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Content & Copywriting
Turning words on a page into signups and sales.
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Learn & Grow Your Business
19 interactive guides across 6 tracks — marketing, content, DSA patterns, system design, and finance. Pick a track and start reading.
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Every guide belongs to one of these tracks. Jump straight to the one you need.
7 guides
Marketing & Growth
Channels, traffic, and the numbers that tell you it is working.
Positioning
The Horsepower Rule
Watt sold steam engines in horses, not watts. A live translator, a price-anchor calculator, a jargon test, and 18 worked before/after examples.
Read more Acquisition
Competitor Marketing
How to reach the customers of a bigger rival — ten tactics, how close to stay to their brand, what their bad reviews tell you, and what not to do.
Read more SEO
The SEO Heist Strategy
The six-step method for turning a competitor's sitemap into a few thousand AI-written articles, and the traffic case behind it.
Read more SEO
SEO Roadmap
What to learn first if you're new to SEO, in order, plus six free places to learn each part.
Read more Business
Client Acquisition Channels
A filterable list of ways to find clients, sorted by type, the work each takes, and what it costs.
Read more Marketing
$0 Marketing Strategies
Seven tactics you can run this week without ad spend, from Hacker News comments to Giphy to comparison-site listings.
Read more Business
Startup Metrics That Matter
MRR, CAC, LTV, churn, burn and the rest, in plain terms, with when each one is the number to watch.
Read more6 guides
DSA Patterns
Interview algorithm patterns with animated stories, visualizers, and TypeScript.
DSA
Two Pointers Pattern
The pair-sum and palindrome trick, walked through with a visualizer, TypeScript, and LeetCode problems to try.
Read more DSA
Sliding Window Pattern
How to turn a nested-loop subarray problem into one pass, with an array visualizer and practice problems.
Read more DSA
Fast and Slow Pointers
Floyd's cycle detection: why a fast and a slow pointer always meet inside a loop, with a linked-list visualizer.
Read more DSA
In-Place Linked List Reversal
Flip every pointer in a linked list with the prev/curr/temp technique. One pass, no extra space.
Read more DSA
Binary Search Pattern
Throw away half the candidates with every comparison. Find a value, a boundary, or the answer to a monotonic question.
Read more DSA
Top K Elements Pattern
Why a size-k min-heap beats sorting the whole array when you only need the top few, shown with a heap visualizer.
Read morePlus 10 attempt-by-attempt LeetCode case studies on the DSA hub. See them all →
3 guides
System Design
The systems behind working software, drawn out and clickable.
System Design
The API Lifecycle
The eight stages every API moves through, as a loop you can click through, plus a self-audit that names your weakest stage.
Read more System Design
INNER JOIN vs OUTER JOIN
Two small tables, one shared key. Toggle INNER, LEFT, RIGHT and FULL and watch the result set change row by row, plus a self-check quiz.
Read more System Design
How to Choose a Database
Seven laws that start from your queries instead of the vendor feature list, as a clickable chain, plus five scaling lenses and a self-check quiz.
Read more1 guide
Finance
The valuation maths behind the headlines, made interactive.
1 guide
GTM & Sales Automation
The tools GTM engineers actually argue about, compared and made interactive.
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