---
title: "Create Message Precheck"
method: POST
path: "/api/v1/app/{app_id}/msg/precheck/active"
tags: ["Message"]
---

# Create Message Precheck

`POST /api/v1/app/{app_id}/msg/precheck/active`

A pre-check call for `message.create` that checks whether any active endpoints are
listening to this message.

Note: most people shouldn't be using this API. Svix doesn't bill you for
messages not actually sent, so using this API doesn't save money.
If unsure, please ask Svix support before using this API.

## Path parameters

- `app_id` string, required — The Application's ID or UID.

## Headers

- `idempotency-key` string

## Request body

- MessagePrecheckIn
  - `channels` string[], nullable
  - `eventType` string, required — The event type's name

## Response `200`

- MessagePrecheckOut
  - `active` boolean, required — Whether there are any active endpoint that would get sent such a message.

## Other responses

- `400` — Bad request
- `401` — Unauthorized
- `403` — Forbidden
- `404` — Not Found
- `409` — Conflict
- `422` — Validation Error
- `429` — Too Many Requests

---

[API](https://skmtc.dev/svix/apis/svix-api.md) · [All operations](https://skmtc.dev/svix/apis/svix-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/svix/svix-api/revisions/267f7078e536/schema)