Best Free APIs for Your OpenClaw Agent

77 curated APIs across weather, productivity, search, AI/ML, and communication — all free tier or open. Make your agent a power tool.

Tags: apis, free, productivity, tools

Category: listicle

Frequently Asked Questions

How do I connect an external API to my OpenClaw agent?

Create a custom skill with a SKILL.md that describes the API and provides curl examples. The agent uses its exec tool to make HTTP requests. For frequently used APIs, you can write a helper script that the skill references.

Do free API tiers have rate limits that affect agent usage?

Yes, most free tiers have rate limits (e.g., 100-1000 requests/day). For personal agent use this is usually plenty. OpenClaw skills should implement backoff logic and respect 429 responses. Check each API's docs for specific limits.

Which free APIs are most useful for a personal assistant agent?

The top picks are: wttr.in or Open-Meteo for weather (no key needed), Gmail API for email, Google Calendar for scheduling, Brave Search for web lookups, and Wikipedia for quick facts. Together they cover 90% of daily assistant tasks.

Can my agent store API keys securely?

Store API keys as environment variables in your shell profile or .env file — never hardcode them in skill files. OpenClaw reads environment variables at startup, so your agent can access them without exposing secrets in config files.