# 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 2026-10-23).

Sends a message to a specific thread on the the402.ai platform using a thread ID

## Facts

- Endpoint: POST https://api.the402.ai/v1/threads/thread_8a312604bafb4876/messages?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-the402-ai-fb109894
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zQ1N9syHBm3eajNdxbc5O

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-fb109894 -d '<json body>'
```

Example prompt: Send a message to thread ID thread_8a312604bafb4876 on the402.ai saying 'Please provide the status update for project Alpha.'

## When to prefer this

Use this endpoint when you need to programmatically send a message to a specific existing thread on the the402.ai platform, especially in agentic workflows where threads are used to coordinate tasks or conversations. Best suited when you already have a thread ID and want to append a message to it at low cost ($0.001 USDC).

## Known failure modes

- Invalid or missing thread ID returns an error
- Unauthorized access if API key is invalid or missing
- Thread does not exist or has been deleted
- Payment failure if USDC balance is insufficient for the $0.001 per call fee
- Malformed request body missing the required 'id' field

## How this service works

Send thread message (free with API key)

## Output

A confirmation that the message was successfully posted to the specified thread, potentially including the message ID or updated thread state.

## 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-fb109894/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)