Learn the stuff
they don't teach in school
Real-world guides on taxes, business, code, and design — written by people who actually do this for a living. Updated for 2026.
Tax & Finance
Taxes, investing, retirement, and side hustle math
Self-Employment Tax 2026: Stop Overpaying
Freelancers: you're probably paying more SE tax than you need to. Here's how to calculate it right, claim every deduction, and avoid those nasty quarterly penalties.
Mortgage Amortization: Where Your Money Actually Goes
Spoiler: for the first 5 years, almost all your payment is interest. Here's how to flip that equation and build equity faster without refinancing.
Crypto Taxes in 2026: What the IRS Actually Knows
The IRS gets Form 1099-DA now. Here's how to calculate capital gains, handle DeFi and swaps, and avoid the #1 mistake that triggers audits.
401(k) vs Roth IRA: The Honest Answer
Everyone says "it depends." Here's what it actually depends on — your tax bracket now vs. in retirement, employer match, and the one scenario where Roth always wins.
Compound Interest: Why Starting Early Beats Saving More
Someone who saves $200/month from age 25 ends up with more than someone saving $500/month from age 40. The math is wild — and it works against you with debt too.
W-2 vs 1099: That $100K Contract Is Really $72K
The 25-40% pay gap no one talks about. Health insurance, retirement match, PTO, unemployment — when you add it all up, that contractor rate isn't what it seems.
1099-K Changes: The $600 Threshold Hits Everyone
If you sold $600+ on eBay, Etsy, or Venmo this year, the IRS now knows about it. Here's what you owe, what you can deduct, and how to avoid penalties.
Quarterly Taxes for Freelancers: Don't Wait Until April
If you owe $1,000+ at tax time and didn't make quarterly payments, the IRS adds a penalty. Here's when each payment is due and how to calculate the right amount.
LLC Formation: Which State Actually Saves You Money?
Wyoming sounds cheap until you see the registered agent fees. Here's the real 5-year cost comparison across all 50 states — formation, annual reports, and franchise tax.
Business & Legal
LLC, privacy, cookie consent, and payment processing
Cookie Consent in 2026: Google Now Requires Consent Mode v2
If you use Google Analytics or AdSense, you need Consent Mode v2 — or your data stops flowing. Here's how to add a compliant banner in under 5 minutes.
Privacy Policy Checklist: 9 Things Yours Is Probably Missing
GDPR fines hit 4% of global revenue. CCPA is $7,500 per violation. Most small sites are missing at least 3 required sections — here's exactly what to add.
Stripe vs PayPal vs Square: What You Actually Pay Per $1,000
They all say 2.9% + 30¢. But add in chargebacks, currency conversion, holds, and payout delays — and the real cost tells a different story.
Break-Even Analysis: The Number That Keeps Businesses Alive
Before you set your price, you need one number: how many sales to cover costs. Everything after that is profit. Here's how to find your break-even point.
Invoices That Actually Get Paid (On Time)
The #1 reason payments are late? Bad invoices. Missing details, unclear terms, and no payment link. Here's the anatomy of an invoice that gets paid fast.
Copyright & Public Domain: What You Can Actually Use for Free
That 1960 photo isn't necessarily public domain. Here's how to check — and the one rule change in 2023 that affected millions of works.
Side Hustle
Real profit after fees, taxes, and ad spend
Photo & ID
Passport, visa, and ID photo requirements
Image Tools
Formats, resizing, watermarks, and WebP conversion
PNG vs JPG vs WebP: Stop Using the Wrong Format
Using PNG for photos? Your pages are 3x heavier than they need to be. Using JPG for logos? Hello, compression artifacts. Here's the right format for every situation.
Watermarking Your Photos: What Actually Deters Theft
A tiny logo in the corner? That's cropped off in 2 seconds. Here's how to watermark so it protects your work without ruining the image.
Favicon in 2026: You Need More Sizes Than You Think
Just one favicon.ico? That was 2010. Now you need 16×16, 32×32, 48×48 for Windows, 180×180 for Apple Touch, 192 + 512 for Android. Here's the complete list.
Image Resizing: Why Your Photos Look Blurry on the Web
Uploading a 4000px photo to display at 800px? That's why your site is slow. Here's the right dimensions for every platform — web, social, print, email.
