Featured
JSON Formatter
JSON
Format, minify, and validate JSON with optional key sorting.
Free online utilities
Developer Tools
Essential online developer tools to format, validate, encode, decode, test, and optimize your code. Fast, reliable, and easy to use.
- Easy to use
- Fast to start
- Clear processing
- No registration
Quick answer
What developer tools does Utilnivo provide?
Utilnivo developer tools format and validate JSON, XML, YAML, and SQL; encode URLs and Base64; decode JWTs; test regex; and generate UUIDs—all locally in the browser without uploading your code to Utilnivo servers.
Spotlight
New & Featured Developer Tools
Common tasks
· multi-step in your browser70 tools
- Featured
JSON Formatter
JSON
Format, minify, and validate JSON with optional key sorting.
- NewFeatured
API Response Formatter
Formatters
Pretty-print JSON or XML API responses with auto-detection.
- NewFeatured
API Tester
Tools
Send HTTP requests from your browser and inspect responses.
- Featured
Base64 Encoder & Decoder
Encoding
Encode and decode text with Base64.
- NewFeatured
Border Radius Generator
Tools
Control each corner radius and copy CSS border-radius.
- NewFeatured
Box Shadow Generator
Tools
Design CSS box shadows with live preview and copy-ready code.
- NewFeatured
Clamp Typography Generator
Tools
Generate fluid CSS font-size with clamp().
- Featured
Color Contrast Checker
Tools
Check WCAG contrast ratios between two colors.
- Featured
Color Converter
Tools
Convert colors between HEX, RGB, HSL, and HSV.
- Featured
Cron Expression Explainer
Security
Explain 5-field cron expressions in plain language.
- Featured
Cron Generator
Security
Build 5-field cron expressions from presets.
- Featured
CSS Formatter and Minifier
Formatters
Pretty-print or minify CSS in one panel—switch Format and Minify anytime.
- NewFeatured
CSS Grid Generator
Tools
Build CSS Grid templates with columns, rows, and gap.
- Featured
CSS Minifier
Formatters
Compress CSS by removing comments and whitespace—see bytes saved.
- Featured
CSV to JSON Converter
JSON
Convert CSV with headers into a JSON array of objects.
- Featured
CSV Viewer and Formatter
XML & YAML
Preview CSV as a table and reformat it cleanly.
- Featured
cURL Builder
Network
Build curl commands from method, URL, headers, and body.
- Featured
cURL Formatter
Formatters
Parse and format curl commands for readability.
- Featured
DNS Lookup
Network
Look up DNS records for a domain.
- NewFeatured
Environment Variable Formatter
Formatters
Normalize messy env files into clean KEY=value .env format.
- Featured
File Checksum Calculator
Encoding
Generate SHA-256 file checksums on your device.
- NewFeatured
Flexbox Visualizer
Tools
Explore CSS flexbox alignment with a live item preview.
- NewFeatured
Gradient Generator
Tools
Create CSS linear gradients with angle and color controls.
- Featured
Hash Generator
Encoding
Generate SHA-256, SHA-384, and SHA-512 hashes.
- NewFeatured
HTML CSS JS Playground
Tools
Try HTML, CSS, and JavaScript snippets in a sandboxed preview.
- Featured
HTML Encoder and Decoder
Tools
Encode or decode HTML entities.
- Featured
HTML Formatter and Minifier
Formatters
Format or minify HTML markup on your device.
- Featured
HTML Minifier
Formatters
Minify HTML with a dedicated compression page.
- Featured
JavaScript Formatter and Minifier
Formatters
Pretty-print or minify JavaScript in one panel—switch modes on the same input.
- Featured
JS Beautifier
Formatters
Beautify JavaScript with readable indentation—formatting only, no minify.
- Featured
JS Minifier
Formatters
Compress JavaScript—strip comments and whitespace with byte savings shown.
- Featured
JSON Compare
JSON
Compare two JSON documents and list structural differences.
- NewFeatured
JSON Schema Generator
JSON
Generate JSON Schema from sample JSON automatically.
- Featured
JSON to CSV Converter
JSON
Convert a JSON array of objects into CSV.
- Featured
JSON Validator
JSON
Validate JSON syntax and show parse errors.
- Featured
JWT Decoder
JWT
Decode JWT header, payload, and expiry—including Bearer tokens—on your device.
- Featured
JWT Encoder
JWT
Encode and sign JWTs with HS256 on your device.
- NewFeatured
JWT Expiry Checker
JWT
Check if a JWT is expired and when it expires in your timezone.
- Featured
JWT Generator
JWT
Generate sample JWTs with common claims.
- Featured
Markdown Previewer
Tools
Preview GitHub-flavored Markdown as HTML.
- NewFeatured
Regex Cheat Sheet Generator
Tools
Build a printable regex cheat sheet for patterns you need.
- Featured
Regex Tester
Tools
Test regular expressions against sample text.
- Featured
Short Link Generator
Tools
Create compact short links for long URLs.
- Featured
SQL Formatter
Formatters
Format SQL queries for readability.
- Featured
SSL Checker
Network
Check certificate transparency records for a domain.
- Featured
Timestamp Converter
Tools
Convert between Unix timestamps and human-readable dates.
- Featured
URL Encoder/Decoder
Encoding
Encode or decode URL-safe text.
- Featured
UUID Generator
Identifiers
Generate UUIDs for apps, tests, and databases.
- Featured
WHOIS Lookup
Network
Look up domain registration details via RDAP.
- Featured
XML Compare
XML & YAML
Compare two XML documents and list structural differences.
- Featured
XML Formatter
XML & YAML
Format, minify, and validate XML with readable indentation.
