System Design 101

What it is

System Design 101 is ByteByteGo’s set of visual guides that explain how software systems work in simple terms. The repository says it is for people preparing for a system design interview, and for anyone who wants to see how systems work beneath the surface. The README is a table of contents. Each category and each guide in it links to a page on bytebytego.com. The guides themselves sit in the repository as Markdown files under data/guides.

1. Open the README on GitHub
2. Pick a category from its table of contents
3. Follow a guide link to bytebytego.com
4. Read the guide: a diagram with text under it
5. Or clone the repository and search data/guides

Who it suits

Developers who want one picture and a few paragraphs on a topic such as caching, queues or logins. People preparing for a system design interview, which the README names as a use. Teachers who want a diagram to start a lesson from, within what the license allows (see Good to know).

Skip it if you want a course with exercises and an order to follow. The README lists the guides by category and gives no reading order.

Where to use it

The guides work anywhere you can open a web page or a Markdown file.

• GitHub: the README, which links every category and guide
• The guides website: bytebytego.com/guides, which GitHub lists as the repository’s homepage
• A local copy: clone the repository and search data/guides
• A coding agent: Claude Code, Codex, Cursor or another agent opened on the local copy

The README gives no steps for any coding agent. Mindket’s notes for Claude Code, Codex and Cursor are ordinary steps for giving an agent a folder to read, and they say so.

The README also links ByteByteGo’s YouTube channel and newsletter at the top. Mindket did not follow them.

How to set it up

Get it saves a zip of Mindket’s setup notes in your downloads folder. The guides need no install, and the README gives no install line.

1. Open the README on GitHub, or go to bytebytego.com/guides.
2. Pick a category and follow a guide link.
3. To keep a copy, clone the repository with the line below.
4. Open the folder in your editor or agent and look in data/guides.

git clone https://github.com/ByteByteGoHq/system-design-101.git

The clone line is ordinary Git on the address GitHub reports. It does not come from the maker’s README.

How to use it

Read one guide at a time. Each guide is a diagram with text under it, so look at the picture first and then read the text under it. On a local copy, a guide’s file name is the last part of its link in the README, so a title in the README leads you to its file.

With an agent, name the folder and the field you want searched, and ask it to give the file it used.

Search data/guides for guides about caching. List each title with its file name and what it covers, going by its description field.

A guide file holds the text and a link to its diagram, so the agent sees the words and not the picture. Open the guide on the website when the picture carries the point.

Example

Your system design interview is on Friday. You open the README, go to Technical Interviews and read How to Ace System Design Interviews. Its file gives a 7-step process:

1. Requirements Clarification
2. Capacity Estimation
3. Create High-Level Design
4. Database Design
5. Interface Design
6. Scalability and Performance
7. Reliability and Resiliency

You feel weakest on step 6. The README lists Top 5 Caching Strategies, Cache Eviction Policies and 8 Must-Know Scalability Strategies in its Caching & Performance and Cloud & Distributed Systems categories. You read those three, then close the page and explain each one aloud.

For newcomers and experts

If you are new. System design is the work of deciding how the parts of a software product fit together: the app, the servers, the database, a cache and the network between them. You do not need to know them all first. Each guide takes one idea and draws it. Start with How does gRPC work? or What Happens When You Type a URL Into Your Browser?, which follow a request step by step. A guide can be old, so look at the Updated date on its category page.

For experts. Each guide is a Markdown file with front matter. The five files Mindket read held a title, a description, an image, a createdAt date, a draft flag, a categories list and a tags list. A guide’s categories list holds the file name of its category, and scripts/readme.ts uses it to build the README’s table of contents, with guides sorted by createdAt. So a text search on a category’s file name, such as technical-interviews, lists its guides.

In the five guide files Mindket read, the diagram is not a file in the repository. Each image is an address on assets.bytebytego.com, so a local copy holds the words and a link for each picture. The script runs on tsx and gray-matter, and it rewrites README.md in place.

Good to know

The repository is Markdown text and links, the maker’s README script and a banner image (.github/banner.jpg). Nothing here runs on your computer unless you run the maker’s script.

• License: CC BY-NC-ND 4.0, from the README’s License section and LICENSE.md. GitHub lists it as Other, and package.json spells it cc-by-nc-sd-4.0, so go by the README. The guides, their diagrams and the website stay with ByteByteGo. The kit holds only Mindket’s own notes. It names guide titles and the seven step headings of one guide, and copies none of the guides’ body text or diagrams. Read the license before you share, print, teach from or change a guide
• Age: on 3 November 2026 GitHub’s answer showed the last push on 4 April 2025. The website may hold guides the repository does not, and Mindket did not compare them
• Reading order: none. The README is a table of contents, not a course
• Contributing: the maker’s file says "Please do not use AI tools to generate the content", and it sends diagram errors to a separate issue
• Outbound: reading loads GitHub or bytebytego.com. On 3 November 2026 the website’s pages loaded a Google Tag Manager script and a CookieYes consent script from cdn-cookieyes.com. They also loaded the diagrams from assets.bytebytego.com. The guide page Mindket saved embedded a newsletter frame from blog.bytebytego.com. That guide page, How does gRPC work?, showed its full text with no login
• Removal: delete the folder. Nothing else is installed unless you ran the maker’s script with its packages