a context by passing in a name and value for each. These additional attributes let you add targeting rules for your flags based on any data that you want to send to LaunchDarkly. Attribute values can be any JSON type, including boolean, number, string, array, or object. To learn more, read Context attributes.

Custom and built-in attributes cannot share names

If you create an attribute with a name already in use by a built-in attribute, the SDK will behave unpredictably during feature flag evaluation.

When you work with an SDK that supports contexts, the only built-in attributes are kind, key, name, and anonymous. If you work with an SDK that only supports users, there are several additional built-in attributes.

To learn how to configure private attributes in your SDK, read Private attributes.

Details about each SDK's configuration are available in the SDK-specific sections below.

  • Client-side SDKs
  • Server-side SDKs
  • Edge SDKs

Client-side SDKs

Here are the configuration options for context and user entities in client-side SDKs.

.NET (client-side)

Expand .NET (client-side) code sample

In the client-side .NET SDK, you can construct a simple Context, with a context kind of "user," that only has a key by calling Context.New. Alternatively, you can use Context.Builder, which allows setting all properties.

Here's an example:

Context context = Context.Builder("context-key-123abc")
.Set("firstName", "Sandy")
.Set("lastName", "Smith")
.Set("email", "sandy@example.com")
.Set("group", "microsoft")
.Build();

The argument to Builder is the context's key. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "context-key-123abc".

Interpreting custom attribute types

The optional name and kind attributes, which you can set with .Name() and .Kind(), expect string values. If the kind attribute is not specified, it is assumed to be "user." Other attribute values can be any JSON type, including booleans, numbers, strings, arrays, or objects. The SDK uses the LdValue type to represent arrays and objects. The client-side .NET SDK is strongly-typed, so be aware of this distinction.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a context with a context kind of something other than "user":

var context = Context.New(ContextKind.Of("organization"), "org-key-123abc");

Here's how to construct a multi-context, which includes multiple context kinds:

var userContext = Context.New("user-key-123abc");
var orgContext = Context.New(ContextKind.Of("organization"), "org-key-123abc");
var multiContext = Context.NewMulti(userContext, orgContext);

To learn how to configure private attributes in the .NET (client-side) SDK, read Private attributes.

To learn how to configure anonymous contexts in the .NET (client-side) SDK, read Anonymous contexts and users.

Android

Expand Android code sample

In the Android SDK, use a builder pattern to construct contexts.

Here's an example:

LDContext context = LDContext.builder("context-key-123abc")
.set("email", "sandy@example.com")
.set("firstName", "Sandy")
.set("lastName", "Smith")
.set("group", "Microsoft")
.build();

The argument to Builder is the context's key. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "context-key-123abc".

Interpreting custom attribute types

The optional name and kind attributes, which you can set with .name() and .kind(), expect string values. If the kind attribute is not specified, it is assumed to be "user." Other attribute values can be any JSON type, including boolean, number, string, array, or object. The Android SDK is strongly-typed, so be aware of this distinction.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

LDContext context1 = LDContext.create(ContextKind.of("organization"), "org-key-123abc");

Here's how to construct a multi-context, which includes multiple context kinds:

LDContext multiContext = LDContext.createMulti(
LDContext.create("user-key-123abc"),
LDContext.create(ContextKind.of("device"), "device-key-123abc")
);

To learn how to configure private attributes in the Android SDK, read Private attributes.

To learn how to configure anonymous contexts in the Android SDK, read Anonymous contexts and users.

LDUser removal

Version 4 of the Android SDK replaced users with contexts. Starting in version 5, the deprecated LDUser is removed. To learn more about replacing users with contexts, read the Android SDK 3.x to 4.0 migration guide and Best practices for upgrading users to contexts.

C++ (client-side)

Expand C++ (client-side) code sample

In the C++ (client-side) SDK, you can construct a context using the ContextBuilder.

Here's an example:

auto context = ContextBuilder()
.Kind("user", "user-key-123abc")
.Set("firstName", "Sandy")
.Set("lastName", "Smith")
.Set("groups", {"Google", "Microsoft"})
.Build();

The arguments to .Kind() are the context kind and key. Together these must uniquely identify each context. You can use a primary key, an email address, or a hash for the key, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

Interpreting custom attribute types

The name and kind attributes, which you can set with .Name() and .Kind(), expect string values. Other attribute values can be any JSON type, including boolean, number, string, array, or object.

