Runs in your browser · nothing uploaded

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.

35 tools and counting

Formatters & Validators

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

Encoders & Decoders

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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

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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.JSON ⇄ CSVConvert between JSON arrays and CSV in one click.JSON to TypeScriptGenerate a TypeScript interface from a JSON sample.

Generators

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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.HMAC GeneratorGenerate a keyed-hash message authentication code.Password HasherHash and verify passwords with bcrypt or PBKDF2.

Text & Code

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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.Regex Cheat SheetEvery common regex token, with a plain-English meaning and example.

Network

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DNS LookupLook up A, MX, TXT and other DNS records.HTTP Status CodesSearchable reference for every HTTP status code.CIDR / Subnet CalculatorCalculate network range, netmask and usable hosts from CIDR notation.

Design & Visual

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Open Graph PreviewPreview and generate the meta tags for how a link looks when shared.Favicon GeneratorGenerate every favicon size from one image.CSS Gradient GeneratorBuild a linear or radial gradient and copy the CSS.

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.

Frequently asked questions

Is Appachi Tools free to use?

Yes. Every tool is free forever — no account, no signup, and no usage limits.

Is my data uploaded to a server?

No. Every tool runs entirely in your browser — JSON, tokens, and text you paste are processed locally and never uploaded. The one exception is the DNS Lookup tool, which sends only the domain name you enter to public DNS-over-HTTPS resolvers.

Do I need to create an account?

No. There is no signup or account for any tool — open one and start using it.

How many tools are available, and what kinds?

35 free developer tools across formatters, encoders, converters, generators, text tools and network utilities — including a JSON formatter, regex tester, JWT decoder, Base64 encoder/decoder, and diff checker.