Developer Tools
Format SQL, decode JWT tokens, inspect JSON, beautify HTML and JavaScript, test regex, and more — free developer tools for API and backend work.
Best tools to start with
Curated entry points for the strongest developer workflows.
SQL Formatter
Format and beautify SQL queries.
JSON Tree Viewer
Visualize JSON data in an interactive tree structure.
JWT Decoder
Decode and inspect JSON Web Tokens (JWT) without validation.
JSON Path Tester
Test JSONPath expressions against your JSON.
HTML Beautifier
Format and beautify minified or messy HTML code.
Regex Visualizer
Visualize regular expressions as interactive railroad diagrams — understand complex patterns with a clear SVG flowchart, live match testing, and flag explanations.
All Developer Tools
23 free tools — no sign-up required.
Code to Image Converter
Convert code snippets to beautiful images for sharing.
Cron Expression Explainer
Translate cron expressions to plain English — see next run times, validate schedules, and learn cron syntax with live examples.
Cron Expression Generator
Build and decode cron schedule expressions visually — get human-readable descriptions and next run times.
DNS Lookup Tool
Query A, AAAA, MX, TXT, CNAME, NS, and SOA DNS records globally using Cloudflare DoH — for email, SSL, and domain debugging.
Unix Timestamp Converter
Convert Unix epoch timestamps to human-readable dates and vice versa — with timezone support.
HTML Beautifier
Format and beautify minified or messy HTML code.
HTML Minifier
Compress HTML by removing whitespace, comments, and redundant attributes — with size reduction stats.
HTTP Status Code Reference
Searchable reference for all HTTP status codes — with meaning, common causes, and fix recommendations.
IP Address Lookup
Look up geolocation, ISP, ASN, and timezone data for any IPv4 or IPv6 address — with automatic detection of your current IP.
JavaScript Beautifier
Format and beautify minified or messy JavaScript code.
JavaScript Minifier
Compress and minify JavaScript using Terser — with variable mangling, dead-code removal, and size stats.
JSON Path Tester
Test JSONPath expressions against your JSON.
JSON to TypeScript Interface
Convert any JSON object into TypeScript interfaces instantly — handles nested objects, arrays, union types, optional fields, and generics.
JSON Tree Viewer
Visualize JSON data in an interactive tree structure.
JWT Debugger
Decode, inspect, and verify JSON Web Tokens (JWT) locally.
JWT Decoder
Decode and inspect JSON Web Tokens (JWT) without validation.
MD5 Generator
Instantly generate MD5 hashes from any text for checksums and data verification.
React Native Shadow Generator
Generate cross-platform React Native shadow styles — iOS shadowColor/shadowOffset and Android elevation in one StyleSheet object.
Regex Visualizer
Visualize regular expressions as interactive railroad diagrams — understand complex patterns with a clear SVG flowchart, live match testing, and flag explanations.
SHA Hash Generator
Generate SHA-1, SHA-256, SHA-384, and SHA-512 hashes from text instantly in your browser.
SQL Formatter
Format and beautify SQL queries.
User Agent Parser
Decode any User-Agent string — identify browser, engine, OS, device type, and bot classification.
Webhook Tester
Receive, inspect, and debug incoming webhooks in real-time — see headers, body, query params, and method for any HTTP request sent to your unique endpoint.
Why Developer Tools Matter
Developer tools should reduce friction in the middle of debugging, not force you into a separate research project. When a payload is malformed, a query is unreadable, or a token needs quick inspection, the right tool should turn a frustrating moment into a two-second solution.
The strongest pages in this category are built around tasks that appear repeatedly across API work, backend debugging, and service integration: cleaning up SQL queries, inspecting nested JSON, decoding JWT tokens, formatting HTML and JavaScript, and working with timestamps. These are the tools that come up in the middle of real debugging sessions, not idealised tutorials.
This category also connects directly to the converter category for format work, the security category for auth and hashing tasks, and the generator category for UUIDs, test data, and identifiers. When a workflow crosses those boundaries, the related-tool blocks and collection links are there to keep the path clear.
Start with SQL Formatter, JSON Formatter, JSON Tree Viewer, and JWT Decoder if you are new to this category — those four cover the majority of day-to-day API and backend inspection tasks.
Developer Tool Collections
Grouped workflows that connect developer tools to adjacent tasks.
API & Backend Pack
The developer tools you open every day: JWT decoder, JSON formatter, HTTP status codes, cron builder, SQL formatter, and more.
Security & Privacy Kit
Password generators, strength checkers, hash functions, and token decoders — all running entirely in your browser, never touching a server.
Developer Guides & Posts
In-depth guides and tips for getting the most out of developer tools.
Developer FAQ
Common questions about developer tools and how to use them.
Which developer tools should most users start with?
SQL Formatter, JSON Formatter, JSON Tree Viewer, JWT Decoder, and JavaScript or HTML Beautifiers cover the most common debugging and inspection jobs for web developers.
Why are some related tools in other categories?
Real workflows cross category boundaries. A backend debugging session often touches converter, security, and generator tools, so the category hub intentionally links across those boundaries.
Are these tools safe for private payloads or internal code snippets?
Most of the core developer tools on WebToolsPlanet run locally in the browser, which is useful when you are inspecting tokens, JSON payloads, or messy code that should not be pasted into a server-backed app.