Practical guides for developers — JSON, SQL, TypeScript, HTTP, permissions, accessibility, money in code and building software that handles invoices and tax.
The real differences between CSV and JSON, when each fits, and the conversion traps: leading zeros, dates, encodings and nested data.
How diff tools find changes with the longest common subsequence, how to read unified diff output, and when line diffs mislead you.
Every Markdown element you actually use (headings, lists, links, code, tables) plus common gotchas, flavour differences and how to preview first.
A practical SQL style guide: keyword case, clause layout, joins, aliases, CTEs, commas and comments, with before-and-after examples.
Turn API responses into TypeScript types, handle optional fields, nulls and unions, and learn why types alone don't validate data at runtime.
What WCAG contrast ratios mean, the AA and AAA thresholds for text and UI, how the ratio is calculated and how to fix failing colours.
How Linux permissions work: owner, group, others, rwx, octal like 755 and 644, symbolic mode, setuid and sticky bit, with safe server defaults.
Which HTTP status code to return and when in a REST API: 2xx, 3xx, 4xx and 5xx, common mistakes like 200 for errors, and error response design.
Practical length limits for page titles, meta descriptions, social posts and SMS, how reading time is estimated and how to write to a limit.
What utm_source, utm_medium and utm_campaign mean, naming conventions that keep reports clean, and how to track WhatsApp, email and social links.
What goes wrong when developers build invoicing: float money, VAT rounding, gap-free numbering, immutability, e-invoicing and audit trails.
Why floats break money, how to use integer minor units or decimals, rounding modes, allocating remainders and tests that catch bugs.
Should your app include its own invoicing and accounting, or connect to existing software? Cost, compliance, maintenance and the hybrid approach.
A guide for freelance developers in the UAE and India: invoice contents, VAT or GST, exports of services, milestones and getting paid on time.