Free Developer Tools

Ten-second jobs, done in ten seconds

Every developer keeps a mental list of ten-second jobs: decode this token so you can read the claims inside it, pretty-print a response body that arrived as one long line, generate an identifier for a test fixture, encode a value so it survives a query string. None of them are hard. All of them are annoying when the tool you reach for wants an account first.

These pages are the opposite of a platform. Each one is a single static HTML file with the logic inlined. There is no login, no dashboard, no history, no usage tier, and no upsell. Open it, do the thing, close it.

Nothing metered, nothing to join

The usual tax on a small utility is everything wrapped around it: a sign-up wall on the third use, a pretty-print ceiling measured in kilobytes, a decoder that works fine right up until the payload gets interesting.

Nothing here is metered. Every tool arrives complete and free to use as often as you like, with no account, no key and no paid tier planned, which is the version of these utilities that was always worth having.

Each one also installs on its own. Put the JWT decoder on your home screen, or the JSON formatter in your dock, and it opens straight into an empty paste box without the other nine tools coming along for the ride.

The details that save you time

Small utilities fail in small ways that cost real time. Base64 encoders built on the browser'sbtoa throw an exception on any character outside Latin-1, so an accented name or an emoji breaks them, ours encodes to UTF-8 bytes first, so any text round-trips. Decoders frequently accept malformed input and return mojibake instead of an error; ours decodes strictly and tells you when the input is not valid Base64 rather than handing back plausible nonsense.

Where a spec allows more than one behaviour, the tool page says which one it implements and gives you the switch. That is more useful than a tool that silently picks for you and leaves you wondering why two systems disagree.

Linking to these pages

You are welcome to link to any of these tools from documentation, a README, a Stack Overflow answer or an internal wiki. The URLs are stable and will not move. Because there is no account wall, whoever follows the link lands directly on a working tool rather than a signup form, which is usually the point of sharing it.

Made for the way you actually work

Nobody opens a JSON formatter and settles in for the afternoon. You are mid-task, something is wrong, and you need one answer before you can carry on. Every page here opens with the input focused and the result updating as you type, no submit button, no results page, no step between you and the answer.

They also work on a phone, which sounds like a small thing until you are away from your desk and someone sends you a token that will not decode. Big targets, no horizontal scrolling, and no interface that assumes a mouse.

What is coming next

The queue for this category follows what people actually search for rather than what is interesting to build: a JSON formatter and validator, JSON to CSV in both directions, URL encoding, UUID generation in bulk, hash digests, and a JWT decoder that splits the three segments out and pretty-prints the claims.

Each one ships only when it handles the awkward cases properly, malformed input, very large payloads, Unicode outside the ASCII range, because a developer tool that is right ninety percent of the time costs more than it saves. If something you use constantly is missing,say so; requests move things up the queue.