Engineering notes.
War stories and design decisions from building an architecture editor whose diagrams run.
Federated query engines: one SQL query, four databases, zero ETL
How Trino-style engines join data across Postgres, MySQL, a data lake and a SaaS API without moving it first — pushdown, connectors, and the trade-offs.
Read the post →Hinted handoff: how a write succeeds while its replica is dead
The pattern that lets Cassandra and Dynamo-style stores keep accepting writes through node failures — and the read-consistency trap hiding inside it.
Merkle trees: how replicas find a needle of difference in a haystack of data
Why Cassandra, DynamoDB and git can compare gigabytes by exchanging kilobytes — the hash tree that powers anti-entropy repair, visually explained.
mTLS without secrets: workload identity with SPIRE
How SPIFFE/SPIRE gives every service a cryptographic identity — attestation, short-lived SVIDs, and mutual TLS where neither side holds a long-lived secret.
Raft, explained with one diagram: how clusters agree on anything
Leader election, log replication and the majority commit rule — the consensus algorithm behind etcd, Consul and CockroachDB, walked through visually.
Our simulation engine bans Date.now() and Math.random()
Total determinism is the load-bearing feature of techdiagrams.net — how a virtual clock and a seeded PRNG make every architecture failure replayable byte-for-byte.
Our AI copilot is two AIs — and one exists to argue with the other
Why the techdiagrams.net design copilot uses a designer model and a cross-vendor judge model, and why the AI is never allowed to touch your diagram directly.
The React bug that silently ate my users' text
Save on blur" is a contract with the DOM — and unmounting an input breaks it without telling you. A debugging story from building techdiagrams.net.
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