How Things Work

Everything has a mechanism.

Explore what happens beneath the interfaces, APIs and systems we use every day. No walls of documentation. Just ideas brought to life.

ReadySend a request and watch the path it takes.

Try this

Same request, different path. Click any component to see what it does.

Each request, to scale

No requests yet. Each one is drawn here to scale.

networkRedisPostgrestimeout
Sheet 00 · A request, end to endA running simulation, not a recordingTimings illustrative
The plates

Pick a system and take it apart

Nº 01Memory and Data

Redis

What happens when an application remembers something?

Interactive6 min
Nº 02Distributed Systems

Apache Kafka

How does data move between independent systems?

Interactive8 min
Nº 03Artificial Intelligence

LLMs

How does a model generate its next token?

On the drawing board≈ 7 min
Nº 04Containers and Infrastructure

Docker

What actually happens when you run a container?

On the drawing board≈ 6 min
Nº 05Containers and Infrastructure

Kubernetes

Who keeps your applications running when things fail?

On the drawing board≈ 9 min
Nº 06Artificial Intelligence

AI agents

What happens when an AI can choose tools and take actions?

On the drawing board≈ 7 min
Nº 07Artificial Intelligence

RAG

How can an AI answer questions using external knowledge?

On the drawing board≈ 6 min
Nº 08Memory and Data

Databases

What really happens when you execute a query?

On the drawing board≈ 8 min
Nº 09The Request Journey

Nginx

How does one server handle thousands of connections?

On the drawing board≈ 5 min
Nº 10Shipping Software

CI/CD

How does code travel from a developer's laptop to production?

On the drawing board≈ 5 min
Nº 11Shipping Software

GitHub Actions

What happens after you push a commit?

On the drawing board≈ 5 min
Collections

How the pieces connect

01The Request JourneyFrom a typed address to a response.6 concepts
DNSHTTPReverse proxiesNginxLoad balancingAPIs
02Memory and DataWhere state lives, and how it stays true.6 concepts
RedisPostgreSQLDatabase indexesTransactionsConnection poolingDatabase replication
03Distributed SystemsAgreement between machines that can't see each other.6 concepts
Apache KafkaMessage queuesEvent-driven architectureConcurrencyDistributed locksConsensus
04Containers and InfrastructureWhat actually runs, and what restarts it.6 concepts
DockerKubernetesContainer networkingService discoveryScalingHealth checks
05Shipping SoftwareThe road from a commit to production.6 concepts
GitGitHub ActionsCI/CDBuild pipelinesDeployment strategiesRollbacks
06Artificial IntelligenceModels, retrieval, and systems that take actions.10 concepts
How LLMs workTokenisationEmbeddingsVector searchRAGAI agentsTool callingMCPAgent memoryMulti-agent systems
07The WebThe layers under every page load.6 concepts
BrowsersDNS resolutionTCP and TLSHTTP requestsWeb serversWebSockets