Free developer tools
Small, fast utilities that run entirely in your browser. Nothing you paste is uploaded, stored or sent anywhere — the code executes on your own machine, which you can verify by opening the page source or disconnecting from the network.
JSON Formatter and Validator
Format, validate and minify JSON in your browser.
Regex Tester with Live Highlighting
Test regular expressions against sample text and see every match.
Base64 Encoder and Decoder
Convert text to Base64 and back, with full Unicode support.
UUID and Password Generator
Generate UUID v4 identifiers and strong random passwords.
Colour Converter and Contrast Checker
Convert HEX, RGB and HSL and check WCAG contrast.
Software Project Cost Estimator
Estimate a realistic budget and schedule range for a software build.
Why browser-based tools
Most online formatters and converters send your input to a server to do the work. For a configuration file, an API response or a token, that means pasting potentially sensitive data into someone else's logs. Every tool on this page is written in plain JavaScript and performs its work locally, so the data never leaves the tab.
They are also deliberately small. There is no account, no paywall after three uses and no upload step. Open the page, paste, read the answer.
Suggest a tool
If something you use daily is missing, send a suggestion. Tools that are genuinely useful and can run client-side get built.