# the402.ai Thread Message Sender

> the402.ai Thread Message Sender is a paid API for AI agents from api.the402.ai, paid per call via x402, $0.001/call, status down (last checked 2026-09-15).

Posts a new message to an existing conversation thread on the the402 platform

## Facts

- Endpoint: POST https://api.the402.ai/v1/threads/thread_70b5802993ec4e0c/messages
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-the402-ai-0637d1c0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3Hr2eRgKRxw9IsE71dx_h

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability api-the402-ai-0637d1c0 -d '<json body>'
```

Example prompt: Post a message to my thread on the402 platform (thread ID: thread_70b5802993ec4e0c) saying 'Please review the latest draft and provide feedback by end of day.'

## When to prefer this

Use this endpoint when you need to programmatically send a message into an existing thread on the the402 platform. Prefer this over alternatives when your workflow involves the402's thread-based messaging system and you already have a thread ID. This is free with an API key (no per-call payment required for authenticated requests).

## Known failure modes

- Invalid or missing API key returns authentication error
- Thread ID does not exist returns 404 not found
- Malformed message body returns 400 bad request
- Insufficient payment (x402) returns 402 payment required
- Rate limiting may return 429 too many requests

## How this service works

Send thread message (free with API key)

## Output

Returns a confirmation that the message was delivered to the specified thread, including the new message object with its ID, timestamp, and content as stored on the the402 platform.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "id"
 ],
 "properties": {
  "id": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-the402-ai-0637d1c0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.the402.ai](https://www.zero.xyz/host/api.the402.ai/llms.txt)