Solution Architecture
Everything filed under Solution Architecture — essays, notes, playbooks and signals.
Essays5
Architecture Is a Story About Trust
Every boundary in a system is a statement about which team you trust to not break you.
Scale Is a Sequence, Not a Destination
Systems do not break at scale. They break in a predictable order, and knowing the order is most of the job.
The Agent-Shaped Codebase
Codebases are about to be read more often by agents than by people. That changes what "clean code" means.
The Review Is the Work
When generation is free, the scarce resource is judgement. That reframes what a senior engineer is for.
Watch read replicas stop helping
Replicas fix read saturation and nothing else. Here is the exact point where adding another one stops paying for itself.
Notes2
Playbooks4
Idempotency before retries
Adding retries to a non-idempotent endpoint converts a visible failure into an invisible one.
One writer per table
The cheapest way to keep a shared database from becoming a distributed monolith.
Outbox before dual writes
If a write has to land in two places, put it in one place and let a reader fan it out.
Read replicas before sharding
When read load is the bottleneck, the cheapest correct answer is almost never sharding.