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Free Online Developer Tools

A fast, private toolkit for everyday dev work — format JSON, test regex, decode JWTs, convert timestamps and more. No signup, no installs, no data leaving your machine.

25 tools and counting

Formatters & Validators

JSON FormatterFormat, validate, and beautify JSON instantly.SQL FormatterBeautify and format SQL queries for readability.

Encoders & Decoders

Base64 Encode / DecodeEncode and decode Base64, including URL-safe variant.URL Encode / DecodePercent-encode and decode URLs and query strings.JWT DecoderDecode and inspect JSON Web Tokens safely.HTML Entity EncoderEncode and decode HTML entities safely.Image to Base64Convert images to Base64 data URIs in your browser.

Converters

Epoch ConverterConvert Unix timestamps to dates and back.Color ConverterConvert colors between HEX, RGB, HSL and HSV.JSON ⇄ YAMLConvert between JSON and YAML in one click.Number Base ConverterConvert between binary, octal, decimal and hex..env ⇄ JSONConvert between .env files and JSON.

Generators

Cron Expression EditorBuild and explain crontab schedules in plain English.Hash GeneratorGenerate MD5, SHA-1, SHA-256 and SHA-512 hashes.Password GeneratorCreate strong, random passwords with full control.UUID GeneratorGenerate random UUID/GUID v4 and v7 identifiers.QR Code GeneratorTurn any text or URL into a downloadable QR code.Lorem Ipsum GeneratorGenerate placeholder text by paragraphs, sentences or words.

Text & Code

Regex TesterBuild and debug regular expressions with live matching.Diff CheckerCompare two texts and highlight every difference.Markdown EditorWrite Markdown with an instant live preview.Case ConverterConvert text between every common case.Word CounterCount words, characters, sentences and reading time.SlugifyTurn any text into a clean URL slug.

Network

DNS LookupLook up A, MX, TXT and other DNS records.

Why Appachi Tools

Private by default

Your data is processed in your browser. JSON, tokens and text are never uploaded to a server.

Instant & fast

No round-trips, no spinners. Tools react as you type, on desktop and mobile alike.

Free, no signup

Every tool is free forever. No account, no ads in your data, no limits.

From Appachi Tech

The privacy-first developer products we build alongside these tools.

Suvadu

Total recall for your terminal — database-backed shell history with TUI search, analytics and AI-agent monitoring.

Kaval

Guard your ports — a developer-focused port and process manager that shows what's listening and kills what shouldn't be.