You can also construct a context that includes multiple kinds. Here's how:

auto context = ContextBuilder()
.Kind("user", "user-key-123abc")
.Name("Sandy")
.Kind("organization", "org-key-123abc")
.Name("Global Health Services")
.Build();

To learn how to configure private attributes in the C++ (client-side) SDK, read Private attributes.

To learn how to configure anonymous users in the C++ (client-side) SDK, read Anonymous contexts and users.

Electron

Expand Electron code sample
Personally-identifying user keys

By default, when the SDK requests feature flags from LaunchDarkly, it makes an HTTP GET request with the user properties encoded in the URL. If you do not want user keys or other properties to be in request URLs, enable the useReport option in your client configuration. The SDK sends user data in the body of an HTTP REPORT request instead.

Here's an example of a user:

const user = {
key: 'user-key-123abc',
firstName: 'Sandy',
lastName: 'Smith',
email: 'sandy@example.com',
custom: {
groups: ['Google', 'Microsoft']
}
};

The key property is the user's key. The key should uniquely identify each user. You can use a primary key or a hash, as long as the same user always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

Interpreting custom attribute types

Most of the built-in attributes, like names and email addresses, expect string values. Custom attribute values can be booleans, numbers, strings, or arrays. If you enter a custom value on the Users list that looks like a number or a boolean, the SDK interprets it that way.

To learn how to configure private attributes in the Electron SDK, read Private attributes.

To learn how to configure anonymous users in the Electron SDK, read Anonymous contexts and users.

Flutter

Expand Flutter code sample

In the Flutter SDK, use a builder pattern to construct contexts.

Here's an example:

final context = LDContextBuilder()
.kind('user', 'user-key-123abc')
.setString('email', 'sandy@example.com')
.setString('firstName', 'Sandy')
.setString('lastName', 'Smith')
.setString('group', 'microsoft')
.build();

The arguments to LDContextBuilder are the context's kind and key. This combination must uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

Interpreting custom attribute types

The required kind and optional name attributes expect string values. Other attribute values can be any JSON type, including boolean, number, string, array, or object. Attribute values in the Flutter SDK use the LDValue class to support the various underlying types for the values. The Flutter SDK is strongly-typed, so be aware of this distinction.

Starting in version 4, the Flutter SDK provides setters so that you do not have to create an LDValue yourself. Instead, you can use setBool, setNum, and setString when adding attributes to a context.

To learn how to configure private attributes in the Flutter SDK, read Private attributes.

To learn how to configure anonymous users in the Flutter SDK, read Anonymous contexts and users.

iOS

Expand iOS code sample

You can pass optional properties to the context object in iOS:

var contextBuilder = LDContextBuilder(key: "context-key-123abc")
contextBuilder.trySetValue("name", .string("Sandy"))
contextBuilder.trySetValue("email", .string("sandy@example.com"))
let context = try contextBuilder.build().get()

This example sets a key and adds the end user's full name and email address.

The key property should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "context-key-123abc".

You can define additional attributes for a context by passing in a name and value for each. Additional attributes can be any JSON type, including boolean, number, string, array, or object.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

To learn more about the specific context properties that are available in this SDK, read LDContextBuilder.

Here's how to construct a multi-context, which includes multiple context kinds:

var userBuilder = LDContextBuilder(key: "user-key-123abc")
var deviceBuilder = LDContextBuilder(key: "device-key-123abc")
deviceBuilder.kind("device")
var multiBuilder = LDMultiContextBuilder()
multiBuilder.addContext(try userBuilder.build().get())
multiBuilder.addContext(try deviceBuilder.build().get())
let context = try multiBuilder.build().get()

To learn how to configure private attributes in the iOS SDK, read Private attributes.

To learn how to configure anonymous contexts in the iOS SDK, read Anonymous contexts and users.

