Free online utility tools for people, programs and AI agents
PithLab is a collection of small tools that each do one job: format JSON, decode a JWT, check a domain's email security, work out a loan or test a regex. The same tools are available over a JSON API and an MCP server.
The PithLab home page with tool search, the paste-anything box, popular tools, categories and links to the ImageSpark and PDFSpark sister sites.
Where they were stuck.
Quick jobs like formatting JSON or checking a DNS record usually mean a search, an ad-heavy page and pasting data into someone else's server. PithLab needed to be the fast, trustworthy place for those jobs, for people in a browser and for programs and AI agents.
How we shipped it.
- 01
Ran 180 of the 192 tools entirely in the browser, so what people paste never leaves their device. The few server-backed checks, like DNS, WHOIS and SSL, say so on the page.
- 02
Made every tool free without an account. Accounts add API keys, saved recipes and higher Pro limits.
- 03
Exposed 184 tools through a REST API and a Model Context Protocol server, so Claude, Cursor and other agents can call them as tools.
- 04
Built static, prerendered pages with a paste-anything box that suggests the right tool, and left image and PDF work to the ImageSpark and PDFSpark sister sites.