Privacy-first utilities

Data tools that never leave your device.

Format, convert and inspect JSON, tokens and text with 23 free tools that run in your browser. Nothing is uploaded.

100% in-browser — how it works
No account
Tokens stay on your device

formatted.json

{
  "app": "LocalFirstTools",
  "version": "2.0",
  "policy": {
    "uploads": "never",
    "storage": "this device",
    "tracking": false
  },
  "tools": [
    "json-formatter",
    "jwt-decoder",
    "regex-tester",
    "text-diff",
    "cron-explainer"
  ],
  "network_requests": 0,
  "works_offline": true
}

Valid JSON·18 lines·Validated locally

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JSON FormatterPretty-print, minify and validate JSON in your browser.JSON MinifierStrip whitespace from JSON and see the bytes saved.JSON ↔ YAMLConvert JSON to YAML and back for configs and manifests.JSON ↔ CSVTurn arrays of objects into CSV rows and back again.JWT DecoderInspect header and payload of a JSON Web Token locally.Base64Convert text to Base64 and back without uploading.URL EncodePercent-encode query strings, paths and fragments.UUID GeneratorCreate version 4 UUIDs with the Web Crypto API.Hash GeneratorSHA-256, SHA-1 and MD5 digests, computed on your device.Case ConvertercamelCase, snake_case, kebab-case, PascalCase and more.TimestampConvert Unix time to ISO dates and back, locally.Regex TesterTest regular expressions with live match highlighting.Text DiffCompare two texts line by line and see what changed.Cron ExplainerTurn cron expressions into plain English and next runs.HTML EntitiesEscape text for HTML and decode entities back to text.Slug GeneratorTurn any title into a clean, URL-safe slug.JSON DiffCompare two JSON documents structurally, ignoring key order.JSON ↔ XMLConvert JSON to XML and back, and pretty-print XML.JSON → TSGenerate TypeScript interfaces from a JSON sample.JSONPathQuery JSON with JSONPath and inspect every match.Query ↔ JSONTurn URL query strings into JSON and back.PasswordsRandom passwords via Web Crypto, on your device.HexConvert text and bytes to hexadecimal and back.

How it works

Paste or drop

Bring JSON, tokens or text into the tool. Nothing leaves this tab.

Runs locally

Formatting and decoding use your browser. There is no processing server.

Copy or download

Take the result back into your editor. We cannot see it.

What the server never sees

The JSON you format, the JWTs and API keys you decode, the passwords you generate and the text you diff. Every tool page is static: there is no upload endpoint, so none of it can appear in a request, a log or a cache — open your browser's network tab and watch.

How we compare

Guides

Frequently asked questions

Is my data uploaded when I use these tools?

No. Every tool runs as JavaScript in your browser tab. There is no upload API and no processing server, so your JSON, tokens and text never appear in a network request — you can verify that in your browser's network tab.

Are the tools free to use?

Yes. All 23 tools are free, with no account, no ads and no usage limits.

Do the tools work offline?

Yes. Once a tool page has loaded, it keeps working even if your connection drops, because all processing happens on your device.

Why is local-first safer for tokens and secrets?

A JWT, API payload or password that never leaves your machine cannot be logged, cached or leaked by a server. With LocalFirstTools there is no server-side processing at all — that is the whole design.

We cannot see your data, because it never reaches us.

That is not a policy footnote. It is how the tools are built.