LDUser removal

Version 8 of the iOS SDK replaced users with contexts. Starting in version 9, the deprecated LDUser is removed. To learn more about replacing users with contexts, read the iOS SDK 7.x to 8.0 migration guides for Swift or Objective-C and Best practices for upgrading users to contexts.

JavaScript

Expand JavaScript code sample

Here's an example of a context:

const context = {
kind: 'user',
key: 'user-key-123abc',
firstName: 'Sandy',
lastName: 'Smith',
email: 'sandy@example.com',
groups: ['Google', 'Microsoft']
};

The key property should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is user-key-123abc.

Interpreting custom attribute types

The optional name and kind attributes expect string values. If the kind attribute is not specified, it is assumed to be "user." Other attributes can be booleans, numbers, strings, arrays, or JSON objects.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Personally-identifying context keys

We recommend against using personally identifiable information (PII) in context keys. If the key attribute you rely on in your context JSON does contain PII, you should enable the useReport option by sending the evaluation context as a JSON base64 URL-encoded path parameter. When you enable useReport, the SDK fetches flag settings by sending the context JSON in the body of a REPORT request instead, hiding that information from request logs.

Here's how to construct a basic context with a context kind of something other than "user":

const context = {
kind: 'organization',
key: 'org-key-123abc'
};
const client = LDClient.initialize('client-side-id-123abc', context);

Here's how to construct a multi-context, which includes multiple context kinds:

const deviceContext = {
kind: 'device',
type: 'iPad',
key: 'device-key-123abc'
}
const userContext = {
kind: 'user',
key: 'user-key-123abc',
name: 'Sandy',
role: 'doctor'
}
const multiContext = {
kind: 'multi',
user: userContext,
device: deviceContext
}
const client = LDClient.initialize('client-side-id-123abc', multiContext)

To learn how to configure private attributes in the JavaScript SDK, read Private attributes.

To learn how to configure anonymous contexts in the JavaScript SDK, read Anonymous contexts and users.

Node.js (client-side)

Expand Node.js (client-side) code sample

Here's an example of a context:

const context = {
kind: 'user',
key: 'user-key-123abc',
firstName: 'Sandy',
lastName: 'Smith',
email: 'sandy@example.com',
groups: ['Google', 'Microsoft']
};

The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

The kind and name attributes expect string values. Other attribute values can be booleans, numbers, strings, arrays, or JSON objects.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Personally-identifying user keys

By default, when the SDK requests feature flags from LaunchDarkly, it makes an HTTP GET request with the user properties encoded in the URL. If you do not want user keys or other properties to be in request URLs, enable the useReport option in your client configuration. The SDK sends user data in the body of an HTTP REPORT request instead.

Here's how to construct a basic context with a context kind of something other than "user":

const context = {
kind: 'organization',
key: 'org-key-123abc'
};
const client = LaunchDarkly.initialize('client-side-id-123abc', context);

Here's how to construct a multi-context, which includes multiple context kinds:

const deviceContext = {
kind: 'device',
type: 'iPad',
key: 'device-key-123abc'
}
const userContext = {
kind: 'user',
key: 'user-key-123abc',
name: 'Sandy',
role: 'doctor'
}
const multiContext = {
kind: 'multi',
user: userContext,
device: deviceContext
}
const client = LaunchDarkly.initialize('client-side-id-123abc', multiContext)

To learn how to configure private attributes in the Node.js (client-side) SDK, read Private attributes.

To learn how to configure anonymous contexts in the Node.js (client-side) SDK, read Anonymous contexts and users.

React Native

Expand React Native code sample

Here is a context configuration object:

import { type LDContext } '@launchdarkly/react-native-client-sdk';
// key and kind are the only required attributes
let context: LDContext = {
key: 'user-key-123abc',
kind: 'user',
firstName: 'Sandy',
lastName: 'Smith',
email: 'sandy@example.com',
address: {
street: '123 Main St',
city: 'Springfield'
}
};

The first attribute in the object is the key. In the React Native SDK, both key and kind are required. They are the only mandatory attributes. The combination of key and kind should uniquely identify each context. You can use any value for the key, such as a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the value is user-key-123abc.

If the context is anonymous, you should set the key to an empty string. The SDK will automatically set the key to a LaunchDarkly-specific, device-unique string that is consistent between app restarts and device reboots.

