Guides

Build with APIStack

Practical tutorials with code you can copy. Every example was tested against production, and the responses shown are real.

Connect APIStack to your AI stack

Recipes for agent frameworks and coding assistants. Each one was run against the live MCP server.

Give a Vercel AI SDK app 100+ tools with MCP

Connect the APIStack MCP server to the Vercel AI SDK with createMCPClient and let generateText or streamText search and call 100+ APIs.

Use APIStack tools in the OpenAI Agents SDK (Python and TypeScript)

Connect the APIStack MCP server to an OpenAI Agents SDK agent in Python or TypeScript with MCPServerStreamableHttp: calculators, validators, web and data tools.

Call APIStack from the OpenAI Responses API with a remote MCP tool

Let OpenAI call APIStack for you: add the MCP server as a tool in a Responses API request, with no agent framework and no tool-calling loop in your code.

Load APIStack tools into a LangChain or LangGraph agent

Use langchain-mcp-adapters to load APIStack's MCP tools into a LangChain v1 agent (create_agent) or a LangGraph graph over Streamable HTTP.

Add APIStack to Claude Code, Claude Desktop, Cursor and VS Code

Copy-paste MCP configuration for Claude Code, Claude Desktop, Cursor and VS Code so your coding assistant can call 100+ APIStack tools.

Solve a specific problem

Real requests with the real responses they return, in cURL, JavaScript and Python.

Validate email addresses at sign-up (and catch typos like gmial.com)

Check an email address before you store it: syntax, MX records, disposable domains, role accounts and typo suggestions, with one API call in cURL, JavaScript or Python.

Count business days between two dates, excluding public holidays

Count working days between two dates or add N business days to a date, skipping weekends and US, UK, Canadian, Australian, German, French or Japanese public holidays.

Validate international phone numbers and detect the line type

Validate a phone number in E.164 format, find its country, and tell mobile from landline before you send an SMS, with one GET request.

Check SSL certificate expiry for any domain

Get a domain's TLS certificate details (issuer, validity dates, days until expiry, SANs and chain) with one API call, and alert before it expires.

Calculate loan payments and total interest (without letting an LLM do the math)

Get the monthly payment, total interest and first/last payment split for any loan amount, rate and term with one GET request. Useful for fintech apps and AI assistants.

Convert HTML to clean Markdown for LLM prompts and RAG

Turn HTML into clean Markdown (headings, links, lists and tables preserved) to cut prompt tokens and improve retrieval quality, with one POST request.