Developer Tools — Base64, Hashing, UUIDs & Regex
Guides to Base64, URL encoding, hashing, UUIDs, timestamps, regex, and mock data.
How to POST JSON with curl: The Practical Guide
Send JSON from the command line with curl — the Content-Type header, -d vs --json, posting a file, auth headers, and the quoting mistakes that cause most errors.
nanoid vs UUID vs ULID: Choosing an ID Format
Not every ID should be a UUID. Compare UUID v4/v7, ULID, and nanoid on size, sortability, URL-friendliness, and database performance — and pick the right one for your use case.
Random JSON Generator — Create Mock Data for Testing and Development
Generate realistic random JSON mock data for tests, UI prototyping, and database seeding. 60+ field types, formula fields, linked tables, and code examples using gofakeit (Go), Faker.js (JavaScript), and Faker (Python).
llms.txt Explained: The AI Crawler Standard and What It Actually Does
What llms.txt is, how it differs from robots.txt and sitemaps, what Google actually said about it for SEO, and how it fits alongside JSON-LD.
Building the Frontend Before the Backend Exists — a JSON Mocking Workflow
How to build and demo a UI against a backend that doesn't exist yet — a mock JSON contract, intercepting fetch calls with MSW or json-server, and swapping to the real API with zero component changes.
Feature Flags: The JSON Powering LaunchDarkly & Unleash
How feature flag platforms structure flag payloads as JSON — targeting rules, percentage rollouts and variant assignment — and how to read one in your own code.
UUID v4 vs UUID v7 — Which Should You Use for Database Primary Keys?
Understand the difference between UUID v4 (random) and UUID v7 (time-sortable), why random UUIDs hurt database performance, and how to choose the right version.
Regular Expressions Explained — JavaScript vs Go RE2 Differences
Learn regular expressions — patterns, flags, capture groups, and lookaheads. Understand the key differences between JavaScript PCRE and Go's RE2 engine.
Unix Timestamps Explained — Convert and Format Dates in Every Language
Learn what Unix timestamps are, how to convert them to human-readable dates, and format them in Go, Python, JavaScript, PHP, Java, and Rust.
How to Convert cURL Commands to Go, Python, and JavaScript Code
Convert cURL commands to idiomatic HTTP client code in Go, Python, JavaScript, PHP, and Ruby. Learn the mapping between cURL flags and language HTTP libraries.
SHA-256, SHA-512, and HMAC Explained — Hash Functions for Every Language
Learn SHA-256, SHA-512 hashing and HMAC signatures. Code examples for Go, Python, JavaScript, Java, and Rust. Understand when to use each algorithm.
URL Encoding Explained — Query, Path, and Form Encoding
Learn URL encoding — encodeURIComponent, path encoding, and form encoding (application/x-www-form-urlencoded). Code examples for Go, Python, JavaScript, PHP, and Java.
Base64 Encoding Explained — Standard, URL-safe, and Raw Variants
Learn Base64 encoding and decoding — Standard, URL-safe, and Raw variants. Code examples for Go, Python, JavaScript, Java, and Rust.