---
title: "Validate a proposed Stacks block"
method: POST
path: "/v3/block_proposal"
tags: ["Mining"]
---

# Validate a proposed Stacks block

`POST /v3/block_proposal`

Used by stackers to validate a proposed Stacks block from a miner.

**This API endpoint requires a basic Authorization header.**

## Response `202`

Block proposal has been accepted for processing. The result will be returned via the event observer.

## Other responses

- `400` — Endpoint not enabled.
- `401` — Unauthorized.
- `429` — There is an ongoing proposal validation being processed, the new request cannot be accepted until the prior request has been processed.

## Changes

- **2025-06-26** `2fc5956efe3d` — 3 breaking, 4 info
  - removed the media type `application/json` for the response with the status `400`
  - removed the media type `text/plain` for the response with the status `400`
  - removed the media type `text/plain` for the response with the status `401`
  - api operation id `postBlockProposal` removed and replaced with `post_block_proposal`
  - …3 more
- **2025-06-25** `87a7fe30e436` — 2 info
  - the `block` request property's minLength was decreased from `400` to `0`
  - removed the pattern `^([0-9a-fA-F]{2})+$` from the request property `block`

[Change history](https://skmtc.dev/stacks-network/apis/stacks-3-0-rpc-api/changes/v3/block_proposal/post.md)

---

[API](https://skmtc.dev/stacks-network/apis/stacks-3-0-rpc-api.md) · [All operations](https://skmtc.dev/stacks-network/apis/stacks-3-0-rpc-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/stacks-network/stacks-3-0-rpc-api/revisions/7e7074ff0803/schema)