Other attributes can be booleans, numbers, strings, arrays, or JSON objects.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

const context = {
kind: 'organization',
key: 'org-key-123abc'
};

Here's how to construct a multi-context, which includes multiple context kinds:

const deviceContext = {
kind: 'device',
key: 'device-key-123abc'
};
const userContext = {
kind: 'user',
key: 'user-key-123abc',
name: 'Sandy',
role: 'doctor'
};
const multiContext = {
kind: 'multi',
user: userContext,
device: deviceContext
}

To learn how to configure private attributes in the React Native SDK, read Private attributes.

To learn how to configure anonymous contexts in the React Native SDK, read Anonymous contexts and users.

React Web

All context-related functionality provided by the JavaScript SDK is also available in the React Web SDK.

Unlike the JavaScript SDK, the React Web SDK does not require a context object for initialization. If you do not specify one, the React SDK uses an anonymous context by default.

Roku

Expand Roku code sample

You can create a context object with:

context = LaunchDarklyCreateContext({"key": "user-key-123abc", "kind": "user"})

The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

Interpreting custom attribute types

The optional name and kind attributes expect string values. If the kind attribute is not specified, it is assumed to be "user." Other attributes can be booleans, numbers, strings, arrays, or JSON objects.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

To learn how to configure private attributes in the Roku SDK, read Private attributes.

To learn how to configure anonymous contexts in the Roku SDK, read Anonymous contexts and users.

Server-side SDKs

Here are the configuration options for context and user entities in server-side SDKs:

.NET (server-side)

Expand .NET (server-side) code sample

In the .NET SDK, the Context class has a New method for creating a simple context, with a context kind of "user" and with only a key. It has a Builder method for building a context with other properties.

Here's an example:

LDContext context = Context.Builder("context-key-123abc")
.Set("firstName", "Sandy")
.Set("lastName", "Smith")
.Set("email", "sandy@example.com")
.Set("groups", LdValue.ArrayOf(LdValue.Of("Google"), LdValue.Of("Microsoft")))
.Build();

The argument to Builder is the context's key. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is context-key-123abc.

Interpreting custom attribute types

The optional name and kind attributes, which you can set with .Name() and .Kind(), expect string values. If the kind attribute is not specified, it is assumed to be "user." Other attribute values can be booleans, numbers, strings, arrays, or JSON objects. The SDK uses the LdValue type to represent arrays and objects. The .NET SDK is strongly-typed, so be aware of this distinction.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

var context2 = Context.New(ContextKind.Of("organization"), "org-key-123abc");

Here's how to construct a multi-context, which includes multiple context kinds:

var userContext = Context.New("context-key-123abc");
var deviceContext = Context.Builder("device-key-123abc")
.Kind("device")
.Build();
var multiContext = Context.NewMulti(userContext, deviceContext);

To learn how to configure private attributes in the .NET (server-side) SDK, read Private attributes.

To learn how to configure anonymous contexts in the .NET (server-side) SDK, read Anonymous contexts and users.

Apex

Expand Apex code sample

Here's an example of a user:

LDUser user = new LDUser.Builder('user-key-123abc')
.setFirstName('Sandy')
.setLastName('Smith')
.setEmail('sandy@example.com')
.setCustom(new LDValueObject.Builder()
.set('groups', new LDValueArray.Builder()
.add(LDValue.of('Google'))
.add(LDValue.of('Microsoft'))
.build()
)
.build()
)
.build();

The argument to Builder is the user's key. The key should uniquely identify each user. You can use a primary key or a hash, as long as the same user always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

To learn how to configure private attributes in the Apex SDK, read Private attributes.

To learn how to configure anonymous users in the Apex SDK, read Anonymous contexts and users.

C++ (server-side)

Expand C++ (server-side) code sample

In the C++ (server-side) SDK, you can construct a context using the ContextBuilder.

