# SingIt Ask

> LLM chat completions API, OpenAI-compatible: one endpoint for 100+ models (Claude, GPT, Gemini, Grok, DeepSeek, Qwen), no API key or account, pay per call in USDC. Call it when an agent needs an LLM answer, a second opinion, or a model it has no key for. SingIt Ask; models at GET /v1/models.

## What it is

An x402 seller: language-model chat completions, Anthropic's Messages and OpenAI's Responses formats, images, speech and Exa web search, page contents and cited answers, each paid per call. No accounts or API keys.

## How to pay

x402 v2. Call a paid route below with no payment and read the 402 response's PAYMENT-REQUIRED header for its offers: `upto`, listed first (metered to actual cost, up to the ceiling it names), or `exact` (a flat price for a typical-length answer, about 30% of max_tokens), in USDC on Base or Solana. Sign one and retry with the signature in the PAYMENT-SIGNATURE header. Live prices and models: https://ask.singitai.app/openapi.json and https://ask.singitai.app/v1/models. For Claude Opus, sign `upto`: its `exact` price carries room for thinking tokens and is usually dearer than the answer used (recommendedScheme in https://ask.singitai.app/pricing.json). Step by step: https://github.com/bubon-ik/SingItAI/blob/main/docs/first-paid-call.md

## Free to try

Model "free/openai-gpt-oss-20b", "free/gemma-4-e2b", "free/gemma-3-27b-it", "free/mistral-small-3.2-24b-instruct", "free/qwen3-coder-30b-a3b-instruct", "free/deepseek-v4.1-flash" on POST https://ask.singitai.app/v1/chat/completions answers with no payment: 20 answers a day per network (IPv4 /24, IPv6 /64), up to 400 tokens and 4000 characters each, resetting at midnight UTC. Shared daily cost cap: $0.25; free answers may run out for the day (free_budget_exhausted). When they are used up, drop the free/ prefix to pay per answer, or come back tomorrow.

## Paid routes

- POST https://ask.singitai.app/v1/chat/completions
- POST https://ask.singitai.app/v1/messages
- POST https://ask.singitai.app/v1/responses
- POST https://ask.singitai.app/v1/images/generations
- POST https://ask.singitai.app/v1/audio/speech
- POST https://ask.singitai.app/v1/chat/claude-opus-5.5
- POST https://ask.singitai.app/v1/chat/claude-sonnet-5.5
- POST https://ask.singitai.app/v1/chat/claude-haiku-5.5
- POST https://ask.singitai.app/v1/chat/gpt-5.6-sol
- POST https://ask.singitai.app/v1/chat/gpt-5.6-terra
- POST https://ask.singitai.app/v1/chat/gpt-5.5
- POST https://ask.singitai.app/v1/chat/gemini-3.1-pro-preview
- POST https://ask.singitai.app/v1/chat/gemini-3.8-flash
- POST https://ask.singitai.app/v1/chat/grok-4.7
- POST https://ask.singitai.app/v1/chat/kimi-k3
- POST https://ask.singitai.app/v1/chat/deepseek-v4-pro
- POST https://ask.singitai.app/v1/chat/deepseek-v4.1-flash
- POST https://ask.singitai.app/v1/chat/qwen3.8-max-0902
- POST https://ask.singitai.app/v1/chat/glm-5.3
- POST https://ask.singitai.app/v1/exa/search
- POST https://ask.singitai.app/v1/exa/contents
- POST https://ask.singitai.app/v1/exa/answer

## Free

- GET https://ask.singitai.app/v1/models — models and their prices
- GET https://ask.singitai.app/v1/images/models — image models and their prices
- GET https://ask.singitai.app/v1/audio/models — voice models and their prices
- GET https://ask.singitai.app/v1/prices — crypto, metal and fx prices, no payment
- GET https://ask.singitai.app/health — service, model and payment-rail status
- GET https://ask.singitai.app/numbers.json — measured usage numbers with definitions

## Links

- OpenAPI: https://ask.singitai.app/openapi.json
- x402 discovery: https://ask.singitai.app/.well-known/x402
- llms.txt: https://ask.singitai.app/llms.txt
- Models: https://ask.singitai.app/v1/models
- Docs: https://singitai.app/developers/
- First paid x402 call: https://github.com/bubon-ik/SingItAI/blob/main/docs/first-paid-call.md
- MCP server (API key, not x402): https://app.singitai.app/mcp, see https://singitai.app/llms.txt