jsonvalidationdebugging
How to Validate JSON: 5 Ways to Check for Errors
Learn 5 ways to validate JSON and catch syntax errors fast. Paste a JSON payload into our free validator and check it in one click.
6 min read
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Free online developer tools that stay in your browser
Pretty print or minify JSON, validate JSON, inspect a JSON payload, run a SQL formatter (SQL beautifier), and base64 decode strings — plus JWT, hashes, regex, PDFs, and QR codes. Fast, free, and 100% client-side.
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Fast, browser-only utilities developers reach for every day.
JSON Formatter & Validator
Pretty print, beautify, minify, and validate JSON online free. Tree view, file upload, private browser-only.
HTML CSS Preview
Write HTML, CSS, and JavaScript and see the result live. Responsive sizes, console output, and download.
Markdown Preview
Open .md files and preview Markdown live, GitHub-style. Edit with a toolbar and convert Markdown to HTML.
PDF Cropper
Crop all PDF pages at once and remove white margins online free. No upload, no watermark.
QR Code Generator
Free QR code generator for links, WhatsApp, WiFi, email, SMS, phone, and vCard. Download PNG or copy Base64.
Base64 Encoder
Encode text, files, and images to Base64 or data URIs. UTF-8 safe, with URL-safe Base64URL option.
JWT Decoder
Decode JSON Web Tokens to read the header, payload, and claims, and check if a token has expired.
Regex Tester
Test JavaScript regular expressions with live match highlighting, capture groups, and replace.
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Jump straight to any JSON, code formatting, encoding, hashing, or PDF utility.
Format, validate, compare, and convert JSON, CSV, and XML — or generate TypeScript, Go, Python, Rust, and SQL.
Beautify, minify, and preview HTML, CSS, JavaScript, Markdown, SQL, XML, and YAML.
Encode and decode Base64, URLs, and JSON Web Tokens.
Generate MD5, SHA-1, SHA-256, SHA-512, and HMAC hashes for text and files.
UUIDs, regular expressions, Unix timestamps, and cron schedules.
Crop, delete, insert, and add pages to PDFs without uploading them.
Create QR codes and barcodes and download them as PNG.
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Format or minify JSON without uploading a JSON payload. Our formatter is 100% client-side and private. Pretty print JSON securely now.
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ReadFrequently asked questions
Everything you need to know about KaviForge browser-based developer tools.
Are KaviForge developer tools completely free and private?
Yes. Every tool on KaviForge runs 100% client-side in your browser using JavaScript and WebAssembly. Your JSON payloads, JWT tokens, code snippets, and PDF files are never uploaded to any server, and no signup or account is required.
Can I minify JSON, validate JSON, and format SQL in the browser?
Yes. The JSON Formatter pretty prints, minify JSON / json minify, and runs JSON validation locally. The SQL formatter is a SQL beautifier for MySQL, PostgreSQL, and T-SQL. The Base64 decoder and Base64 encoder never upload your strings.
What online developer tools are included on KaviForge?
KaviForge includes 45 browser-based tools across 7 categories: JSON & Data Tools (JSON Formatter, JSON Diff, JSON to TypeScript/Go/Python Pydantic/Rust/SQL, CSV to JSON, JSON to CSV, JSON to XML, XML to JSON, YAML to JSON, JSON to YAML), Code Formatters (HTML, CSS, JS, SQL, XML, YAML, Live HTML/CSS Preview, Markdown Preview), Encoders & Decoders (Base64, Image to Base64, Base64 to Image, URL, JWT), Hash Generators (MD5, SHA-256, SHA-512, HMAC), Developer Utilities (UUID v4/v7, Regex Tester, Unix Timestamp, Cron Generator), PDF Tools (PDF Cropper, Delete PDF Pages, Insert Blank PDF Page, Add Image to PDF, PDF Page Manager), and QR/Barcode Generators (WiFi QR, WhatsApp QR, Barcode).
Can I crop or delete PDF pages online without uploading confidential files?
Yes. Both the KaviForge PDF Cropper and PDF Page Manager process documents locally in your browser memory. You can crop margins across all pages at once, delete pages, insert blank pages, or merge PDFs without uploading files or getting watermarks.
Is it safe to paste production JWT tokens or API responses here?
Yes. Because all formatting, validation, and decoding happen locally inside your browser tab with zero network requests for your input data, sensitive API payloads, configuration files, and JWT claims stay on your device.