Quick access to the tools
Format, test & debug backend tools in seconds
All tools
JSON Formatter & Validator
Format and validate JSON instantly
Base64 Encode / Decode
Encode and decode Base64 data
URL Encode / Decode
Safely encode or decode URLs
UUID Generator
Generate unique identifiers quickly
Regex Tester
Test and debug regex patterns
JSON to Code
Convert JSON into usable code
Cron Expression Parser
Decode and understand cron schedules
API Response Tester
Test and inspect API responses
SSL/TLS Checker
Inspect and verify SSL certificate details
Security Headers Analyzer
Audit HTTP security headers instantly
JWT Decoder
Decode and inspect JWT tokens with ease
Password Strength Checker
Evaluate password strength in real time
Hash Generator
Generate MD5, SHA, and other hash values
CSP Evaluator
Validate and debug Content Security Policies
Certificate Decoder
Parse and decode X.509 certificates
CORS Tester
Check and debug cross-origin request settings
Timestamp Converter
Convert between Unix and readable timestamps
Diff Checker
Spot differences between two text blocks
Markdown Preview
Render and preview Markdown in real time
Number Base Converter
Switch between binary, hex, decimal and more
QR Code Generator
Turn any URL or text into a scannable QR code
Lorem Ipsum Generator
Generate placeholder text for your layouts
DNS Lookup
Query DNS records for any domain
WHOIS Lookup
Fetch registration info for any domain
IP Geolocation
Locate any IP address on the map
Subnet Calculator
Calculate subnets, masks, and IP ranges
Ping / Port Checker
Check host reachability and open ports
SEO Analyzer
Audit on-page SEO for any URL
Open Graph Preview
See how your page looks when shared
Sitemap Validator
Validate and inspect XML sitemaps
Robots.txt Tester
Test crawl rules in your robots.txt file
Page Speed Analyzer
Measure and diagnose page load performance
YAML/JSON/TOML Converter
Convert between config file formats instantly
.env Validator
Lint and validate your environment variable files
HTTP Status Code Reference
Look up what every HTTP status code means
Chmod Calculator
Calculate Unix file permissions visually
Uptime Checker
Monitor and verify site availability
Meta Tag Generator
Build SEO and social meta tags quickly
Color Palette Generator
Create harmonious color palettes instantly
CSS Unit Converter
Convert px, rem, em, and viewport units
Build Analyzer
Analyze and break down your app build details
Build Distribute
Share builds with testers via link or QR
Manifest Viewer
Inspect app manifest files at a glance
Provisioning Profile Inspector
Read and decode provisioning profiles
DMARC/SPF/DKIM Checker
Verify email authentication DNS records
Email Header Analyzer
Parse and debug raw email headers
MX Record Checker
Look up mail exchange records for any domain
Developer tools, all in one place
BuildStudio hosts 90+ free developer tools covering the daily debugging stack: JSON formatting, regex testing, JWT decoding, API testing, DNS + WHOIS lookups, hash generation, SSL inspection, SEO audits, mobile build analysis, Unix timestamp conversion, and more. Every tool runs in your browser — no signup, no install, no usage limits.
The catalog is organized by category:
- Backend & API — JSON formatter, regex tester, JWT decoder, UUID/GUID generator, Base64 encode/decode, URL encoder, cron parser, API tester.
- Converters — Unix timestamp converter, hex/binary/decimal converter, diff checker, QR code generator, Markdown preview, Lorem Ipsum generator.
- DevOps — chmod calculator, YAML/JSON/TOML converter, HTTP status code reference, website uptime checker, .env validator.
- DNS & Network — DNS lookup, WHOIS lookup, IP geolocation, port checker, subnet calculator.
- Email — MX record checker, email header analyzer (trace SPF/DKIM/DMARC).
- Frontend — color palette generator, CSS unit converter (px to rem), meta tag generator.
- Mobile — APK/IPA build analyzer, iOS UDID finder, build distribution.
- Security — hash generator (MD5, SHA-256), SSL/TLS checker, certificate decoder, CORS tester, CSP evaluator, password strength checker, security headers scanner.
- SEO — SEO analyzer, page speed test, sitemap validator, robots.txt tester, Open Graph preview.
Why BuildStudio instead of jsonformatter.org, regex101, jwt.io?
Individual tool sites do one thing well. BuildStudio does them all in a consistent, ad-free, account-free environment:
- No ads. Most single-tool sites monetize with intrusive ads; we don't.
- No signup. Every tool works immediately on first visit.
- No data sent to servers for the security-sensitive ones (JWT, hash, Base64, regex) — all runs client-side.
- One bookmark. Stop curating a folder of 30 tool sites.
- Fast. Mobile PageSpeed 98, LCP under 2 seconds.
- Dark mode across all tools. Keyboard shortcuts where it matters.
- Mobile-specific tools nobody else has — APK/IPA analyzer, iOS UDID finder, one-link build distribution.
Frequently Asked Questions
Are BuildStudio's developer tools really free?
Yes — completely free, no signup, no usage limits, no paywall. 90+ tools covering JSON, regex, API testing, JWT, hashing, DNS, SSL, SEO and mobile app distribution. Ad-free. Built by devs for devs.
Do these tools run in the browser or send my data to a server?
Almost all run 100% client-side — JSON formatter, regex tester, JWT decoder, hash generator, Base64, URL encode, UUID. Data never leaves your browser. Network-dependent tools (DNS, WHOIS, uptime, page speed) make server calls, clearly labelled on each tool page.
How do BuildStudio's free dev tools compare to jsonformatter.org, regex101 or jwt.io?
Same quality, unified home. You don't need to bookmark 20 different tool sites — all the common ones live here with consistent UI, no ads, and shared features (theme, keyboard shortcuts, share links). Plus mobile-specific tools (APK analyzer, IPA distribute) you won't find elsewhere.
Are these tools open source?
Not currently — BuildStudio is a product, not an OSS project. But every tool runs in your browser where the code is inspectable (View Source). No obfuscated telemetry, no data collection on tool usage.
Which developer tool should I bookmark first?
Top 5 for daily dev work: **JSON Formatter** (validate + beautify), **Regex Tester** (live match + explain), **JWT Decoder** (inspect tokens), **API Tester** (Postman alternative), **UUID Generator** (v4/v7). Everything else is there when you need it.
Smarter quality checks. Faster deployments.
Better apps.
