101Tool

Free browser-based API Studio, PDF optimizer, and developer toolkit

101Tool is a lightweight, free utility platform for developers and small teams. Use its REST, GraphQL and WebSocket API Studio with multi-request tabs, environments, tests, response variable extraction, collection runners, Postman Collection imports and OpenAPI imports. Optimize PDFs locally in the browser, convert JSON into TypeScript, Go or Python Pydantic models, and use practical encoding, color, ASCII, Base64, URL, hexadecimal and text tools. Korean and English interfaces are available without signup or installation.