one concept at a time

technical notes

Practical notes on applied AI, HTTP caching, and reliable APIs, with interactive examples, runnable code, and primary references.

    • APIs
    • Idempotency

    Idempotency and duplicate requests

    How application programming interfaces (APIs) handle repeated requests with idempotency keys and a database uniqueness constraint.

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    • AI
    • Embeddings

    Text embeddings and cosine similarity

    An introduction to embeddings and cosine similarity, with a small vector sketch and a runnable example.

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    • HTTP
    • Caching

    HTTP caching and stale responses

    How fresh and stale responses work, with Cache-Control rules and a version check that can avoid a download.

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