System Design Knowledge Base
Architecture
A knowledge base of system design and architecture: distributed systems, data infrastructure, workflow engines, and AI infrastructure.
Distributed Systems
5 Mar 2026
Durable Workflow Engines: A Queue Is Not the Source of Truth
Follow one five-day automation to see what queues, idempotency, and durable workflow engines each solve when processes crash.
21 Apr 2026
Building a Durable Workflow Engine
Build durable execution around Postgres and a queue, including unique starts, outbox delivery, fenced work, timers, signals, and safe side effects.
12 May 2026
Durable Workflows with Temporal
Follow the same multi-day automation on Temporal to learn replay, activities, sagas, versioning, and the guarantees applications still own.
AI Infrastructure
3 Sept 2026
Designing an AI Gateway
Follow one model request through identity, policy, routing, failover, streaming, cost accounting, caching, and observability.
20 Aug 2026
Semantic Caching for LLM Calls
Learn when a semantic cache can safely reuse an LLM answer, how false hits happen, and how tenant boundaries, evaluation, and freshness limit the risk.
Integrations
18 Jun 2026
Receiving and Sending Webhooks Reliably
Follow webhooks in both directions, from signature verification and deduplication to durable sending, retries, endpoint isolation, and delivery logs.
13 Jan 2026
Keeping Multi-Tenant OAuth Connections Healthy
Follow one customer connection through OAuth consent, encrypted storage, refresh races, provider failures, quarantine, and reconnection.