Here's an example:

auto context = ContextBuilder()
.Kind("user", "user-key-123abc")
.Set("firstName", "Sandy")
.Set("lastName", "Smith")
.Set("groups", {"Google", "Microsoft"})
.Build();

The arguments to .Kind() are the context kind and key. Together these must uniquely identify each context. You can use a primary key or a hash for the key, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

You can also construct a context that includes multiple kinds. Here's how:

auto context = ContextBuilder()
.Kind("user", "user-key-123abc")
.Name("Sandy")
.Kind("organization", "org-key-123abc")
.Name("Global Health Services")
.Build();

If you are working in C, when you are done with the context ensure that you free the structure:

LDContext_Free(context);

To learn how to configure private attributes in the C++ (server-side) SDK, read Private attributes.

To learn how to configure anonymous users in the C++ (server-side) SDK, read Anonymous contexts and users.

Erlang

Expand Erlang code sample

Here's an example of a context:

Context = ldclient_context:set(<<"name">>, <<"Sandy Smith">>,
ldclient_context:set(<<"email">>, <<"sandy@example.com">>,
ldclient_context:set(<<"group">>, [<<"microsoft">>, <<"google">>],
ldclient_context:new(<<"user-key-abc123">>, <<"user">>)))),

The key property is the context's key. The key is the only mandatory context attribute. The combination of key and kind should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

You can set the kind, or, if you do not set it, LaunchDarkly assumes that the context kind is "user."

Here's how to construct a basic context with a context kind of something other than "user":

Context = ldclient_context:new(<<"org-key-123abc">>, <<"organization">>)
%% Or as a map
Context = #{kind => <<"organization">>, key => <<"org-key-123abc">>}

Here's how to construct a multi-context, which includes multiple context kinds:

Context = ldclient_context:new_multi_from([
%% Using `new/1` creates a context with a kind of <<"user">>.
ldclient_context:new(<<"user-key-123abc">>),
%% Using `new/2` creates a context of the specified kind (<<"device">>).
ldclient_context:new(<<"device-key-123abc">>, <<"device">>)]). %% kind = device

To learn how to configure private attributes in the Erlang SDK, read Private attributes.

To learn how to configure anonymous contexts in the Erlang SDK, read Anonymous contexts and users.

Go

Expand Go code sample

The Go SDK defines a Context struct and a Builder.

Here's an example:

import (
"github.com/launchdarkly/go-sdk-common/v3/ldcontext"
"github.com/launchdarkly/go-sdk-common/v3/ldvalue"
)
// Context with only a key
// by default, the context kind is "user"
context1 := ldcontext.New("context-key-123abc")
// Context with a key plus other attributes
context2 := ldcontext.NewBuilder("context-key-456def").
Kind("organization").
Name("Global Health Services").
SetString("email", "info@globalhealthexample.com").
SetValue("address", ldvalue.ObjectBuild().
SetString("street", "123 Main Street").
SetString("city", "Springfield")).
SetValue("groups", ldvalue.ArrayOf(
ldvalue.String("Google"), ldvalue.String("Microsoft"))).
Build()

The most common attribute is the context's key. The key is the only mandatory context attribute. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this case, the key and hash are "context-key-123abc" and "context-key-456def".

To learn more about the available attributes, read Context and Builder.

Interpreting attribute types

The kind and name attributes expect string values. You can set the kind, or, if you do not set it, LaunchDarkly assumes that the context kind is "user." Other attribute values can be booleans, numbers, strings, arrays, or JSON objects. These types are all represented by the ldvalue.Value type. The Go SDK is strongly-typed, so be aware of this distinction.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

context1 := ldcontext.NewWithKind("organization", "org-key-123abc")

Here's how to construct a multi-context, which includes multiple context kinds:

multiContext := ldcontext.NewMulti(
ldcontext.New("user-key-123abc"),
ldcontext.NewWithKind("device", "device-key-123abc")
)

Each individual context within a multi-context can have the same attributes as a basic context. The only restriction is that each context has to have a different context kind from the others within the multi-context.

You can also use the context builder to create each of the individual contexts:

multiContext := ldcontext.NewMulti(
ldcontext.NewBuilder("user-key-123abc").Name("Sandy").Build(),
ldcontext.NewBuilder("device-key-123abc").Kind("device").Name("iPad").Build(),
)

To learn how to configure private attributes in the Go SDK, read Private attributes.

To learn how to configure anonymous contexts in the Go SDK, read Anonymous contexts and users.

