---
title: "Register a client SDK"
method: POST
path: "/api/client/register"
tags: ["Client"]
---

# Register a client SDK

`POST /api/client/register`

Register a client SDK with Unleash. SDKs call this endpoint on startup to tell Unleash about their existence. Used to track custom strategies in use as well as SDK versions.

## Request body

- ClientApplicationSchema — A client application is an instance of one of our SDKs
  - `appName` string, required — An identifier for the app that uses the sdk, should be static across SDK restarts
  - `instanceId` string — A unique identifier identifying the instance of the application running the SDK. Often changes based on execution environment. For instance: two pods in Kubernetes will have two different instanceIds
  - `sdkVersion` string — An SDK version identifier. Usually formatted as "unleash-client-<language>:<version>"
  - `platformName` string — The platform the application is running on. For languages that compile to binaries, this can be omitted
  - `platformVersion` string — The version of the platform the application is running on. Languages that compile to binaries, this is expected to be the compiler version used to assemble the binary.
  - `yggdrasilVersion` string — The semantic version of the Yggdrasil engine used by the client. If the client is using a native engine this can be omitted.
  - `specVersion` string — The version of the Unleash client specification the client supports
  - `sdkFlavor` string — The identifier of an integration built on top of an Unleash SDK (e.g. an OpenFeature provider). Sent so adoption of the integration can be tracked alongside sdkVersion.
  - `sdkFlavorVersion` string — The version of the integration identified by sdk flavor, that has been built on top of an Unleash SDK
  - `interval` number, required — How often (in seconds) does the client refresh its toggles
  - `started` union, required — Either an RFC-3339 timestamp or a unix timestamp in seconds
    - string, date-time
    - number
  - `strategies` string[], required — Which strategies the SDKs runtime knows about

## Response `202`

This response has no body.

---

[API](https://skmtc.net/unleash/apis/unleash-api-2.md) · [All operations](https://skmtc.net/unleash/apis/unleash-api-2/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/unleash/unleash-api-2/revisions/3ead4e02c359/schema)