---
title: "Register signing secret for HMAC verification"
method: POST
path: "/api/v1/telemetry/register"
tags: ["On-Prem Telemetry"]
---

# Register signing secret for HMAC verification

`POST /api/v1/telemetry/register`

Register an on-prem signing secret (`opm_xxx`) for HMAC verification.

    Call once before sending telemetry (optional — the first batch auto-
    registers). The secret is encrypted at rest. `cmp_` API keys are rejected;
    mint an `opm_` credential in the dashboard under Settings -> On-Prem.

    **Required Headers:**
    - `X-API-Key`: Your Compresr API key

    **Body:**
    - `signing_secret`: On-prem signing secret (`opm_xxx`)
    - `instance_id`: Optional instance identifier

## Headers

- `X-API-Key` string, required

## Request body

- RegisterSigningSecretRequest
  - `signing_secret` string, required — On-prem signing secret (opm_xxx). Mint via dashboard -> Settings -> On-Prem. cmp_ API keys are rejected.
  - `instance_id` string, nullable — Instance identifier

## Response `200`

Successful Response

- RegisterSigningSecretResponse
  - `success` boolean, required
  - `message` string, required
  - `user_id` string, nullable

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.net/compresr/apis/compresr-platform-api.md) · [All operations](https://skmtc.net/compresr/apis/compresr-platform-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/compresr/compresr-platform-api/revisions/93ee959dfa51/schema)