string.is

The toolkit offers a web‑based interface where developers can paste or type a string and instantly obtain a transformed version using one of roughly fifty built‑in converters and formatters. It automatically detects the input format—such as JSON, CSV, JWT, or plain text—and selects an appropriate conversion path, producing output in the desired target format. The service runs in the browser without setting cookies, enforces a strict Content Security Policy, and relies only on well‑maintained libraries.

It is distributed under the AGPL‑3.0 license, can be self‑hosted, and provides a free tier with no subscription requirement. The codebase is written in TypeScript, with a modular layout that separates identifiers, parsers, outputs, and converters, making it straightforward to add new format pairs. Development, testing, and production builds are automated, and Docker images are available for Linux amd64 and arm64 platforms.

The project targets developers who need quick, privacy‑respecting string manipulations without installing local tools, and it supports modern browsers including Chrome, Safari, Firefox, and Edge.