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OpenFeature Provider

OpenFeature is an open standard that provides a vendor-agnostic, community-driven API for feature flagging that works with DevCycle.

DevCycle provides a NodeJS implementation of the OpenFeature Provider interface, if you prefer to use the OpenFeature API.

Npm package version GitHub



Install the OpenFeature JS SDK, DevCycle NodeJS Server SDK, and DevCycle NodeJS Provider:

npm install --save @devcycle/openfeature-nodejs-provider @devcycle/nodejs-server-sdk @openfeature/js-sdk

Getting Started

Initialize the DevCycle SDK and set the DevCycleProvider as the provider for OpenFeature:

import { OpenFeature, Client } from '@openfeature/js-sdk'
import { DevCycleProvider } from '@devcycle/openfeature-nodejs-provider'
import { initializeDevCycle } from '@devcycle/nodejs-server-sdk'


// Initialize the DevCycle SDK
const devcycleClient = await initializeDevCycle(DEVCYCLE_SERVER_SDK_KEY).onClientInitialized()
// Set the initialzed DevCycle client as the provider for OpenFeature
OpenFeature.setProvider(new DevCycleProvider(devcycleClient))
// Get the OpenFeature client
openFeatureClient = OpenFeature.getClient()
// Set the context for the OpenFeature client, you can use 'targetingKey' or 'user_id'
openFeatureClient.setContext({ targetingKey: 'node_sdk_test' })

// Retrieve a boolean flag from the OpenFeature client
const boolFlag = await openFeatureClient.getBooleanValue('boolean-flag', false)

Passing DevCycleOptions to the DevCycleProvider

Ensure that you pass any custom DevCycleOptions set on the DevCycleClient instance to the DevCycleProvider constructor

const options = { logger: dvcDefaultLogger({ level: 'debug' }) }
const devcycleClient = await initializeDevCycle(DEVCYCLE_SERVER_SDK_KEY, options).onClientInitialized()
OpenFeature.setProvider(new DevCycleProvider(devcycleClient, options))

Required TargetingKey

For DevCycle SDK to work we require either a targetingKey or user_id to be set on the OpenFeature context. This is used to identify the user as the user_id for a DevCycleUser in DevCycle.

Context properties to DevCycleUser

The provider will automatically translate known DevCycleUser properties from the OpenFeature context to the DevCycleUser object. DevCycleUser TypeScript Interface

For example all these properties will be set on the DevCycleUser:

user_id: 'user_id',
email: '[email protected]',
name: 'name',
language: 'en',
country: 'CA',
appVersion: '1.0.11',
appBuild: 1000,
customData: { custom: 'data' },
privateCustomData: { private: 'data' }

Context properties that are not known DevCycleUser properties will be automatically added to the customData property of the DevCycleUser.

Context Limitations

DevCycle only supports flat JSON Object properties used in the Context. Non-flat properties will be ignored.

For example obj will be ignored:

user_id: 'user_id',
obj: { key: 'value' }

JSON Flag Limitations

The OpenFeature spec for JSON flags allows for any type of valid JSON value to be set as the flag value.

For example the following are all valid default value types to use with OpenFeature:

// Invalid JSON values for the DevCycle SDK, will return defaults
openFeatureClient.getObjectValue('json-flag', ['arry'])
openFeatureClient.getObjectValue('json-flag', 610)
openFeatureClient.getObjectValue('json-flag', false)
openFeatureClient.getObjectValue('json-flag', 'string')
openFeatureClient.getObjectValue('json-flag', null)

However, these are not valid types for the DevCycle SDK, the DevCycle SDK only supports JSON Objects:

// Valid JSON Object as the default value, will be evaluated by the DevCycle SDK
openFeatureClient.getObjectValue('json-flag', { default: 'value' })