1vw Blog
Long-form explanations of the calculators and dev tools on 1vw. Strategy guides, theory, and practical tips.
- 2026-05-21 · finance · mortgage
Mortgage Amortization Explained: Why Early Payments Are 80% Interest
A 30-year fixed mortgage at 7% means the first year you pay almost no principal. Here's why, and how extra principal payments break the math in your favor.
- 2026-05-19 · dev · security
JWT vs Session Authentication: A Practical Decision Guide
When to use JWTs vs traditional server-side sessions. The real trade-offs nobody tells you: revocation, latency, blast radius, mobile clients.
- 2026-05-15 · finance · investing
The Rule of 72: How Long to Double Your Money
72 divided by your annual rate equals the years it takes to double. The math behind it and why 7% historical stock returns turn $10k into $1M in 67 years.
- 2026-05-12 · dev · regex
JavaScript Regex Cheatsheet: Patterns You Actually Use
The 30 regex patterns you reach for 95% of the time: email, phone, URL, dates, capture groups, lookaheads. With JavaScript-specific gotchas.
- 2026-05-09 · dev · security
MD5, SHA-256, bcrypt, Argon2: Which Hash Function to Use
A decision tree: use MD5 for non-security checksums, SHA-256 for integrity, bcrypt/Argon2 for passwords. Why each one exists and where it breaks.
- 2026-05-23 · dev · web
URL Encoding 2026: When Percent-Encoding Bites You
Percent-encoding rules from RFC 3986: which characters need escaping, why + means space in forms but not paths, and the encodeURI vs encodeURIComponent trap.
- 2026-05-23 · dev · encoding
Base64 vs URL-Safe Base64: When the Difference Matters
Standard Base64 uses + and /. URL-safe Base64 swaps them for - and _. The two characters that decide whether your JWT, image, or token survives a URL.
- 2026-05-23 · dev · markdown
Markdown Tables: When to Hand-Write vs Use a Generator
Hand-write Markdown tables under 4 columns and 8 rows. Generate above that. The exact syntax, alignment, and the GitHub vs CommonMark gotchas.
- 2026-05-23 · dev · ops
Cron Expressions: Every Pattern You'll Actually Need
The 5 fields, the 7 special characters, and the 12 patterns that cover 95% of cron use. Plus the day-of-week vs day-of-month OR-trap that breaks schedules.
- 2026-05-23 · dev · design
Color Math: Convert HEX, RGB, and HSL in Your Head
HEX is two hex digits per channel. RGB is the same numbers in decimal. HSL is a different model entirely. The conversion math, the shortcuts, and the WCAG contrast math.