Under the Hood

The Curriculum

Seven tracks, from fetch() down to packets and pages, through to distributed systems and interview craft.

Two deep tracks — networking and databases — go all the way down to packets and pages. The other five stages build back up: the building blocks, the consistency trade-offs, the APIs, the distributed patterns, and the worked case studies an interview actually asks for.

  1. Track NDeep track

    Networking, under the hood

    The full life of a request: from fetch() in your code down to packets, and back.

    10 lessons

  2. Track DDeep track

    Databases, under the hood

    How Postgres actually executes your query: pages, B-trees, WAL, MVCC.

    5 lessons

  3. Stage 1

    Core building blocks

    Load balancers, caches, CDNs, object storage, queues, rate limiting.

    Coming in phase 2/3

  4. Stage 2

    Data & consistency at scale

    Replication, CAP/PACELC, consistency models, quorums, conflicts.

    Coming in phase 2/3

  5. Stage 3

    Communication & APIs

    REST vs gRPC vs WebSockets, idempotency, pagination, versioning, backpressure.

    Coming in phase 2/3

  6. Stage 4

    Distributed patterns

    Event-driven systems, outbox, sagas, consensus, the exactly-once myth.

    Coming in phase 2/3

  7. Stage 5

    Case studies & interview craft

    Worked designs — chat, feed, dispatch, ledger — with the interview framework.

    Coming in phase 2/3