# 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 a specific conversation thread on the402.ai platform via API key authentication

## Facts

- Endpoint: POST https://api.the402.ai/v1/threads/thread_97db043d70da49a0/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-3322dde4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yIVsc1N2a4RjQRJaZDQxX

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-3322dde4 -d '<json body>'
```

Example prompt: Send the message 'Can you summarize the key findings from the last report?' to thread thread_97db043d70da49a0 on the402.ai.

## When to prefer this

Use this endpoint when you need to programmatically append a message to an existing thread on the402.ai platform, particularly in agentic workflows where conversation state is managed via thread IDs and low-cost per-call pricing ($0.001 USDC) is acceptable.

## Known failure modes

- Invalid or missing API key returns 401 Unauthorized
- Thread ID not found returns 404 Not Found
- Malformed message body returns 400 Bad Request
- Rate limit exceeded returns 429 Too Many Requests
- Payment or billing issue may return 402 Payment Required

## How this service works

Send thread message (free with API key)

## Output

Returns a confirmation of the posted message including the message ID, thread ID, timestamp, and the message content as stored in the thread.

## 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-3322dde4/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)