# OpenAI-Compatible Chat Completions (Fast Tier, x402)

> OpenAI-Compatible Chat Completions (Fast Tier, x402) is a paid API for AI agents from d1zz2d7coymbr5.cloudfront.net, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Provides OpenAI-compatible chat completions with streaming support, accessible via x402 micropayment at $0.002 USDC per call.

## Facts

- Endpoint: POST https://d1zz2d7coymbr5.cloudfront.net/v1/chat/completions
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/openai-compatible-chat-completions-fast-tier-x402-dda69797
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5SSRgL1qGXC8VjafUetHF

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 openai-compatible-chat-completions-fast-tier-x402-dda69797 -d '<json body>'
```

Example prompt: Ask the LLM: given system prompt 'You are a helpful assistant', and user message 'Explain the difference between supervised and unsupervised learning in two sentences', get a streaming chat completion response.

## When to prefer this

Choose this endpoint when you need a pay-per-call OpenAI-compatible LLM with no subscription or API key management, especially useful for agents that need to make occasional or bursty LLM calls and want to pay micro-amounts via x402 USDC. Prefer this over managed OpenAI accounts when operating in autonomous agent pipelines that handle their own payments, or when building cost-accountable multi-agent systems where each LLM call should have a discrete, traceable cost.

## Known failure modes

- Payment not included or insufficient USDC — 402 Payment Required response
- Invalid or missing messages array — 400 Bad Request
- Unsupported model identifier — 400 or 404 error
- Rate limit exceeded — 429 Too Many Requests
- Upstream LLM provider outage — 502 or 503 error
- Malformed request body — 400 with JSON parse error
- Stream connection dropped mid-response — incomplete SSE stream

## How this service works

OpenAI-compatible chat completion (fast tier). Streaming supported.

## Output

Returns an OpenAI chat.completion object containing the assistant's generated message, finish reason, token usage statistics, and model metadata. When stream=true, returns server-sent events (SSE) with incremental delta chunks of the assistant message followed by a [DONE] signal.

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "description": "OpenAI chat.completion (or SSE stream when stream=true)"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/openai-compatible-chat-completions-fast-tier-x402-dda69797/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from d1zz2d7coymbr5.cloudfront.net](https://www.zero.xyz/host/d1zz2d7coymbr5.cloudfront.net/llms.txt)