Developer Tools
Developers regularly need to inspect a payload, reshape data for another system or test a pattern, and opening a full editor or installing a package for each job is slow. These tools handle the common cases directly in the browser. The HTML editor lets you revise markup beside an isolated live preview. The JSON formatter beautifies, minifies and validates, while four converters move data between JSON and CSV, XML or YAML. The Base64 tool encodes and decodes text and files, including the URL-safe alphabet. The regex tool highlights matches live and supports find and replace with capture groups. Because the work happens locally, you can paste API responses, configuration files and sample data without sending them to a third-party server. Still, avoid pasting live secrets into any web page, and always validate converted output before using it in production.
Tools in this category
9 tools- JSON Formatter & Validator Beautifies, minifies and validates JSON with adjustable indentation and clear error messages. Best for reading API responses and finding syntax mistakes.
- HTML Editor Edit HTML source beside a live preview in your browser. The sandbox blocks scripts and remote resources, making it useful for checking markup without executing embedded code.
- Base64 Encode & Decode Encodes and decodes Base64 for text and files, with URL-safe support. Best for data URIs, tokens and embedding small files; it is encoding, not encryption.
- Password Generator Creates random passwords, Diceware passphrases and PINs with browser cryptography. Best for generating unique credentials without sending them to a server.
- JSON to CSV Converter Converts JSON arrays and objects, including nested data, into CSV. Best for opening API data in a spreadsheet.
- CSV to JSON Converter Parses delimited tables and maps headers to object keys to produce JSON. Best for preparing spreadsheet exports for an API or script.
- JSON to XML Converter Generates XML from JSON data in your browser. Best for feeds, SOAP-style payloads and systems that still expect XML.
- JSON to YAML Converter Turns JSON into readable YAML. Best for configuration files such as Kubernetes manifests or Docker Compose.
- Regex Find & Replace Tool Highlights matches live, supports flags and capture groups such as $1, and has a plain-text mode. Best for testing a pattern before using it in code.
Guides
View all guides- How to Format and Validate JSON Online Learn to format, minify and validate JSON, fix common syntax errors, and convert it to CSV, YAML or XML using browser-based developer tools.
- Markdown Syntax Guide for Beginners Learn Markdown syntax with clear examples of headings, lists, links, code blocks and tables. Use the cheat sheet and preview your writing in a browser.
- JSON vs XML vs YAML: Differences and When to Use Each Compare JSON, XML and YAML with the same data in all three formats, a comparison table, common pitfalls and tips for converting between them.
- What Is Base64 Encoding? How It Works and When to Use It Base64 turns binary data into plain text so it can travel through text-only systems. See how it works step by step, its limits and common mistakes.
Which tool should I use?
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Is your JSON valid and readable?
JSON Formatter & Validator: Format and validate it to find errors and make the structure readable.
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Need a spreadsheet from JSON?
JSON to CSV Converter: Convert arrays of objects to CSV for Excel or Google Sheets.
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Need JSON from a spreadsheet export?
CSV to JSON Converter: Parse the CSV and map each header to a key.
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Need to check HTML markup?
HTML Editor: Edit HTML beside an isolated live preview; scripts and remote resources are blocked.
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Testing a pattern?
Regex Find & Replace Tool: Try the expression against sample text before putting it in code.
More tools you may need
- Text Diff Checker — Text: compare two versions of a config or payload.
- Unit Converter — Converters: convert measurements between units.
- Image Format Converter — Image: convert between JPG, PNG, WebP and AVIF.
Frequently asked questions
Is my data uploaded?
No. The tools process data in your browser. Even so, avoid pasting production secrets into any web page.
Does Base64 protect my data?
No. Base64 is a reversible encoding, not encryption. Anyone can decode it.
How are nested objects handled when converting to CSV?
Nested values are flattened into columns where possible. Check the output when your data has deeply nested or irregular structures.
Which regex flavour does the tester use?
It uses the JavaScript regular expression engine in your browser, so syntax can differ from other languages.