WebP: The Easiest 30% Speed Boost Your Site Can Get
Converting images to WebP makes your site 25-35% faster — same quality, smaller files. Both Lighthouse and Google PageSpeed literally tell you to do this. Here's how.
AI Tools
Background removal, upscaling, and AI writing
Creator & Video
YouTube SEO, captions, and QR codes
YouTube Titles: The 5 Things That Actually Affect Ranking
It's not just keywords. Title length, power words, year, emotional triggers, and (yes) clickbait avoidance all factor in. Here's the formula that works in 2026.
SRT Captions: Why 17 Characters Per Second Is Your Limit
If viewers can't read your captions before they disappear, they stop watching. Here's how to fix timing, convert between SRT and VTT, and handle the CPS limit.
QR Codes in 2026: Static vs Dynamic and Why It Matters
Static QR codes are forever — if the URL changes, you're reprinting everything. Dynamic codes let you change the destination. Here's when each one makes sense.
Developer Tools
JSON, JWT, regex, hashes, and other dev utilities
JSON Errors: The 5 That Waste 80% of Your Debug Time
Trailing commas. Missing quotes. Unescaped characters. These five JSON errors account for almost all parsing failures. Here's how to spot them fast.
JWT Tokens: The 3 Security Mistakes You're Probably Making
Accepting "alg: none," storing tokens in localStorage, not checking expiration — these three mistakes appear in roughly half of JWT implementations. Here's the fix for each.
MD5 Is Broken. SHA-1 Is Broken. Here's What to Use Instead.
If you're still using MD5 for anything security-related, stop. Collision attacks are practical and cheap. Here's when to use SHA-256 vs SHA-512, and why raw hashes are bad for passwords.
URL Encoding: The Bug That Happens When You Use the Wrong Function
encodeURI and encodeURIComponent produce different results. Pick the wrong one and your API calls silently fail. Here's the one rule that keeps you safe.
Regex Without the Headache: A Visual Cheat Sheet
Nobody memorizes regex. The trick is understanding 5 building blocks — character classes, quantifiers, groups, anchors, and flags — and combining them. Here's how.
Unix Timestamps: The #1 Bug Source in Every Codebase
JavaScript uses milliseconds. APIs use seconds. Mix them up and your dates show 1970. This one mismatch causes more bugs than any other datetime issue. Here's the fix.
UUID v4: 122 Bits of Randomness That Scale Globally
No central coordinator, no collision risk, works across every database and microservice. Here's why UUIDs are the default choice for distributed systems — and when they're not.
WCAG Contrast: That Light Gray Text Is Failing 15% of Users
One in seven people has some form of vision impairment. If your text-background contrast is below 4.5:1, they can't read it. Here's how to pick colors that work for everyone.
Passwords in 2026: "Correct Horse Battery Staple" Still Wins
Length beats complexity. "Tr0ub4dor&3" takes 3 days to crack. "correct horse battery staple" takes 550 years. Here's why passphrases changed the security game.
Base64: When to Use It (and When It Makes Things Worse)
Base64 increases file size by 33%. That's fine for embedding small images in CSS or API tokens, but terrible for large files. Here's the line where it stops making sense.
camelCase vs snake_case: Every Language's Convention in One Place
JavaScript: camelCase. Python: snake_case. CSS: kebab-case. SQL: SCREAMING_SNAKE. Don't mix them — here's the standard for every language you'll use.
Text & Data
Markdown, diff checking, and data format conversion
Markdown: Write Once, Publish Everywhere
READMEs, documentation, blog posts, Notion pages — Markdown is the format that works everywhere. Here's everything you need, from basic syntax to GFM tables and task lists.
Diff Checkers: Catch the One Word They Changed in Your Contract
They sent you a "minor revision" — but buried on page 4, the liability cap doubled. A diff checker finds every change in seconds. Here's how to use one effectively.
CSV ↔ JSON: The Conversion Pitfalls Nobody Warns You About
Commas inside values, newlines in fields, European semicolons, nested objects that don't flatten cleanly — here's what breaks when converting between the two most common data formats.
Want the tools behind the guides?
Every guide is powered by a free, privacy-first tool that runs entirely in your browser. No signup, no data collection.
Browse All 45+ Tools