Free Developer Tools (42)
42 free online developer tools. Encode/decode, format, test, diagram, generate. All browser-based, no signup, no tracking.
Base64 Encoder/Decoder
Encode or decode Base64 text and files online. Free, instant, 100% private — all processing happens in your browser.
AI Code Explainer
Paste any code and get a plain-English explanation. Supports all languages. DeepSeek AI.
Diff Checker
Compare two texts side-by-side. AI explains differences.
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 hashes.
JWT Decoder
Decode JWT tokens. View header, payload, signature.
README Generator
Create professional GitHub README files from a description. Includes badges, install, usage, license. DeepSeek AI.
Regex Explainer
Paste any regex and get a human-readable breakdown — plain English, component table, use cases, and edge cases. DeepSeek
Regex Tester
Test regex patterns. AI generates regex from plain English.
SQL Query Generator
Generate SQL queries from plain English. Supports MySQL, PostgreSQL, SQLite, SQL Server.
URL Encoder/Decoder
URL encode or decode strings for safe web usage. Free, instant, 100% private — all in your browser.
UUID Generator
Generate UUID v1, v4. Batch generate multiple UUIDs.
JSON Pretty Print
Format and beautify JSON data. Validate, minify, sort keys. See errors with line numbers. Free, instant, private.
JSON Validator
Validate JSON with detailed error messages. Shows JSON structure tree with keys, types, depth. Also validates JSONL.
CSS Minifier
Minify CSS: remove comments, whitespace, last semicolons. See size comparison and compression %. Free, instant.
JavaScript Minifier
Minify JavaScript: remove comments, whitespace. See size comparison. Free, instant, private.
HTML Minifier
Minify HTML: remove comments, whitespace between tags. See compression stats. Free, instant, private.
HTML Entity Encoder
Encode/decode HTML entities — angle brackets, ampersands, quotes to entities and back. Full HTML entity reference table.
Unicode Analyzer
Inspect Unicode characters. See code point, UTF-8/UTF-16 bytes, HTML entity, URL encoding, character name.
Cron Expression Parser
Parse cron expressions to human-readable description. Show next N execution times. Build cron with visual builder.
MIME Type Lookup
Search/browse IANA MIME types by file extension or type. Full reference table of common MIME types and categories.
HTTP Status Codes
Browse HTTP status codes by category (1xx-5xx). Search by code. Each shows reason phrase, description, use cases.
HTML Preview
Paste HTML code, see live rendered preview in sandboxed iframe. Includes basic CSS reset. Copy rendered HTML.
Color Converter
Convert colors between HEX, RGB, HSL, HSV, CMYK formats. Color picker with live preview. Color harmonies generator.
.gitignore Generator
Generate .gitignore files for any tech stack. Select languages, frameworks, editors. Copy or download.
DNS Lookup
Look up DNS records for any domain. A, AAAA, MX, CNAME, TXT, NS, SOA. Uses Google DNS-over-HTTPS.
WHOIS Lookup
Look up domain registration info using RDAP. Find registrar, creation date, expiry, nameservers, domain status.
IP Info
Look up IP address information: geolocation, ISP, timezone, ASN. Auto-detect your IP or query any IP.
SSL Checker
Check SSL certificate details. Issuer, validity dates, days remaining, SANs, certificate chain info.
cURL Command Builder
Build cURL commands visually. HTTP method, URL, headers, body, flags. Live command output. Copy.
API Tester
Test REST APIs directly in browser. Send HTTP requests, view response status, headers, body. Auto-format JSON.
Regex Visualizer
Visualize and explain regex. Highlighted matches, capture groups table, plain-English explanations, cheat sheet.
Markdown Table Generator
Create and edit Markdown tables visually. Click cells to edit, set alignment, add/remove rows. Copy output.
SQL Beautifier
Format SQL queries with customizable indentation and keyword casing. SELECT, INSERT, UPDATE, DELETE, CREATE TABLE.
Flowchart Maker
Draw flowcharts and process diagrams from text using Mermaid syntax. Live preview, export as PNG/SVG. Free, private.
ERD Diagram Maker
Draw entity relationship diagrams from text using Mermaid syntax. Define entities, attributes, relationships. Export PNG
Sequence Diagram Maker
Draw UML sequence diagrams from text using Mermaid syntax. Actors, participants, messages, notes. Export PNG/SVG.
Mind Map Maker
Create mind maps and brainstorming diagrams from text. Hierarchical indentation becomes a visual map. Export PNG/SVG.
Markdown to HTML Converter
Convert Markdown to clean HTML with live preview. GitHub-flavored Markdown — tables, code blocks, task lists. Free, priv
Text Diff Checker
Compare two texts and see differences highlighted line-by-line. Word-level diff, side-by-side or unified view. Free, pri
PPTX Generator
Create PowerPoint presentations in your browser. Add slides with titles and bullet points. Download as .pptx file. Free,
iCal Generator
Create iCal (.ics) calendar event files. Set title, date, time, location, description, and reminders. Compatible with Go
vCard Generator
Create vCard (.vcf) digital business cards. Name, phone, email, address, website. Compatible with iOS, Android, Outlook.