Free online tools for developers

JSON Lab — format, validate and diff JSON

When you paste minified or malformed JSON from an API response, log file, or config, JSON Lab makes it readable in one click. It is built for the everyday tasks developers run into dozens of times a day.

• Format & beautify — indent messy JSON with 2-space formatting and syntax highlighting.
• Minify — compress to a single line for payloads, configs, or storage.
• Validate — catch syntax errors with line and column location, so you fix the right spot.
• Structured tree view — expand, collapse, and search nested objects and arrays; copy any value or JSONPath.
• Two-version diff — see exactly which keys were added, removed, or changed between two JSON documents.

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Epoch Lab — unix timestamp converter with time zones

Timestamps show up everywhere: logs, databases, APIs, cookies. Epoch Lab converts between epoch time and readable dates in both directions, and because servers and teams span the globe, it lets you view the same instant in any time zone.

• Timestamp to date — auto-detects seconds, milliseconds, microseconds and nanoseconds from the digit length.
• Date to timestamp — parse YYYY-MM-DD HH:mm:ss, ISO 8601 with offsets, or plain dates; output in s, ms, µs and ns.
• Any time zone — switch the output between UTC, your local zone, or any IANA zone such as Asia/Tokyo, America/New_York, or Europe/London. Daylight saving time is handled automatically.
• Multiple formats — ISO 8601, RFC 2822, locale string, and relative time ("3 hours ago").
• Live clock — copy the current epoch in seconds or milliseconds with one click.

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HTTP Client — send API requests and import cURL

Whether you are debugging an API, testing an endpoint, or replaying a request copied from browser DevTools, HTTP Client gets you there without installing a desktop app. It works entirely in your browser and supports the workflows developers use every day.

• Import cURL — paste any cURL command (including -H headers, -d body, -b cookies, -u basic auth) and the method, URL, headers and body are filled in automatically.
• All HTTP methods — GET, POST, PUT, DELETE, PATCH, HEAD and OPTIONS, with a method selector and URL bar.
• Custom headers & body — add or remove header key-value pairs; send JSON, x-www-form-urlencoded, or raw text bodies.
• Authentication — Bearer token and Basic auth are built in; the Authorization header is generated for you.
• Tree & formatted response — view JSON responses in a collapsible tree (expand any object or array) or in syntax-highlighted formatted text. Status code, timing, and response headers are all visible.

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QR Code Studio — custom QR codes for links, WiFi and contacts

Share WiFi without typing a password, let people save your contact in one scan, or put a campaign link on a poster. QR Code Studio builds the code in your browser and gives you print-ready files.

• Every content type — links and text, WiFi login (including hidden networks), vCard contacts, email with subject and body, phone numbers and SMS.
• Brand it yours — foreground and background colors, transparent background, optional center logo with automatic high error correction.
• PNG & SVG export — raster files for screens and crisp vector files for print, from 256 to 2048 pixels, with adjustable quiet zone.

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Why use WeUtil

• Privacy first — all processing happens in your browser. Your JSON, dates, and timestamps are never uploaded anywhere.
• Instant — no page reloads, no server round-trips. Conversions and formatting happen as you type.
• Consistent — every tool shares the same design, keyboard shortcuts, and dark/light theme.
• Free — all tools are free to use, with no account required.