# x402engine GPT-5.2 Codex LLM API > x402engine GPT-5.2 Codex LLM API is a paid API for AI agents from x402engine.app, paid per call via x402, $0.06/call, status unknown (last checked 2026-09-15). Runs inference against GPT-5.2 Codex via a pay-per-call HTTP 402 micropayment endpoint on x402engine, billed at $0.06 USDC per call ## Facts - Endpoint: POST https://x402engine.app/api/llm/gpt-5.2-codex - Price: $0.06/call - Payment: x402 - Status: unknown - Last checked: 2026-09-15 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/x402engine-gpt-5-2-codex-llm-api-d122edcd - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_hJWGNgQkgp8r0utZcmBA7 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 x402engine-gpt-5-2-codex-llm-api-d122edcd -d '' ``` Example prompt: Write me a Python function that takes a list of integers and returns the top-K elements using a heap — use the GPT-5.2 Codex model on x402engine and pay per call with USDC. ## When to prefer this Choose this endpoint when you need GPT-5.2 Codex-class code generation capability in an agent pipeline without managing OpenAI API keys or subscriptions, and when your agent already holds USDC on Base, USDm on MegaETH, or USDC on Solana for micropayment billing. Ideal for per-call, pay-as-you-go inference patterns where predictable $0.06 per call cost is acceptable. ## Known failure modes - Insufficient USDC balance causes 402 payment required error with no completion returned - Malformed prompt or missing required fields returns 400 bad request - Model overload or rate limiting may return 429 too many requests - Invalid or expired payment credential returns 401 unauthorized - Long prompts exceeding context window return context length exceeded error ## How this service works 108 production APIs behind HTTP 402 micropayments. 72 LLMs, Kling V3 and Hailuo video generation, image generation, code execution, travel search, web scraping, TTS, and transaction simulation. Pay with USDC on Base, USDm on MegaETH, or USDC on Solana. ## Output Returns a text completion from GPT-5.2 Codex, typically including the generated code or text response, token usage statistics, and model metadata. The response follows standard LLM completion structure. ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402engine-gpt-5-2-codex-llm-api-d122edcd/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from x402engine.app](https://www.zero.xyz/host/x402engine.app/llms.txt)