no signup · all in one place · free
Free online tools — formatters, webhook testing, and more.
a2zutil.dev is a fast, growing library of free online tools — formatters, converters, encoders and live testing utilities — starting with JSON, SQL, string/ID tools and a Webhook, with new additions shipping regularly.
The toolkit
Pick a tool and get straight to work.
JSON Formatter
Pretty-print, minify and validate JSON, with auto-repair for common invalid JSON.
OpenJSON to CSV
Convert a JSON array of objects to CSV, or paste CSV back to JSON.
OpenJSON Compare
Diff two JSON documents and see every added, removed and changed value.
OpenSQL Formatter
Indent messy queries with uppercase or lowercase keywords.
OpenCase Converter
camelCase, snake_case, kebab-case, PascalCase and more, all at once.
OpenBase64 Encoder / Decoder
Encode or decode Base64, including the URL-safe alphabet.
OpenURL Encoder / Decoder
Percent-encode or decode a URL component.
OpenUUID v4 Generator
Generate one or many cryptographically random UUID v4s.
OpenText Transform
Turn a list of lines into a delimited string, and back.
OpenJWT Decoder
Coming soon.
Dev Form Builder
Coming soon.
WebSocket Tester
Coming soon.
Why a2zutil.dev
No sign-in required
Open a tool and use it. No account, no email, no paywall prompt.
Free to use
Every tool here is free to use — no paywall, no credit card, no trial that expires.
Instant and private
Most tools run locally in your browser — that data never leaves the page. The Webhook, temporary email and BIN checker are the exceptions, since each needs a network round trip to do its job.
Works on any device
Responsive layouts for quick checks on phone, tablet or desktop.
Live testing tools
Get a temporary webhook URL or email address and watch real deliveries arrive live, no signup required.
Latest from us and around the internet
See all5 Habits for Debugging Messy JSON Payloads Faster
The difference between a two-minute payload review and a twenty-minute one usually comes down to a few small habits.
SQL Formatting Conventions That Make Code Review Easier
A query that's easy to review is one where the diff shows the actual change, not a reflow of every line around it.
Testing Webhooks Locally Without Exposing Your Machine
You don't need to punch a hole in your firewall to see what a provider actually sends before your endpoint touches it.
A growing library of free online tools
Most of these utilities live on scattered single-purpose sites, or in desktop apps that want an account before they will pretty-print a payload. a2zutil.dev takes the opposite approach: one fast, clean interface for the utilities people reach for constantly — JSON formatting, SQL formatting, string and ID conversion, webhook testing, and steadily more beyond that. The catalog is built to keep expanding, from everyday text and encoding utilities to API and data-format tools, without ever asking for a signup or slowing the page down.
Every formatter runs as pure client-side JavaScript. When you paste a JSON response from a staging API, a query pulled from a slow-query log, or a string you need re-cased or encoded, that text is processed entirely in your own browser and never uploaded. That matters whenever the payload you are debugging contains customer data, internal identifiers, or anything else you would not paste into a random website.
The Webhook is the one networked tool in the toolkit: it hands you a temporary URL you can drop straight into any provider's webhook configuration — Stripe, GitHub, Shopify, your own service — and shows each delivery live, headers and body included. It is built for test events during integration and debugging work, and sessions expire automatically so nothing lingers.
Everything on a2zutil.dev is free, anonymous, and built to outlast today's tool list. New formatters, converters and testing utilities get added regularly, so bookmark the tool you use most — or start from the homepage, which stays the fastest way to find whatever gets added next.
Have questions?
Pricing, accounts, data privacy and which tools are available — answered on one page.