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Featureflip Client SDK API

Client SDK endpoints for browser-side feature flag evaluation.All endpoints require a valid Client SDK key passed via the Authorization header.Unlike server SDK endpoints, these evaluate flags server-side and return only values.

Featureflip Client SDK API is one of 10 APIs that Featureflip publishes on the APIs.io network, described by a machine-readable OpenAPI specification.

Tagged areas include Client SDK. The published artifact set on APIs.io includes an OpenAPI specification, an API reference, and API documentation.

This API exposes 3 operations across 3 paths, and defines 4 schemas. It is described by OpenAPI 3.2.0, at version v1.

Requests are made against a single base URL, https://eval.featureflip.io.

3 operations 3 paths 4 schemas 1 GET2 POST

Metadata

The identity and technical contract details declared by the specification.

Specification
OpenAPI 3.2.0
API Version
v1
Base URL
https://api.featureflip.io
Authentication
API Key
Resource Areas
1

Authentication & Security 1

Featureflip Client SDK API declares 1 security scheme for authenticating requests. An API key is passed in the header as Authorization (Bearer). By default, every request must be authenticated.

  • Bearer — SDK Key authorization. Enter your SDK key.

Paths & Operations 3

Across 3 paths, the API surfaces 3 operations — 1 GET, 2 POST. Each is listed below with its method, path, parameters, and response codes.

Client SDK 3

Client SDK endpoints for browser-side feature flag evaluation. All endpoints require a valid Client SDK key passed via the Authorization header. Unlike server SDK endpoints, these…

POST
/v1/client/evaluate
Evaluates all client-visible feature flags for the given user context
postV1ClientEvaluate body → 200401503
POST
/v1/client/identify
Re-identifies the user with a new context, for example after login
postV1ClientIdentify body → 200401503
GET
/v1/client/stream
Opens a Server-Sent Events stream for real-time client flag updates
getV1ClientStream 1 param → 200401503

Schemas 4

The contract defines 4 schemas that model the data the API accepts and returns. The most detailed are ProblemDetails (5 properties), ClientFlagValue (4 properties), ClientEvaluateRequest (1 property), ClientEvaluateResponse (1 property). Each schema is shown below with its type and property counts.

ClientEvaluateResponse
object
1 property 1 required
ClientFlagValue
object
4 properties 3 required
ProblemDetails
object
5 properties
ClientEvaluateRequest
object
1 property 1 required

Specification

The full machine-readable OpenAPI contract behind this narrative.

Source

featureflip-client-sdk-api-openapi.yml Raw ↑

Other APIs Featureflip publishes across the network.

MCP Server (local)
Featureflip Environments API
Featureflip Feature Flags API
Featureflip Me API
Featureflip Organizations API
Featureflip Projects API
Featureflip SDK Keys API
Featureflip Server SDK API
Featureflip User Segments API
Where this information came from

This is an independent, third-party profile of Featureflip Client SDK API, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.

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