Bandwidth
The maximum amount of data that can be transferred over a network in a given time. It's the width of the pipe, not how fast the water flows.
What is Bandwidth?
The maximum amount of data that can be transferred over a network in a given time. It's the width of the pipe, not how fast the water flows.
Bandwidth is a foundational concept that sits in the Core Fundamentals area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Bandwidth" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
Learn Bandwidth in depth
Full interactive lesson with diagrams, code examples, real-world references, and a quiz.
Open the Bandwidth lessonRelated lessons
Lessons that touch on Bandwidth as part of a larger topic.
Data Compression
Reduce data size to save storage and bandwidth, lossless vs lossy, and when each makes sense
advanced · consistency models
Network Optimization
Reduce latency and bandwidth usage, compression, connection pooling, and protocol tuning
advanced · reliability resilience
Network Monitoring
Watching the wires, bandwidth, latency, packet loss, and connectivity between your services
intermediate · observability monitoring
See also
Related glossary terms you might want to look up next.
Latency
The time delay between sending a request and getting a response. Amazon found every 100ms of extra latency costs 1% in sales.
Throughput
The number of operations a system can handle per unit of time. Think of it as how many cars a highway can move per hour.
CDN
A network of servers distributed globally that caches content close to users. Netflix uses CDNs to stream video from servers near you, not from one central location.