- Featured
XML Validator
XML & YAML
Validate XML structure and report errors.
- Featured
YAML Formatter and Validator
XML & YAML
Format and validate YAML documents.
- Featured
YAML Validator
XML & YAML
Validate YAML documents and report errors.
Code Diff
Tools
Compare two text files side by side with line diffs.
Cubic Bezier Generator
Tools
Design CSS cubic-bezier easing curves with live preview.
Encoding Converter
Tools
Convert text to and from hex, binary, ASCII, and Unicode.
Escape and Unescape
Tools
Escape or unescape JavaScript, JSON, HTML, and URL text.
HMAC Generator
Tools
Generate HMAC-SHA256, SHA384, and SHA512 digests locally.
JSON Minifier
JSON
Minify JSON into a compact single line on your device.
JSON Path Explorer
JSON
Query JSON with simple paths and browse a document tree.
JSON to YAML
JSON
Convert JSON documents into YAML.
JWT Verifier
JWT
Verify JWT signatures locally with WebCrypto—HS*, RS*, and ES256.
Mock Data Generator
Tools
Generate fake JSON records from a simple schema.
Query String Parser
Tools
Parse URL and query strings into JSON and a params table.
Regex Debugger
Tools
Debug regex patterns with matches and token explanations.
ULID Generator
Tools
Generate sortable ULIDs locally for apps and tests.
User-Agent Parser
Tools
Parse user-agent strings into browser, OS, and device fields.
XML to JSON
JSON
Convert XML documents into JSON safely.
YAML to JSON
JSON
Convert YAML documents into JSON.
Complete Developer tool index (70)
- JSON Formatter
- API Response Formatter
- API Tester
- Base64 Encoder & Decoder
- Border Radius Generator
- Box Shadow Generator
- Clamp Typography Generator
- Color Contrast Checker
- Color Converter
- Cron Expression Explainer
- Cron Generator
- CSS Formatter and Minifier
- CSS Grid Generator
- CSS Minifier
- CSV to JSON Converter
- CSV Viewer and Formatter
- cURL Builder
- cURL Formatter
- DNS Lookup
- Environment Variable Formatter
- File Checksum Calculator
- Flexbox Visualizer
- Gradient Generator
- Hash Generator
- HTML CSS JS Playground
- HTML Encoder and Decoder
- HTML Formatter and Minifier
- HTML Minifier
- JavaScript Formatter and Minifier
- JS Beautifier
- JS Minifier
- JSON Compare
- JSON Schema Generator
- JSON to CSV Converter
- JSON Validator
- JWT Decoder
- JWT Encoder
- JWT Expiry Checker
- JWT Generator
- Markdown Previewer
- Regex Cheat Sheet Generator
- Regex Tester
- Short Link Generator
- SQL Formatter
- SSL Checker
- Timestamp Converter
- URL Encoder/Decoder
- UUID Generator
- WHOIS Lookup
- XML Compare
- XML Formatter
- XML Validator
- YAML Formatter and Validator
- YAML Validator
- Code Diff
- Cubic Bezier Generator
- Encoding Converter
- Escape and Unescape
- HMAC Generator
- JSON Minifier
- JSON Path Explorer
- JSON to YAML
- JWT Verifier
- Mock Data Generator
- Query String Parser
- Regex Debugger
- ULID Generator
- User-Agent Parser
- XML to JSON
- YAML to JSON
- Free Developer Tools
- No Account Required
- Runs in Your Browser
- Privacy Conscious
- Clear Processing
Category guide
About developer tools
Developer tools focus on formatting, encoding, and inspection tasks you often need while building or debugging. Format JSON, XML, SQL, HTML, CSS, JavaScript, or YAML; encode Base64 or URLs; decode JWTs; generate UUIDs; compare documents; or test regular expressions against sample text.
Each utility is meant to be fast and self-contained. Paste a snippet, transform it, and copy the result. These formatters and encoders work instantly without extra setup. Invalid input should surface a clear error rather than a silent failure.
JWT decoding shows header and payload claims only. It does not verify signatures or prove a token is trusted, unexpired, or issued by a known party. Treat decoded tokens as readable data, not authentication proof. Hash and checksum tools use browser cryptography APIs for local digests.
Avoid pasting production secrets into any public browser tab on a shared computer. Even though Utilnivo does not upload your snippets, the browser environment itself may retain history or clipboard data.
Formatters aim to preserve meaning while improving readability or compactness. Minify modes remove unnecessary whitespace; pretty-print modes add indentation. Compare tools highlight structural differences so you can review config or API payload changes before deploying. Regex Tester uses JavaScript regular expression semantics, including common flags.
Cron Explainer translates schedule expressions into plain language so you can double-check jobs before production. Timestamp Converter helps move between Unix timestamps and human-readable dates. Use these pages as quick utilities during development, not as a full IDE replacement.
Bookmark the tools you use most and keep sensitive tokens out of screenshots or shared sessions. Clear the page when you finish working with secrets.
Browse the full developer hub or jump into a subcategory from the category chips.
Which tool should you choose?
- Pretty-print data → JSON, XML, SQL, or YAML formatters.
- Tokens and IDs → JWT Decoder or UUID Generator.
- Encoding → Base64 Encoder & Decoder, URL Encoder, or HTML Encoder.
- Diffs → JSON Compare or XML Compare.
Related categories
Frequently asked questions
Is code or token data uploaded?
No. Developer utilities run on your device and do not upload your snippets to Utilnivo servers.
Does JWT decoding verify signatures?
No. Decoding only reads the token parts. Signature verification is not performed.