104 tools · zero uploads

Paste it. Fix it.
Move on.

Formatters, validators, converters and decoders that run entirely in your browser. The tool is the first thing on the page, not the fifth.

No account, no sign-in, no email
Nothing you paste is uploaded
No ads and no third-party trackers
Works with the network switched off

Browse all tools See what is stored

JSON Formatter — liveOpen full tool

{"service":"checkout","version":"2.11.0","replicas":3,"flags":{"retries":true,"timeoutMs":2500},"regions":["eu-west-1","us-east-1"]}

{
  "service": "checkout",
  "version": "2.11.0",
  "replicas": 3,
  "flags": {
    "retries": true,
    "timeoutMs": 2500
  },
  "regions": [
    "eu-west-1",
    "us-east-1"
  ]
}

Valid JSONKeys 7Size 181 B0 requests sent

Edit the left pane. Open your network tab while you do it — nothing is sent.

Most reached for

All 104 tools

A curated shortlist. We have no usage analytics, so this is judgement rather than telemetry.

By category

JSON17

Format, inspect, convert and compare JSON documents.

XML & YAML8

The other two configuration formats you still have to read.

Encode / Decode10

Base64, percent-encoding, entities and hex.

JWT2

Read what a token claims. Decoding is not verification.

Regex3

Test, replace and extract, with a timeout so the tab survives.

Hashing4

Digests, checksums and HMACs via the platform crypto API.

Generators9

Identifiers, passwords and placeholder data from a real CSPRNG.

Text10

Diff, sort, dedupe, recase and count.

Code10

Formatters that parse your code without ever running it.

Data6

CSV and delimited data, parsed properly.

Dates5

Epochs, formats and durations.

URLs6

Parse, build and normalise. Nothing is ever requested.

Colour & CSS5

Conversions and generators for CSS values.

Numbers5

Bases, bit operations, ASCII and byte sizes.

Reference4

Cron, SemVer and lookup tables worth bookmarking.

Why local

Your data never leaves the tab

Most online formatters POST your input to a server to do the work. That is fine for a shopping list and a problem for a production config, a customer export, or a token. DevToolery does the work in JavaScript on your machine, so there is nothing to intercept, log, or retain.

Why it is free

There is nothing to bill for

No servers process your data, so usage costs us close to nothing. There is no premium tier holding a feature hostage and no quota that stops you mid-task. The honest version of the pricing page.

Where the limits are

Stated plainly, on every tool

A browser tab has finite memory, JWT decoding is not verification, and domain parsing without the full Public Suffix List is a guess. Each tool says where it stops being reliable instead of quietly guessing.

Paste it. Fix it.Move on.