51 tools

Developer tools

Free online developer tools for formatting JSON, decoding JWTs, generating UUIDs, working with HTTP, encoding data, timestamps, hashes, regex, and more. All tools run locally in your browser.

51 ready tools

Runs locally

No signup

Searchable

51 developer tools

JSON FormatterFormat, validate, and sort JSON locally.Open tool

JSON to TypeScriptGenerate TypeScript interfaces from JSON.Open tool

Visual Image DiffCompare two images locally.Open tool

UUID GeneratorGenerate UUIDs locally.Open tool

Hash GeneratorGenerate and compare SHA hashes locally.Open tool

HMAC GeneratorGenerate HMAC signatures locally.Open tool

Security Headers GeneratorGenerate CSP and security headers locally.Open tool

Permissions Policy GeneratorGenerate browser permissions headers locally.Open tool

CSP AnalyzerAnalyze CSP headers and risky directives locally.Open tool

security.txt GeneratorGenerate security.txt disclosure files locally.Open tool

robots.txt GeneratorGenerate robots.txt crawler rules locally.Open tool

humans.txt GeneratorGenerate a humans.txt credits file locally.Open tool

llms.txt GeneratorGenerate llms.txt discovery files locally.Open tool

Open Graph & Meta Tag GeneratorGenerate SEO and social meta tags locally.Open tool

HTTP Header InspectorInspect response headers and security signals locally.Open tool

Timestamp ConverterConvert Unix timestamps locally.Open tool

Cron Expression BuilderBuild, explain, and preview cron schedules locally.Open tool

Base ConverterConvert binary, decimal, hex, and more locally.Open tool

JWT DecoderDecode JWTs locally.Open tool

JWT Claim ExplainerExplain JWT claims locally.Open tool

Base64 Encoder/DecoderEncode and decode Base64 locally.Open tool

HTML EntitiesEncode and decode HTML entities locally.Open tool

HTML/CSS PlaygroundPreview HTML, CSS, JavaScript, and console output locally.Open tool

REST Request TesterTest REST API requests from your browser.Open tool

cURL GeneratorGenerate cURL commands locally.Open tool

OpenAPI ViewerInspect OpenAPI and Swagger specs locally.Open tool

HTTP Status LookupLook up HTTP response codes locally.Open tool

MIME Type LookupLook up MIME types and extensions locally.Open tool

Regex TesterTest regex matches and replacements locally.Open tool

Markdown PreviewPreview and export Markdown locally.Open tool

Markdown to HTMLConvert Markdown to HTML locally.Open tool

Markdown Table GeneratorGenerate Markdown tables locally.Open tool

Markdown TOC GeneratorGenerate Markdown TOCs locally.Open tool

HTML to MarkdownConvert HTML to Markdown locally.Open tool

SVG PreviewPreview, inspect, and export SVG locally.Open tool

XML FormatterFormat and minify XML locally.Open tool

SQL FormatterFormat and minify SQL locally.Open tool

SQL PlaygroundRun SQLite queries locally in your browser.Open tool

SQL Query TesterTest SQL queries against local sample data.Open tool

SQLite PlaygroundRun SQLite examples locally.Open tool

SQL Join PlaygroundPractice SQL JOIN queries locally.Open tool

SQL Schema BuilderDraft and test SQL schemas locally.Open tool

YAML to JSONConvert YAML into JSON locally.Open tool

CSV to JSONConvert CSV to JSON locally.Open tool

JSON to CSVConvert JSON to CSV locally.Open tool

CSV CleanerClean CSV data locally.Open tool

Prompt OptimizerStructure rough AI prompts locally.Open tool

AI Cost CalculatorCalculate custom AI token costs locally.Open tool

Prompt DiffCompare prompt versions locally.Open tool

JSON Schema GeneratorGenerate JSON Schema from JSON locally.Open tool

Markdown Cleaner for AIClean Markdown before AI prompts.Open tool

Guide

About developer tools

Developer tools help with quick format, encode, decode, inspect, and generate tasks that interrupt normal coding work.

Use them for JSON, JWTs, Base64, HTTP status codes, regular expressions, timestamps, UUIDs, hashes, Markdown, SVG, and other browser-safe checks.

FAQ

Developer tools FAQ

Do developer tools upload code or data?

No. Developer utilities are designed to run locally in your browser unless a specific tool clearly states otherwise.

Can I paste private JSON, tokens, or logs?

The tools do not upload your input, but you should still avoid pasting secrets into any website unless you are comfortable with the local browser environment.

Learn

Learn about Developer

Short explanations and guides behind these tools.

What is SVG?Explainer How to compare two imagesGuide What is JSON?Explainer What is Base64 encoding?Explainer JWT explained: how JSON Web Tokens workExplainer What is a UUID?Explainer

Explore more

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