Haskell

Expand Haskell code sample

Here's an example of a context:

{-# LANGUAGE OverloadedStrings #-}
import LaunchDarkly.Server.Context
import Data.Function ((&))
-- Context with key and kind
context1 :: Context
context1 = makeContext "context-key-123abc" "user"
-- Context with a key plus other attributes
context2 :: Context
context2 = makeContext "context-key-456def" "organization"
& withAttribute "name" "Global Health Services"
& withAttribute "email" "info@globalhealthexample.com"
& withAttribute "address" $ Object $ fromList [("street", "123 Main St"), ("city", "Springfield")]

The argument to makeUser is the context's key. The key is the only mandatory attribute. The combination of the key and kind should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

Here's how to construct a basic context with a context kind of something other than "user":

makeContext "context-key-123abc" "organization"

Here's how to construct a multi-context, which includes multiple context kinds:

makeMultiContext [ makeContext "user-key-123abc" "user"
, makeContext "device-key-123abc" "device"
]

To learn how to configure private attributes in the Haskell SDK, read Private attributes.

To learn how to configure anonymous contexts in the Haskell SDK, read Anonymous contexts and users.

Java

Expand Java code sample

In the Java SDK, use a builder pattern to construct contexts.

Here's an example:

LDContext context = LDContext.builder("context-key-123abc")
.set("firstName", "Sandy")
.set("lastName", "Smith")
.set("email", "sandy@example.com")
.set("groups",
LDValue.buildArray().add("Google").add("Microsoft").build())
.build();

The argument to Builder is the context's key. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "context-key-123abc".

The documentation for ContextBuilder shows you all the attributes that LaunchDarkly supports by default.

Interpreting custom attribute types

The optional name and kind attributes expect string values. If the "kind" attribute is not specified, it is assumed to be "user." Other attribute values can be booleans, numbers, strings, arrays, or objects. If you pass a value that looks like a number or a boolean, the SDK interprets it that way. The Java SDK is strongly-typed, so be aware of this distinction.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

LDContext context1 = LDContext.create(ContextKind.of("organization"), "org-key-123abc");

Here's how to construct a multi-context, which includes multiple context kinds:

LDContext multiContext = LDContext.createMulti(
LDContext.create("user-key-123abc"),
LDContext.create(ContextKind.of("device"), "device-key-123abc")
);

To learn how to configure private attributes in the Java SDK, read Private attributes.

To learn how to configure anonymous contexts in the Java SDK, read Anonymous contexts and users.

Lua

Expand Lua code sample

In the Lua SDK, use makeContext to construct a context of any kind. This requires a unique context key. The context attributes are defined as part of the context kind.

To construct a user context specifically, you can use makeUser. This requires a unique context key. You can omit the kind option if you construct your context with makeUser. This method is a convenience to make upgrading from the Lua SDK version 1.x to version 2.0 easier. It is deprecated and may be removed in future versions.

Here's an example of a context:

-- using makeContext
local user1 = ld.makeContext({
user = {
key = "user1-key-123abc",
attributes = {
firstName = "Sandy",
lastName = "Smith",
email = "sandy@example.com",
groups = { "Google", "Microsoft" }
}
}
})
-- using makeUser, which is deprecated,
-- to create an identical context (with unique key)
local user2 = ld.makeUser({
key = "user2-key-123abc",
firstName = "Sandy",
lastName = "Smith",
email = "sandy@example.com",
custom = {
groups = { "Google", "Microsoft" }
}
})
-- using makeContext to create a different kind of context
local orgContext = ld.makeContext({
organization = {
key = "org-key-123abc",
name = "Global Health Services"
}
})

Both makeUser and makeContext require a context key. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user1-key-123abc".

To learn more, read makeUser and makeContext.

To learn how to configure private attributes in the Lua SDK, read Private attributes.

To learn how to configure anonymous contexts in the Lua SDK, read Anonymous contexts and users.

Node.js (server-side)

Expand Node.js (server-side) code sample

In the Node.js SDK, contexts are JSON objects.

