Validate JSON → Compare Versions
- Format and lint data in the JSON Formatter.
- Send the clean payload to Diff Checker to review changes with teammates.
Free tools. Just run.
Free developer utilities – private, instant, browser-based. Build faster with trustworthy formatters, converters, encoders, and viewers that stay in your browser tab.
20+ zero-install utilitiesStructured data & rich metadata for every pagePrivacy-first & no sign-up
All tools+25Formatter+4Viewer+4Datetime+2Converter+3Encoder+3Diff+1Generator+3Image+4Lookup+1Other+0
JSON Formatter
Free online JSON formatter and validator. Beautify, minify, and validate JSON instantly.
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SQL Formatter
Free online SQL formatter. Beautify queries for MySQL, PostgreSQL, SQL Server and more.
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XML Formatter
Free XML formatter and prettifier. Format and validate XML documents instantly.
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CSS Formatter
Free CSS formatter and beautifier. Beautify or minify CSS code with syntax highlighting.
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Base64 Encoder
Free Base64 encoder and decoder. Encode text or decode Base64 strings instantly.
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URL Encoder
Free URL encoder and decoder. Encode special characters for safe use in URLs.
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JWT Decoder
Free JWT decoder and validator. Decode JSON Web Tokens and inspect claims.
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JSON to CSV
Free JSON to CSV converter. Convert JSON arrays to CSV for Excel or Google Sheets.
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cURL Converter
Convert cURL commands to Python, JavaScript, Go, PHP and more. Instant code generation.
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HEIC to JPG
Free HEIC to JPG converter. Convert iPhone photos to JPG – no upload required.
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HEIC to PNG
Free HEIC to PNG converter. Preserve transparency when converting Apple photos.
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HEIC to WEBP
Free HEIC to WEBP converter. Convert to web-optimized format instantly.
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Color Converter
Free color converter. Convert between HEX, RGB, HSL, and CMYK formats.
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Image Converter
Free image converter. Convert between PNG, JPG, WEBP, and GIF with compression.
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UUID Generator
Free UUID generator. Generate random (v4) or timestamp-based (v1) UUIDs instantly.
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Cron Generator
Free Cron expression generator. Create and explain Cron schedules easily.
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QR Code Generator
Free QR code generator. Create custom QR codes with colors and logos.
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Diff Checker
Free text diff checker. Compare two files side-by-side to see differences.
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HTML Viewer
Free HTML viewer with live preview. Write HTML and see results instantly.
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Markdown Viewer
Free Markdown viewer and editor. Write Markdown and see it rendered instantly.
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Mermaid Viewer
Free Mermaid diagram editor. Create flowcharts, sequence diagrams, and more.
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Diagram Viewer
Free diagram viewer and editor. Create visual diagrams with a powerful editor.
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Timestamp Converter
Free Unix timestamp converter. Convert epoch to date and vice versa.
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Current Timestamp
View current timestamp in Unix, ISO 8601, UTC, and local formats. Auto-refreshing.
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What is my IP
Check your public IP address instantly. No tracking, no data storage.
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Popular JSON & API helpers
These are the tools developers pin to their docks. Every card links to a fully indexable page with canonical metadata.
JSON Formatter & Validator
Beautify JSON payloads, validate schemas, and export minified responses.
Open toolCurl → Code Converter
Turn any curl snippet into typed Fetch, Axios, Python, Go, or PHP code.
Open toolDiff Checker
Compare files or snippets side-by-side with syntax-aware highlighting.
Open toolMarkdown Viewer
Write Markdown with GitHub-flavored rendering and export shareable previews.
Open toolConverters & workflows
String together multiple FreeTools.run experiences to turn raw data into production-ready assets in seconds.
Curl Snippet → REST Client
- Paste any CLI command into Curl to Code.
- Copy the generated Fetch or Axios snippet directly into your frontend.
Encode Payload → Share as QR
- Protect secrets via the JWT Decoder or Base64 Encoder.
- Generate a branded QR code for kiosks or quick device handoff.
Frequently asked questions
Straight answers about how we build, deploy, and secure the FreeTools.run ecosystem.
Why build tools under the FreeTools.run domain?
Developers deserve utilities that open instantly, respect privacy, and never ask for an email address. FreeTools.run is our promise that every formatter, converter, and viewer launches as quickly as a terminal command.
How do you keep the tools fast?
Most experiences run entirely in the browser using modern Web APIs and optimized bundles. Heavy components such as the Monaco editor are lazy-loaded, and we pre-render the marketing copy so crawlers and humans see content immediately.
Can I trust the platform with sensitive data?
Yes. Inputs stay on your device by default. Downloads happen locally, and we publish our privacy and uptime commitments directly on each page so you know what to expect.
Privacy & trust, documented
Every tool loads over HTTPS, never stores your payloads, and exposes a canonical URL plus structured data so you can cite, share, and audit the workflow.