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Developer Tools
Everyday utilities for developers, engineers, and technical teams.
Open one of the developer tools that matches your immediate task, then move into related tools only if you need a second step.
19
19 tools
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Browse all Developer Tools
Use this list to jump straight into the exact developer tools task you need without sorting through unrelated tools first.
JSON Formatter & Validator
Format, beautify, and validate JSON data with syntax highlighting and error detection.
Base64 Encode / Decode
Encode text to Base64 or decode Base64 strings back to plain text instantly.
UUID Generator
Generate random UUID v4 identifiers for databases, APIs, and testing workflows.
JWT Decoder
Decode and inspect JSON Web Token headers and payloads without sending them to a server.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa.
Regex Tester
Test regular expressions against sample text with real-time match highlighting.
Cron Expression Generator
Build and explain cron schedule expressions with a visual interface.
Diff Checker
Compare two blocks of text side by side and highlight the differences.
Markdown to HTML
Convert Markdown text to clean HTML with a live preview.
Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes from text input in your browser.
HTML Minifier
Minify HTML by removing comments, whitespace, and optional quotes for smaller pages and faster loading.
CSS Minifier
Minify CSS by stripping comments, blank lines, and excess whitespace to ship smaller stylesheets.
JavaScript Minifier
Minify JavaScript by removing comments and unnecessary whitespace for faster page loads.
URL Encoder / Decoder
Encode or decode URL components and full URLs (percent-encoding) for safe links, query strings, and APIs.
Credit Card Validator
Validate credit card numbers using the Luhn checksum and detect the card brand (Visa, Mastercard, Amex, Discover, JCB).
HTTP Headers Checker
Inspect HTTP response status, redirect chain, and security headers for any public URL — including HSTS, CSP, and X-Frame-Options.
DNS Records Lookup
Look up A, AAAA, MX, TXT, NS, CNAME, SOA, and CAA DNS records for any domain using public Cloudflare and Google resolvers.
WHOIS Lookup
Run a public WHOIS / RDAP lookup on any domain to see registrar, registration dates, expiration, status flags, and nameservers.
SSL Certificate Checker
Inspect a domain's SSL/TLS certificate chain, expiry date, issuer, fingerprint, and protocol — useful for catching expiring or misconfigured certs.
Categories
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Need a different workflow? Move to a nearby category for related text, image, PDF, or SEO tasks.
Text Tools
Fast writing and cleanup tools for creators, students, and marketers.
Image Tools
Compress and convert images without sending your files anywhere else unless needed.
PDF Tools
Simple PDF workflows designed for speed, clarity, and repeat use.
SEO Tools
Practical site and metadata helpers built for clean search-focused workflows.
Generators
Quickly generate passwords, QR codes, legal pages, invoices, and more.
Converters
Convert files and data between formats directly in the browser.
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Developer Tools FAQ
Quick answers about this developer tools category and where to begin.
What can you do with Developer Tools?
Developer Tools help visitors solve practical tasks quickly. Everyday utilities for developers, engineers, and technical teams.
Which developer tools should I start with?
Start with JSON Formatter & Validator if you want a strong first option, then move into related tools based on the next step in your workflow.
Are these developer tools free to use?
Yes. The developer tools on FreeSEOTools.com are designed for fast browser-based use without account friction.