Practical guides for common dev tasks
Step-by-step explanations with code examples — covering the things developers look up most often, from parsing tokens to writing cron schedules.
How to Parse a JWT
A practical guide to reading and decoding JSON Web Tokens — understand the three-part structure, decode the header and payload, and know what to check before trusting a token.
Read: How to Parse a JWT →How to Generate Cryptographic Hashes
A practical guide to hashing — understand what hash functions do, the difference between MD5, SHA-1, SHA-256, and SHA-512, and how to generate hashes in JavaScript, Python, and the terminal.
Read: How to Generate Cryptographic Hashes →How to Hash a Password Correctly
A practical guide to storing passwords securely — why plain hashing is wrong, which algorithms to use, how salting works, and what a safe implementation looks like.
Read: How to Hash a Password Correctly →How to Sign API Requests with HMAC
A practical guide to HMAC request signing — what it proves, how to construct a canonical request, sign it with a shared secret, and verify it on the server.
Read: How to Sign API Requests with HMAC →How OAuth 2.0 Works
A practical guide to OAuth 2.0 — the authorization code flow, PKCE, tokens, scopes, and when to use each grant type.
Read: How OAuth 2.0 Works →How to Validate JSON
A practical guide to checking JSON for syntax errors, understanding common mistakes, and formatting it for readability.
Read: How to Validate JSON →How to Read and Write CSV
A practical guide to the CSV format — structure rules, edge cases with quotes and commas, parsing in JavaScript and Python, and common pitfalls.
Read: How to Read and Write CSV →How to Convert JSON to YAML (and Back)
A practical guide to converting between JSON and YAML — format differences, conversion rules, gotchas with types, and code examples.
Read: How to Convert JSON to YAML (and Back) →Cron Expression Examples
A reference guide to cron syntax with common schedule patterns — from every minute to complex multi-field expressions — with plain-English explanations.
Read: Cron Expression Examples →How to Convert Units
A practical guide to unit conversion — understand the metric and imperial systems, common conversion factors, and how to convert length, weight, temperature, and volume accurately.
Read: How to Convert Units →How chmod and File Permissions Work
A practical guide to Unix file permissions — reading the permission string, understanding octal notation, using chmod and chown, and common secure permission patterns.
Read: How chmod and File Permissions Work →How to Read HTTP Headers
A practical guide to HTTP headers — request vs response headers, what the most important ones mean, how to inspect them in the browser and curl, and security headers you should be setting.
Read: How to Read HTTP Headers →How to Encode and Decode Base64
A practical guide to Base64 encoding and decoding — understand when and why to use it, how to handle Unicode, and how to do it in JavaScript, Python, and the command line.
Read: How to Encode and Decode Base64 →How to URL Encode and Decode
A practical guide to percent-encoding — understand which characters need encoding, how the % notation works, and how to encode and decode URLs in JavaScript, Python, and the terminal.
Read: How to URL Encode and Decode →How HTML Escaping Works
A practical guide to HTML escaping — why it matters for security, which characters to escape, when to use it, and how XSS happens when you skip it.
Read: How HTML Escaping Works →How to Convert an Epoch (Unix) Timestamp
A practical guide to Unix epoch timestamps — what they are, how to convert them to human-readable dates, and how to work with them in JavaScript, Python, and the command line.
Read: How to Convert an Epoch (Unix) Timestamp →Understanding Timezones and UTC Offsets
A practical guide to timezones — understand UTC, IANA timezone names, UTC offsets, Daylight Saving Time, and how to reliably work with times across zones in code.
Read: Understanding Timezones and UTC Offsets →Working with Dates Across Time Zones in JavaScript
A practical guide to JavaScript dates — the Date object, UTC vs local time, formatting, parsing, and how to avoid the most common time zone bugs.
Read: Working with Dates Across Time Zones in JavaScript →How to Use Regular Expressions
A practical guide to regular expressions — learn the core syntax, common patterns, and how to write regex for real-world tasks like email validation, URL matching, and log parsing.
Read: How to Use Regular Expressions →How to Read a Diff
A practical guide to reading unified diffs — understand the +/- notation, hunk headers, file headers, and how diffs appear in git, pull requests, and patch files.
Read: How to Read a Diff →How to Write a Regex Pattern Step by Step
A practical guide to building regular expressions from scratch — breaking down the problem, choosing the right tokens, testing incrementally, and avoiding common traps.
Read: How to Write a Regex Pattern Step by Step →How to Use Git: Core Workflows
A practical guide to everyday Git usage — committing, branching, merging, resolving conflicts, and keeping a clean history.
Read: How to Use Git: Core Workflows →