Here's an example:

const ld = require('@launchdarkly/node-server-sdk');
const context: ld.LDContext = {
kind: 'user',
key: 'user-key-123abc',
firstName: 'Sandy',
lastName: 'Smith',
email: 'sandy@example.com',
groups: ['Google', 'Microsoft'],
};

The key property is the context key. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "user-key-123abc".

Interpreting custom attribute types

The optional name and kind attributes expect string values. If the kind attribute is not specified, it is assumed to be "user." Other attribute values can be booleans, numbers, strings, arrays, or JSON objects.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

const context = {
kind: 'device',
key: 'device-key-123abc'
}

Here's how to construct a multi-context, which includes multiple context kinds:

const context = {
kind: 'multi',
user: { key: 'user-key-123abc' },
device: { key: 'device-key-123abc' }
}

To learn how to configure private attributes in the Node.js (server-side) SDK, read Private attributes.

To learn how to configure anonymous contexts in the Node.js (server-side) SDK, read Anonymous contexts and users.

PHP

Expand PHP code sample

In the PHP SDK, use a builder pattern to construct contexts.

Here's an example:

$context = LDContext::builder("context-key-123abc")
->set("firstName", "Sandy")
->set("lastName", "Smith")
->set("email", "sandy@example.com")
->set("groups", ["Google", "Microsoft"])
->build();

The first argument to LDContextBuilder is the context's key. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "context-key-123abc".

Interpreting custom attribute types

The kind and name attributes expect string values. Other attribute values can be booleans, numbers, strings, or arrays. If you enter a custom value on the Contexts list that looks like a number or a boolean, the SDK interprets it that way. The PHP SDK is strongly-typed, so be aware of this distinction.

Here's how to construct a basic context with a context kind of something other than "user":

$context = LDContext::create("context-key-123abc", "organization");

Here's how to construct a multi-context, which includes multiple context kinds:

$deviceContext = LDContext::create("device-key-123abc", "device");
$orgContext = LDContext::create("org-key-123abc", "org");
$multiContext = LDContext::createMulti($deviceContext, $orgContext);

To learn how to configure private attributes in the PHP SDK, read Private attributes.

To learn how to configure anonymous contexts in the PHP SDK, read Anonymous contexts and users.

Python

Expand Python code sample

In version 8.0 and higher of the Python SDK, the Context class has a create method for creating a simple context, with a context kind of "user" and with only a key. It has a builder method for building a context with other properties.

Here's an example:

context = Context.builder("context-key-123abc") \
.set("firstName", "Sandy") \
.set("lastName", "Smith") \
.set("email", "sandy@example.com") \
.set("groups", ["Google", "Microsoft"]) \
.build()

The argument to Context.builder is the context's key. The key should uniquely identify each context. You can use a primary key or a hash, as long as the same context always has the same key. We recommend using a hash if possible. In this example, the hash is "context-key-123abc".

Interpreting custom attribute types

The optional name and kind attributes expect string values. If the "kind" attribute is not specified, it is assumed to be "user." Other attribute values can be booleans, numbers, strings, arrays, or objects.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

context1 = Context.create("org-key-123abc", "organization")

Here's how to construct a multi-context, which includes multiple context kinds:

multi_context = Context.create_multi(
Context.create("user-key-123abc"),
Context.create("device-key-123abc", "device")
)

If you have many attributes to set, you can also create a context from a dictionary:

pre_existing_dict = {
'key': 'context-key-123abc',
'kind': 'user',
'firstName': 'Sandy',
'lastName': 'Smith',
'email': 'sandy@example.com',
'groups': ['Google', 'Microsoft'],
}
context = Context.from_dict(pre_existing_dict)

To learn more, read from_dict.

To learn how to configure private attributes in the Python SDK, read Private attributes.

To learn how to configure anonymous contexts in the Python SDK, read Anonymous contexts and users.

Ruby

Expand Ruby code sample

In the Ruby SDK, contexts are instances of LaunchDarkly::LDContext. Legacy users can continue to be provided as simple hashes.

Here's an example:

context = LaunchDarkly::LDContext.create({
key: "user-key-123abc",
kind: "user",
firstName: "Sandy",
lastName: "Smith",
email: "sandy@example.com",
groups: ["Google", "Microsoft"]
})

The key property is the context's key. The key should uniquely identify each context. You can use a primary key, an email address, or a hash string, as long as the same context always has the same key. We recommend using a hash string if possible. In this example, the hash is "user-key-123abc".

