webtoolz
GitHub

The complete JSON toolkit for developers

webtoolz gives you every JSON operation in one place — format, validate, compare, convert, and repair — without uploading data to a server. Every tool runs 100% in your browser using JavaScript, so your data stays on your device. No sign-up, no rate limits, no tracking.

JSON Studio

Format, minify, validate, and explore JSON with syntax highlighting and tree view

Schema Validator

Validate JSON documents against JSON Schema draft 2020-12 and earlier

JSON to CSV

Export JSON arrays to CSV with configurable delimiters and nested object flattening

JSON to YAML

Convert JSON to YAML for Kubernetes manifests and configuration files

YAML to JSON

Parse YAML files and output formatted JSON for APIs and data processing

JSON Diff

Find structural differences between two JSON documents with highlighted changes

Why webtoolz?

  • Privacy-first — all processing happens client-side, nothing is sent to a server
  • No sign-up or account required — open the page and start working
  • Works offline after the first load — no internet dependency for core tools
  • AI-powered JSON repair fixes broken syntax from copy-paste, trailing commas, and unquoted keys
  • Instant mock APIs — create shareable JSON endpoints for frontend prototyping

Frequently asked questions

Are webtoolz JSON tools free?
Yes, completely free with no usage limits. There are no premium tiers, no rate limiting, and no ads. The tools are open to everyone — developers, students, and teams alike.
Is my data safe?
Your data never leaves your browser. All formatting, validation, diffing, and conversion runs client-side in JavaScript. Nothing is sent to a server, stored, or logged. This makes webtoolz safe for sensitive data, API keys, and internal configuration files.
Do the tools work offline?
Core tools (formatter, validator, diff, converters) work offline after the initial page load. AI-powered features like JSON repair require a network connection since they use a language model, but all other operations are purely client-side.
What JSON standards are supported?
The tools support standard JSON (RFC 8259), JSON5 for lenient parsing, JSON Schema draft 2020-12 / draft-07 / draft-06 / draft-04 for validation, and YAML 1.2 for conversion. CSV output follows RFC 4180.