Fast, private developer tools
Convert CSV, merge PDFs, format JSON — every tool runs in your browser. Nothing is uploaded, and nothing is stored.
Most-used tools
- csvCSV → JSON
Paste or drop a CSV and instantly get structured JSON. Smart numeric coercion, pretty-print, and copy/download.
- jsonJSON → CSV
Convert any JSON array of objects into a clean CSV. Flattens nested keys with dotted notation, escapes commas/quotes per RFC 4180, and offers a customizable delimiter + UTF-8 BOM toggle for Excel compatibility.
- jsonJSON Formatter
Pretty-print messy or minified JSON with adjustable indent (2 / 4 spaces or tabs) and an optional 'sort keys alphabetically' mode. Copy or download the result, all in your browser.
- jsonJSON Validator
Validate JSON against the RFC 8259 spec and see exactly where errors occur — line, column and a human-readable explanation — instead of the generic 'Unexpected token' message you'd get from a native parser.
- jsonJSON Minifier
Remove indentation and whitespace from JSON to produce a single-line compact payload. See the exact byte savings and copy / download the result instantly.
- jsonJSON Tree Viewer
Visualize any JSON document as a virtualized, collapsible tree with type-based color coding, search, expandable paths, and copy-on-click. Stays responsive for very large payloads.
Categories
- CSV Tools21 ready
Fast, private browser-based tools for working with CSV files.
- JSON Tools33 ready
Validate, format, and convert JSON instantly in your browser.
- PDF Tools8 ready
Merge, split, reorder, and convert PDFs without uploading them.
- Image Tools25 ready
Compress, convert, crop, and edit images privately in your browser.
- Text Tools15 ready
Format, transform, and analyze text quickly.
- YAML Tools5 ready
Validate, format, and convert YAML config files in your browser.
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Frequently asked questions
Is DataToolsLab free?
Yes — every tool is free to use, with no signup or account required.
Are my files uploaded to a server?
No. Every tool processes your files locally in your browser. We do not see or store your data.
Do the tools work offline?
Yes. After you visit a tool page once, the service worker keeps it available offline.
Can I bookmark or favorite a tool?
Use the star icon on any tool page to add it to your favorites. Your list is stored locally and never leaves your device.