Is the data I paste in sent anywhere?

For the formatters, encoders and generators, no: they run entirely in your browser. The DNS and record lookups do send the domain name to public resolvers, because that is how a lookup works, but your pasted JSON, tokens and text never leave the page.

Is it safe to paste a JWT here?

The decoding happens locally, so the token is not transmitted. Still, treat any production secret with care and rotate it if you are unsure. For a token you are actively debugging, local decoding is the safe way to read it.

Do I need to install anything?

No. These replace the small CLI utilities and random sites you would otherwise reach for, with nothing to install and no account.

Yes, all of them, paid for by light advertising rather than a subscription.

Developer and network tools

Format, decode, generate and look things up, from JSON and JWTs to DNS and SPF records.

Open the tools 137 tools, all in your browser

This is the drawer of small utilities you reach for mid-task: pretty-print a blob of JSON, decode a JWT to see what is actually in it, generate a UUID, or check what a regex matches. None of them need a login, and the data you paste in stays in the page.

It also covers the network side. You can run a live DNS, MX or reverse lookup, work out a subnet, or check whether a domain SPF, DKIM and DMARC records are set up the way you meant. The lookups query public DNS from your browser; the formatters and generators do everything locally.

Which tool for which job

JSON formatter: Turn a minified or broken blob into something readable, and see exactly where it fails to parse.
JWT decoder: Read the header and payload of a token to debug an auth problem, without sending it anywhere.
Base64 encode and decode: Move between raw text and Base64 for a data URI, a config value, or a quick sanity check.
Regex tester: Try a pattern against real sample text and see the matches highlighted as you type.
DNS and MX lookup: Check what a domain actually resolves to right now when mail or a site is misbehaving.
SPF, DKIM and DMARC checker: Confirm your email records are valid before a campaign lands in spam.

Every developer and network tool

Open tools

Questions about the developer tools

Is the data I paste in sent anywhere?: For the formatters, encoders and generators, no: they run entirely in your browser. The DNS and record lookups do send the domain name to public resolvers, because that is how a lookup works, but your pasted JSON, tokens and text never leave the page.
Is it safe to paste a JWT here?: The decoding happens locally, so the token is not transmitted. Still, treat any production secret with care and rotate it if you are unsure. For a token you are actively debugging, local decoding is the safe way to read it.
Do I need to install anything?: No. These replace the small CLI utilities and random sites you would otherwise reach for, with nothing to install and no account.
Are these free?: Yes, all of them, paid for by light advertising rather than a subscription.

Developer and network tools live on /dev

Free, no account, nothing uploaded.

Open the tools