Developer toolbox

Handy tools, no clutter.

A fast, private collection of everyday utilities for developers and IT folks. Everything runs in your browser.

106 toolsPrivate — runs in your browserWorks offline (PWA)TH / ENShareable links

Explore the toolkit

Developer cheatsheets

Quick, searchable references for everyday commands and syntax — with in-depth recipes, examples, and troubleshooting on the deeper sheets.

Guided playbooks

Start from a task — follow the steps, jump to the right tools, and collect results as you go.

Guided learning paths

Topic tracks that tie concepts, references, tools, and a hands-on task together — a route through the toolkit, not just a list.

Coding exercises

Short problems with hidden tests — write code, run it, and see it graded right in your browser. Nothing is uploaded.

Language quizzes

Quick checks for languages that don't run in the browser — predict the output, pick the right answer, or fill the blank. Auto-graded, nothing uploaded.

Visualizations

Every interactive figure across the cheat sheets in one place — animated 2D explainers and orbitable 3D simulations you can step through.

Dev glossary (EN ↔ TH)

Developer concepts explained in both English and Thai — search a term you hit in the docs and read it in plain ไทย.

What do you have?

Pick what you're holding and see every tool that works with it — no need to know its name.

Recommended workbenches

Crypto

Token generator

Generate a random, secure token with a custom length and character sets.

UUID generator

Generate random RFC 4122 version-4 UUIDs, with options for quantity, case, and hyphens.

Hash text

Hash text with SHA-1, SHA-256, SHA-384, and SHA-512.

HMAC generator

Compute an HMAC signature from a message and a secret key.

ULID generator

Generate sortable, unique ULID identifiers.

Bcrypt

Hash a password with bcrypt, or check a password against a hash.

BIP39 mnemonic generator

Generate a BIP39 mnemonic seed phrase.

RSA key pair generator

Generate an RSA public/private key pair (PEM).

Password strength analyser

Estimate a password's entropy and crack time.

Text encryption

Encrypt and decrypt text with AES-GCM and a passphrase.

PDF signature checker

Check whether a PDF contains a digital signature.

PDF signature & annotator

New

Stamp a visual signature, text, date or check mark onto a PDF. Runs entirely in your browser — the file is never uploaded. This is a visual stamp, not a cryptographic digital signature.

Certificate decoder

New

Decode an X.509 certificate or CSR: subject, validity, SANs, key, and fingerprints.

Converter

Case converter

Convert text between camelCase, snake_case, kebab-case, and more.

Base64 string converter

Encode and decode text to and from Base64 (UTF-8 safe).

Base64 file converter

Encode a file into a Base64 data URL.

Integer base converter

Convert numbers between bases — binary, octal, decimal, hex, and any base 2–36.

Roman numeral converter

Convert numbers to Roman numerals and back (1–3999).

Temperature converter

Convert between Celsius, Fahrenheit, and Kelvin.

Color converter

Convert a color between HEX, RGB, HSL, HSV, and CMYK.

Color contrast checker

Check the WCAG contrast ratio between a text and background color.

JSON to TypeScript

Generate TypeScript interfaces from a JSON sample.

Date-time converter

Convert between ISO, Unix timestamps, UTC, and local time.

Buddhist Era ↔ Gregorian

New

Convert dates between the Thai Buddhist calendar (พ.ศ.) and the Gregorian calendar (ค.ศ.).

Thai Baht to words

New

Read a Baht amount aloud in Thai words (อ่านจำนวนเงินเป็นตัวอักษร) for invoices and cheques.

Text to NATO alphabet

Spell text out using the NATO phonetic alphabet.

Text to binary

Convert text to its binary representation and back.

Text to Unicode

Convert text to U+ code points and back.

YAML to JSON

Convert YAML into formatted JSON.

JSON to YAML

Convert JSON into YAML.

Markdown to HTML

Render Markdown to HTML with a live preview.

TOML to JSON

Convert TOML into JSON.

JSON to TOML

Convert JSON into TOML.

YAML to TOML

Convert YAML into TOML.

TOML to YAML

Convert TOML into YAML.

XML to JSON

Convert XML into JSON.

JSON to XML

Convert JSON into XML.

Web

URL encoder / decoder

Encode or decode a string for safe use in a URL.

URL parser

Break a URL into its parts and query parameters.

curl to code

Convert a curl command into fetch, axios, or Python requests code.

CSS generator

Visually build box-shadow and gradient CSS.

Slugify string

Turn text into a clean, URL-friendly slug.

HTML entities encoder / decoder

Escape or unescape HTML entities in a string.

Basic auth generator

Build an HTTP Authorization header from a username and password.

JWT parser

Decode and inspect a JSON Web Token’s header and payload (no signature check).

