# 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 2026-09-16).

Sends a message to a specific thread on the402.ai platform using an API key, charged per call via x402 micropayment

## Facts

- Endpoint: POST https://api.the402.ai/v1/threads/thread_9b0adb82375a470b/messages
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-the402-ai-54a047a1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pxcxI8kBxF9M70fGPi4hI

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-54a047a1 -d '<json body>'
```

Example prompt: Send the message 'Your report is ready for review' to thread ID thread_9b0adb82375a470b on the402 platform.

## When to prefer this

Use this endpoint when you need to programmatically post messages to a specific thread on the402.ai platform, especially in automated workflows where micropayment-per-message billing via x402 is acceptable and you have a valid API key.

## Known failure modes

- Invalid or missing thread ID returns an error
- Missing API key or unauthorized access returns 401/403
- Thread not found returns 404
- Insufficient USDC balance or payment failure blocks the request
- Malformed request body with missing required 'id' field returns 400

## How this service works

Send thread message (free with API key)

## Output

A confirmation that the message was posted to the specified thread, likely returning the created message object or a success status along with the message record 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-54a047a1/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)