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.

Validate, lint, and visualize Docker Compose files — and make sense of container networking.

Validate manifests, calculate resource requests/limits, and make sense of Kubernetes YAML.

Independent tools for the test data every project eventually needs — unique IDs, strong passwords, placeholder text — plus a way to check the strength of a password you already have. All run entirely in your browser.

Format, validate, diff, minify, convert, query, and schema-generate/validate JSON — ten tools for the format everything speaks. All run entirely in your browser.

Base64, URL, HTML, hex, and ASCII encoding and decoding, plus query string and full URL parsing, building, inspection, Unicode analysis, and string-literal escaping — sixteen 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, build, and secure them. All eight tools run entirely in your browser; nothing you paste is ever sent anywhere.

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

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

Format, validate, minify, diff, index-advise, and explain SQL — six tools covering readability, correctness, schema changes, 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 — five 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, diff, explore relationships, and merge or compare Helm values for Kubernetes manifests — seven tools covering correctness, readability, and resource planning. All run entirely in your browser.

Validate and format YAML — syntax errors, duplicate keys, parser-version gotchas, and consistent indentation — schema-agnostic, for any YAML file. All run entirely in your browser.

Parse and build ARNs, generate, review, simulate, and minify IAM policies, validate tag policies, look up Regions, and validate CloudFormation templates — nine tools for everyday AWS work. All run entirely in your browser.

Format and validate GraphQL queries, mutations, and SDL schemas with the real reference parser. All run entirely in your browser.

Computer science fundamentals for practicing engineers — algorithm complexity, performance analysis, and scalability, with interactive tools and practical examples. All run entirely in your browser.

How the structures underneath every algorithm actually work — arrays, hash tables, trees, and more, visualized step by step. All run entirely in your browser.

The numbers behind systems that hold up under load — caching, capacity, and the metrics worth actually tracking. All run entirely in your browser.

Throughput Calculator

Estimate system capacity from requests/sec, latency, and instance count, via Little's Law.

Database Index Cost Estimator

Simulate whether an index's read savings outweigh its write overhead, in comparable operation counts.

Cache Hit Ratio Calculator

Calculate hit rate and miss rate from total requests and cache hits.

Trie Visualizer

Insert, search, delete, and autocomplete on a real trie — the structure behind search-box suggestions.

Heap Visualizer

Insert, extract, and peek on a real min-heap or max-heap, with every sift-up and sift-down traced.

Binary Search Tree Visualizer

Insert, search, and delete on a real BST — including the tricky two-children delete case.