Open Source & Free Forever

The system design
workbench you
actually need

Static primers get you started. ArchForge gets you hired and keeps you sharp. 60+ interactive patterns, a real-time capacity planner, AI/LLM architecture blueprints, and architecture templates you can use in your next interview or production system.

Explore Patterns Capacity Calculator
60+
DESIGN PATTERNS
8
CATEGORIES
7
AI/LLM PATTERNS
6
INTERVIEW TEMPLATES
100%
FREE & OPEN SOURCE

Built for how engineers
actually learn systems

The system design primer is great reading. ArchForge is where you come when you need to think, practice, and design for real.

📋

60+ Interactive Pattern Cards

Every pattern includes when to use it, what you give up, complexity rating, and which patterns it pairs with. Not just a definition but a decision framework.

PATTERN LIBRARY
📈

Real-Time Capacity Calculator

Slide your DAU, requests, and data shape. Get instant estimates for RPS, peak load, storage growth, bandwidth, and cache size. No more back-of-napkin guessing.

CAPACITY PLANNING
🤖

AI and LLM Architecture Patterns

RAG pipelines, vector database integration, LLM serving at scale, multi-agent orchestration. Patterns that did not exist when the primer was written.

AI / ML SYSTEMS
🛠

Copy-Ready Architecture Templates

Six fully worked system designs from URL shorteners to ride-sharing apps. Each one includes component list, data models, scale targets, and known trade-offs.

INTERVIEW READY

Cloud-Native and Edge Patterns

Kubernetes operators, serverless functions, edge computing, service meshes. The patterns production teams actually argue about in architecture reviews.

MODERN STACK
⚖️

Head-to-Head Comparison Tables

SQL vs NoSQL, REST vs gRPC vs GraphQL, Redis vs Memcached. Visual matrices with quantified trade-offs so you can argue a choice, not just state one.

COMPARISON MODE

60+ patterns, organized
by what you need to decide

Filter by category or search by name. Click any card for full details including trade-offs, when to use it, and related patterns.

Estimate any system
before you design it

Adjust the sliders to match your system profile. The numbers update live so you can see how a 10x growth in users changes your infrastructure requirements.

Peak multiplier is set to 3x average. Assumes 10% hot data for cache sizing and 100 ms average query time for DB connections. Adjust for your system.
Average RPS
5,787
requests / second
Peak RPS
17,361
3x average burst
Daily Storage
19.1 GB
new data per day
Total Storage
34.9 TB
over 5 years
Peak Bandwidth
165.5 MB/s
at peak RPS
Cache Size
3.5 TB
10% hot data

Walk into your next design
interview with a plan

Six fully worked system designs with component breakdowns, data models, scale targets, and the specific trade-offs you should mention out loud.

Patterns that did not exist
in 2020 but define 2026

ArchForge is the only free, open-source reference that covers production AI infrastructure patterns at the same depth as classic distributed systems patterns.

See how ArchForge compares
to what you know

This is not a knock on other resources. Each one serves a purpose. This table shows you where ArchForge fills the gaps.

Feature ArchForge System Design Primer ByteByteGo Grokking
AI / LLM Architecture Patterns 7 patterns None Partial None
Interactive Capacity Calculator Built-in Static tables
Total Patterns Covered 60+ ~20 Many ~15
Edge / Serverless Patterns Partial
Vector Database Pattern Partial
Architecture Templates 6 detailed 8 solutions
Completely Free Freemium Paid
Open Source