---
title: "Reject Block Trade Proposal"
method: POST
path: "/communications/block-trade-proposals/{block_trade_proposal_id}/reject"
tags: ["communications"]
---

# Reject Block Trade Proposal

`POST /communications/block-trade-proposals/{block_trade_proposal_id}/reject`

## Request

- Base URL: `https://external-api.kalshi.com/trade-api/v2`
- URL: `https://external-api.kalshi.com/trade-api/v2/communications/block-trade-proposals/{block_trade_proposal_id}/reject`
- Auth: API key in header `KALSHI-ACCESS-KEY` and API key in header `KALSHI-ACCESS-SIGNATURE` and API key in header `KALSHI-ACCESS-TIMESTAMP`

Endpoint for rejecting a pending block trade proposal. Either counterparty can reject it, but not the proposer, which cancels it instead.

## Path parameters

- `block_trade_proposal_id` string, required

## Response `204`

Block trade proposal rejected successfully

## Other responses

- `400`: Bad request - invalid input
- `401`: Unauthorized - authentication required
- `404`: Resource not found
- `409`: Conflict - resource already exists or cannot be modified
- `500`: Internal server error

## Changes

> 80 revisions in range; 1 not diffed.

- **2026-11-05** `74af7082044c`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/kalshi/apis/kalshi-trade-api-manual-endpoints/changes/communications/block-trade-proposals/:block_trade_proposal_id/reject/post.md)

---

[API](https://skmtc.dev/kalshi/apis/kalshi-trade-api-manual-endpoints.md) - [All operations](https://skmtc.dev/kalshi/apis/kalshi-trade-api-manual-endpoints/llms.txt) - [OpenAPI document](https://skmtc.dev/kalshi/apis/kalshi-trade-api-manual-endpoints/revisions/e7b7708289fa?raw)