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11
tools
13
SQL dialects
1,000
UUIDs at once
What it does

What Dev Utilities does.

Small jobs like decoding a token, checking a file hash or tidying a SQL query usually mean searching for a new website each time, and pasting secrets into pages you know nothing about. Dev Utilities gathers eleven of these tools behind one menu, with Ctrl+K to jump between them.

Your input is processed in the tab, JWT tokens, secrets and HMAC keys are never saved, and hashes are computed in plain JavaScript, so the tools also work when opened over a local network address.

JWT decoder with signature check

See the header and claims explained, when the token expires in plain words, and security notes such as an alg of none. HS256, HS384 and HS512 signatures can be checked against a secret.

dev utilities · ctrl+kJWT decoder
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiI0MiIsInJvbGUi….Sfl9…
header { "alg": "HS256", "typ": "JWT" }
sub "42" role "admin" iat 1790503200
exp 1790510400 expires in 2 hours, Sep 27 14:00
✓ signature valid with your secret secret never saved

Base64 and URL encoding

Encode and decode text or files as standard or URL-safe Base64, make data URLs, and see decoded images as images. The URL tool encodes, decodes and splits a URL into its parts and parameters.

Hashes and checksums

Compute MD5, SHA-1, SHA-256, SHA-384, SHA-512 and HMAC of text or files, and paste a checksum to compare it with the result.

UUID generator and inspector

Generate v4 or v7 UUIDs in bulk, or paste any UUID to see its version, variant and, where it has one, its creation time.

Regex tester that explains

Matches are highlighted live, groups and a replace preview are shown, and every token of the pattern is described in plain words. Patterns run with a one second limit, so a runaway pattern cannot freeze the tab.

Code formatters and PDF to text

Beautify or minify HTML, CSS and JavaScript (minified with Terser), format SQL with your keyword case and indentation, and pull the text of every page out of a PDF.

In a minute

See Dev Utilities in action.

A short video of Dev Utilities doing its one job, from an empty screen to the finished result.

Video coming soonDev Utilities in a minute
How it works

How to use Dev Utilities in three steps.

Best for: you want everyday developer utilities in one place that keep tokens, keys and files on your own computer.

01

Find the tool

Pick a tool from the sidebar, or press Ctrl+K and type its name.

02

Paste or drop your input

Paste text, a token or code, or drop a file for Base64, hashing or PDF to text.

03

Copy the result

Adjust the options if needed, then copy or download the result.

Questions

Dev Utilities questions, answered.

How do I decode a JWT?

Split the token at the dots and Base64url-decode the first two parts, which gives you the header and the payload as JSON. The third part is the signature, which you can only check with the key that signed it. Paste the token into the JWT decoder and it shows the claims, the expiry in plain words and, for HS256, HS384 and HS512, whether the signature matches your secret.

Is it safe to paste a JWT or a secret here?

Yes, nothing you paste is sent over the network. The pages have no server behind them and all work happens in your browser tab. JWT tokens, JWT secrets and HMAC keys are not saved at all, not even in your browser. Other inputs and your options are kept in your browser's local storage so they are there when you come back.

Is Base64 encryption?

No. Base64 is an encoding that turns bytes into plain text characters, and anyone can decode it without a key. Use it to move data through text-only channels, never to hide secrets.

What is the difference between UUID v4 and v7?

A v4 UUID is random, while a v7 UUID starts with a timestamp, so v7 ids sort in the order they were created. That makes v7 a good fit for database keys. The UUID tool generates both and shows the creation time hidden in a v7 id.

Which hash should I use to verify a download?

Use SHA-256 when the publisher offers it. MD5 and SHA-1 are still used for checksums but are no longer considered secure against deliberate tampering. Drop the file into the Hash tool and paste the published checksum into the Compare with field to see whether they match.

Can it read scanned PDFs?

Not yet. PDF to text pulls out the text a PDF already contains, page by page. A scanned PDF holds only images of the pages, which would need OCR.

Coming 22 Nov 2026

Dev Utilities is on its way.

It opens on 22 Nov 2026. Everything above is what it will do.

See the release plan
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