The API for tool use
Access the open ecosystem of MCP tools with one line of code using our completions API that supports every LLM.
1curl -X POST https://api.opentools.com/v1/chat/completions
2-H "Authorization: Bearer <OPENTOOLS_API_KEY>"
3{
4 "model": "google/gemini-2.0-flash-lite-001",
5 "messages": [
6 {
7 "role": "user",
8 "content": "Help me book a 5-star hotel in the next 2 hours"
9 }
10 ],
11 "tools": [
12 { "type": "mcp", "ref": "google-maps" }
13 ]
14}One API, every tool
Browse our registry of MCP servers to augment your LLM with capabilities like web search, real-time location data, and web scraping. No personal API keys needed.
Switch LLMs seamlessly
Use any LLM you want — your application stays resilient against outages. Our API is OpenAI-compatible and backwards compatible with traditional function calling.
Transparent pricing
You only pay for tool execution because we charge tokens at-cost, all in one unified billing portal. No more juggling multiple LLM and external service accounts.
Frequently asked questions