Free Developer Tools Online
The utilities you reach for daily, running locally so payloads stay private.
This is a set of free developer tools online for the lookups and conversions that interrupt real work: a JSON formatter to pretty-print and validate payloads, Base64 encode/decode for tokens and data URIs, URL encode/decode for query strings, and a hash generator covering MD5, SHA-1, SHA-256 and SHA-512. A Unix timestamp converter translates epoch values in logs, and a binary translator covers the low-level fun. For front-end work there are HEX to RGB and RGB to HEX converters, a color picker and a CSS gradient generator with copy-ready code.
The design decision that matters: every tool runs 100% in your browser. Nothing you paste is transmitted, which means API responses full of customer data, JWTs, credentials and internal config can be formatted, decoded and hashed without leaving your machine. That is the difference between these and the average paste-your-token-into-a-random-server tool site.
Frequently asked questions
Are these developer tools free?
Yes, free, unlimited and account-free. They are simple utilities and stay that way; no premium tier is waiting behind the fifth use.
Is it safe to paste tokens and API responses here?
Yes. All processing is client-side JavaScript. Your input never reaches a server, is never logged, and disappears when you close the tab. That is precisely why these tools run locally.
Do they work offline?
Once a tool page has loaded, the processing itself needs no network connection, since your browser does all the work.
Do they work on mobile?
Yes, everything works in phone browsers. Decoding a timestamp or Base64 string from your phone mid-incident is a legitimate use case, and it works.
Which hash should I use for checksums?
SHA-256 is the sensible default; it is what most projects publish today. MD5 and SHA-1 are fine only for non-security jobs like deduplication, since both are cryptographically broken.