# x402engine — Pay-per-call APIs for AI Agents > x402engine — Pay-per-call APIs for AI Agents is a paid API for AI agents from x402engine.app, paid per call via x402, $0.04/call, status unknown (last checked 2026-09-15). ## Facts - Endpoint: POST https://x402engine.app/api/llm/gpt-5.6-terra - Price: $0.04/call - Payment: x402 - Status: unknown - Last checked: 2026-09-15 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/api-llm-gpt-5-6-terra-b0570187 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_769zHP-Rk_IU_Ph6ub7FU 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-llm-gpt-5-6-terra-b0570187 -d '' ``` ## 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. ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-llm-gpt-5-6-terra-b0570187/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)