JWT signer / verifier

Decode, verify (HS256/RS256), and sign JSON Web Tokens locally for testing.

CSP builder

Build and audit a Content-Security-Policy header, directive by directive.

HTTP status codes

Search a reference of common HTTP status codes.

Meta tag generator

Generate Open Graph and Twitter meta tags for your page.

Keycode info

Show the JavaScript key, code, and keyCode for any pressed key.

Device information

Inspect your screen, viewport, and browser details.

Safelink decoder

Unwrap Outlook SafeLinks and similar URL redirectors.

OTP (TOTP) generator

Generate time-based one-time passwords from a base32 secret.

User-agent parser

Parse a user-agent string into browser, OS, and device.

Email normalizer

Normalize email addresses (strip +tags, Gmail dots).

MIME types

Look up MIME types by file extension.

HTML WYSIWYG editor

Edit rich text and get the HTML output.

HAR viewer

Inspect a HAR (HTTP Archive) export from your browser's network tab — requests, status, size, timing and a waterfall.

Images

QR code generator

Generate a QR code from text or a URL, with custom colors.

PromptPay QR generator

New

Create a Thai PromptPay QR from a phone number or national/tax ID, with an optional amount.

SVG placeholder generator

Generate a lightweight SVG placeholder image.

WiFi QR code generator

Create a QR code that connects devices to a WiFi network.

Camera recorder

Record video from your webcam and download it.

EXIF viewer & remover

New

View an image's EXIF metadata (including GPS) and download a metadata-free copy. Runs entirely in your browser.

Image format converter

New

Convert images between PNG, JPEG, WebP and AVIF, with optional resizing and quality control. Runs entirely in your browser.

Development

Chmod calculator

Build a Unix file-permission value (octal + symbolic) with checkboxes.

Mock data generator

Generate realistic fake data (names, emails, UUIDs…) as JSON.

Random port generator

Generate random port numbers above the well-known range (1024–65535).

JSON minify / prettify

Minify or prettify a JSON document.

JSON to CSV

Convert a JSON array of objects into CSV.

SQL prettify

Format and beautify an SQL query.

Crontab describer

Describe a cron expression in plain language.

JSON diff

Compare two JSON documents and list the differences.

Regex tester

Test a regular expression against a string and see matches.

YAML viewer

Validate and normalise a YAML document.

XML formatter

Format and indent an XML document.

JSON viewer

Explore JSON as a collapsible tree, with formatting and validation.

OpenAPI / JSON Schema validator

New

Validate and inspect an OpenAPI spec or JSON Schema locally, in JSON or YAML.

docker run → docker-compose

Convert a docker run command into a docker-compose service.

Webhook signature tester

New

Compute and verify HMAC webhook signatures for GitHub, Stripe, Slack, or a custom scheme — locally, no network.

.env file parser

New

Parse a .env file into a key/value table, flag duplicate keys and secrets, and export JSON.

Network

MAC address generator

Generate random, locally-administered MAC addresses.

IPv4 address converter

Convert an IPv4 address to decimal, hex, binary, and IPv6.

IPv4 subnet calculator

Calculate network, broadcast, mask and host range from a CIDR.

IPv4 range expander

Find the smallest CIDR block that covers a start–end IPv4 range.

IPv6 ULA generator

Generate a unique local IPv6 address prefix (RFC 4193).

MAC address lookup

Look up the vendor for a MAC address (OUI).

Text

Lorem ipsum generator

Generate placeholder paragraphs of lorem ipsum text.

Text statistics

Count characters, words, lines, and sentences in your text.

List converter

Sort, deduplicate, trim, and transform a list (one item per line).

String obfuscator

Mask the middle of a string, keeping a few characters visible.

Numeronym generator

Create numeronyms like i18n from words.

Duplicate lines remover

Remove duplicate lines from a block of text, with options for case, trimming, and empty lines.

Text diff

Compare two blocks of text line by line.

ASCII art text

Turn text into ASCII art (FIGlet).

Emoji picker

Search emoji and click to copy.

Math

Percentage calculator

Common percentage calculations: percent of a value, ratios, and change.

ETA calculator

Estimate the remaining time and finish time of a task in progress.

Math evaluator

Evaluate a mathematical expression.

Measurement

Chronometer

A simple stopwatch with lap times.

Benchmark builder

Compare measurements and see relative ratios (lower is faster).

Data

IBAN validator & parser

Validate and break down an IBAN.

Thai national ID validator

New

Check a 13-digit Thai national ID (เลขบัตรประชาชน) / personal tax ID and decode it.

Phone parser & formatter

Parse and format a phone number to E.164, national, and international.

CSV viewer & converter

New

View, validate, and convert CSV/TSV to JSON and back, with a custom delimiter.

Text compressor

New

Compress or decompress text with gzip/deflate, with Base64 output and a size readout.