Free tools for developers

The most-searched category on DevTools Hub — URL encoding, decoding, and Base64 conversions.

The single biggest source of search traffic — decoding claims, checking expiration, and JWT security.

Validating and formatting SQL syntax across Postgres, MySQL, and more.

Testing and building JavaScript regular expressions without leaving the browser.

Three independent generators for the test data every project eventually needs — unique IDs, strong passwords, and placeholder text. All run entirely in your browser.

Format, validate, diff, minify, and convert JSON — six tools for the format everything speaks. All run entirely in your browser.

Base64, URL, and HTML encoding and decoding, plus query string and full URL parsing, building, and inspection — eleven tools for the encodings that show up constantly in web development. All run entirely in your browser.

Timestamps, timezones, and cron schedules — five tools for the two date-and-time problems every backend eventually runs into. All run entirely in your browser.

Everything for working with JSON Web Tokens, in one place — decode, understand, verify, and build them. All six tools run entirely in your browser; nothing you paste is ever sent anywhere.

MD5, SHA, checksums, and HMAC — five tools for hashing text, verifying files, and signing messages. All run entirely in your browser.

Build, test, visualize, and debug JavaScript regular expressions — five tools covering the whole regex workflow. All run entirely in your browser.

Format, validate, minify SQL, and find the real bottleneck in a query plan — four tools covering readability, correctness, and performance. All run entirely in your browser.

View, validate, diff, and put an OpenAPI/Swagger document to work — five tools covering the full spec lifecycle. All run entirely in your browser.

Validate, lint, format, and visualize Docker Compose files and Dockerfiles — four tools covering the whole Docker workflow. All run entirely in your browser.

Validate, visualize, lint, and audit secrets in GitHub Actions workflows — four tools covering correctness and security. All run entirely in your browser.

Validate, diff, and convert .env files — four tools for the dotenv format's real parsing rules and the gotchas that fail silently. All run entirely in your browser.

Validate, format, calculate resources, and diff Kubernetes manifests — four tools covering correctness, readability, and resource planning. All run entirely in your browser.

URL Inspector

Parse a URL, audit its encoding, and surface phishing and redirect red flags.

Query Parameter Builder

Build a query string from key/value rows or a JSON object.

URL Builder

Visually build a URL from protocol, host, path, query params, and fragment.

URL Parser

Break a URL down into protocol, host, port, path, query, and fragment.

Query String Parser

Break a URL's query string into individual parameters, or export as JSON.

K8s Diff

Compare two Kubernetes manifests field-by-field, matched by resource identity, with server-managed noise stripped by default.