Context attribute keys must be symbols

All context attribute keys, for both built-in and custom attributes, must be symbols and not strings.

Interpreting custom attribute types

The optional name and kind attributes expect string values. If the "kind" attribute is not specified, it is assumed to be "user" and the hash is assumed to be in the legacy user format. Other attribute values can be booleans, numbers, strings, arrays, or objects. If you enter a custom value on the Contexts list that looks like a number or a boolean, the SDK interprets it that way.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

context = LaunchDarkly::LDContext.with_key("context-key-123abc", "organization")

Here's how to construct a multi-context, which includes multiple context kinds:

multi_context = LaunchDarkly::LDContext.create_multi([
LaunchDarkly::LDContext.with_key("user-key-123abc"),
LaunchDarkly::LDContext.with_key("device-key-123abc", "device"),
])

To learn how to configure private attributes in the Ruby SDK, read Private attributes.

To learn how to configure anonymous contexts in the Ruby SDK, read Anonymous contexts and users.

Rust

Expand Rust code sample

The Rust SDK defines a Context struct and a ContextBuilder.

Here's an example:

// Context with only a key
let context = ContextBuilder::new("context-key-123abc").build()?;
// Context with a key plus other attributes
let custom = hashmap! {
"groups".into() => vec!["Google", "Microsoft"].into(),
};
let context = ContextBuilder::new("context-key-123abc")
.set_value("first_name", "Sandy".into())
.set_value("last_name", "Smith".into())
.set_value("email", "sandy@example.com".into())
.set_value("Google", "groups".into())
.set_value("Microsoft", "groups".into())
.build();

The most common attribute is the context's key. The key is the only mandatory context attribute. The combination of the key and kind should also uniquely identify each context. For the context key, you can use a primary key, a hash string, or some other value, as long as the same context always has the same key. We recommend using a hash string if possible. In this example, the hash is "context-key-123abc".

You can set the kind, or, if you do not set it, LaunchDarkly assumes that the context kind is "user."

To learn more about the available attributes, read Context and ContextBuilder.

Interpreting custom attribute types

The optional name and kind attributes, which you can set with .name() and .kind(), expect string values. Other attribute values can be any JSON type, including booleans, numbers, strings, arrays, or objects. These types are all represented by the AttributeValue type. The Rust SDK is strongly-typed, so be aware of this distinction.

If an attribute is a JSON object, then in your flag or segment targeting, you can use / as a delimiter to refer to specific object fields. For example, if you have an "address" attribute that includes several fields, then you could use /address/city in your targeting. To learn more, read Target with flags.

Here's how to construct a basic context with a context kind of something other than "user":

let context = ContextBuilder::new("context-key-123abc")
.kind("organization")
.build()?;

Here's how to construct a multi-context, which includes multiple context kinds:

let user_context = ContextBuilder::new("user-key-123abc").build()?;
client.identify(user_context.clone());
let device_context = ContextBuilder::new("device-key-123abc").kind("device").build()?;
client.identify(device_context.clone());
let multi_context = MultiContextBuilder::new()
.add_context(user_context)
.add_context(device_context)
.build()?;
client.identify(multi_context);

To learn how to configure private attributes in the Rust SDK, read Private attributes.

To learn how to configure anonymous contexts in the Rust SDK, read Anonymous contexts and users.

Edge SDKs

Here are the configuration options for context and user entities in edge SDKs.

Akamai

Expand Akamai code sample

To configure contexts, the Akamai SDK uses the same code as the Node.js server-side SDK.

The Akamai SDK does not support sending events, so private attributes are not supported.

Cloudflare

Expand Cloudflare code sample

To configure contexts, the Cloudflare SDK uses the same code as the Node.js server-side SDK.

The Cloudflare SDK does not support sending events, so private attributes are not supported.

Vercel

Expand Vercel code sample

To configure contexts, the Vercel SDK uses the same code as the Node.js server-side SDK.

The Vercel SDK does not support sending events, so private attributes are not supported.