Find the right API or MCP server,
without the noise.
apimark is a curated index of public APIs and Model Context Protocol servers, with free tools for everyday developer jobs. Official sources only. No paywalls, no sign-up.
Popular APIs
Well-documented, widely used APIs to build on.
Anthropic Claude API
Claude models for text, code, vision and tool use, with prompt caching and batch processing.
Stripe API
Payments, subscriptions, invoicing and payouts with excellent developer tooling.
Open-Meteo
Open-source weather forecasts and historical data with no key required for non-commercial use.
Resend
Developer-first email API with React Email support.
GitHub REST API
Repositories, issues, pull requests, actions and more.
Frankfurter
Open-source exchange rates API based on European Central Bank reference rates.
MCP servers for AI agents
Connect Claude and other AI clients to real tools, mostly official vendor servers.
GitHub MCP Server
GitHub's official server for repositories, issues, pull requests and Actions.
Playwright MCP
Browser automation via accessibility snapshots, with no vision model required.
Context7
Up-to-date, version-specific library documentation and code examples for coding agents.
Cloudflare MCP Servers
Remote servers for Workers, observability, Radar, browser rendering and more.
Stripe MCP
Interact with the Stripe API and search Stripe documentation.
Notion MCP
Search, read and update Notion pages and databases.
Free developer tools
Fast, private, and they run entirely in your browser.
Cron Expression Explainer
Translate a cron expression into plain English and preview the next run times.
Volumetric Weight Calculator
Work out dimensional (volumetric) weight and the chargeable weight carriers will bill you for.
JSON Formatter & Validator
Pretty-print, minify and validate JSON, with precise error locations. Nothing leaves your browser.
Regex Tester
Test JavaScript regular expressions live, with highlighted matches and capture groups.
Color Contrast Checker
Check text and background colors against WCAG 2.2 AA and AAA contrast requirements.
Unix Timestamp Converter
Convert Unix epoch timestamps (seconds or milliseconds) to dates and back.
Base64 Encoder / Decoder
Encode text to Base64 or decode it back, with full UTF-8 and URL-safe support.
UUID Generator
Generate cryptographically random UUID v4 or time-ordered UUID v7 identifiers in bulk.
Hand-curated
Every listing points to official documentation, and links are re-checked automatically on every update.
Built for decisions
Auth type, free-tier status and category at a glance, with alternatives next to every listing.
Private tools
Our tools process data in your browser. Nothing you paste is uploaded or stored.
Guides
Practical, vendor-neutral explainers.
What Is the Model Context Protocol (MCP)? A Practical Guide
MCP explained without hype: what servers, clients and tools are, local vs remote servers, and how to pick one safely.
7 min readHow to Choose a Third-Party API: A 12-Point Checklist
Before you build on someone else's API, check these twelve things: pricing, limits, reliability, data rights and exit costs.
6 min readCron Syntax Cheat Sheet with 25 Real Examples
A no-nonsense cron reference: the five fields, special characters, macros, 25 copy-paste schedules and common pitfalls.