34 tools live · nothing leaves your machine

Developer tools that never see your data

Paste the API response with the live bearer token in it. Drop the export with real customer emails. It stays on your machine, because there is nowhere for it to go.

JSON tools CSV & spreadsheets tools Dependencies tools LLM & agents tools Time & scheduling tools Hashing & crypto tools JWT & tokens tools How we prove it

Available now

JSON

17 tools

Format, convert, diff and de-secret JSON.

Formatter Minifier JSON → TypeScript JSON → Zod JSON → JSON Schema JSON → Go +11 more

CSV & spreadsheets

4 tools

Convert to JSON, SQL or typed structs, and profile what is in the file.

CSV → JSON CSV → SQL CSV → types CSV analyzer

Dependencies

1 tools

Read a lockfile diff the way a reviewer needs to.

Lockfile diff

LLM & agents

5 tools

Build and debug tool definitions and streamed responses.

Tool definition generator Tool definition linter Streaming response inspector Tool schema budget Tool schema diff

Time & scheduling

2 tools

Epoch conversion and cron, with daylight saving taken seriously.

Timestamp converter Cron tester

Hashing & crypto

2 tools

Digests and signatures, computed where the secret already is.

Hash generator HMAC generator

JWT & tokens

3 tools

Decode tokens, check their claims, and verify signatures locally.

JWT decoder JWT security check JWT signature verifier

Being built

We have not built these yet, so each one points at whoever does it best today — labelled with whether it actually runs on your device. These pages get replaced by our own tools, at the same address.

Regex

curated

Build, test and understand regular expressions.

PDF

curated

Merge, split, compress and edit PDFs.

Images

curated

Compress, convert and strip metadata.

How we prove it

Nothing is uploaded

Each tool is a pure function running in your tab. The pages ship a Content-Security-Policy that forbids network connections outright, so this is enforced by your browser rather than promised by us.

No account, no limits

No sign-up, no file cap, no watermark, no "upgrade to convert more than three files". There is no server to meter.

Works offline

Load a page once, then turn off your network. Everything keeps working — which is the only demonstration of the first point that actually counts.

Every deploy runs an automated check that loads a real page, confirms the tools still work, then tries to exfiltrate data by every means a browser offers — fetch, XHR, WebSocket, beacon, remote module, image pixel. If any of them gets a response, the deploy fails. The check is in the repo.