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Al Beltran

Software engineer

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Engineering Journal

Notes on systems that have to work in production

A reviewable knowledge base beside the portfolio. Published notes only. Interview prep lives in the Interview Lab. Planned titles stay in the topic map until they are written.

  8. Stacked dark server plates and a single blue data ribbon in a magazine still life
    Architecture

    When the GPU Vendor Owns the Model Hub

    If the company that sells the chips also owns the default place engineers pull open models, pinning, licensing, and exit plans stop being theoretical.

    #ai#open-source#infrastructure#vendors
  10. A single compact storage module glowing on a dark metal bench
    Architecture

    SQLite Is Back, and the Edge Is Why

    D1, Turso, LiteFS, and a decade of Postgres-by-default have teams rediscovering a file database. The win is locality. The bill is replication and migration discipline.

    #sqlite#edge#databases#architecture
  11. Scattered paper indices and a focused blue reading lamp over a dark desk
    Workflow

    Why Most RAG Demos Die in Production

    Retrieval-augmented generation looks finished in a notebook. In production it is a search problem, a freshness problem, and an evaluation problem wearing a chat UI.

    #ai#rag#search#evaluation
  12. Two identical brass keys on a dark slate, one catching a thin blue highlight
    Architecture

    Idempotency Keys Are the Real API Contract

    Retries are not an edge case. If a client can double-submit a payment, a reward, or a provision call, the header that names the attempt is the interface.

    #apis#idempotency#reliability#fintech
  13. Layered glass plates with a faint lattice, lit by a cold blue edge
    Security

    Post-Quantum TLS Is an Operations Problem

    Hybrid key exchange is landing in browsers and CDNs. The engineering work is inventory, dual-stack certificates, and not breaking the middleboxes you forgot you had.

    #security#tls#cryptography#operations
  14. A dark workshop bench with aligned metal tools and a single blue work light
    Workflow

    Platform Engineering Is Not a Portal

    A golden path is paved workflows, paved defaults, and a team that owns the pavement. A catalog of links with a search bar is a bookmark manager.

    #platform#devops#developer-experience#delivery
  15. A stopwatch and a thin server blade on black, with a blue second-hand highlight
    Cloud

    Serverless Still Has a Latency Budget

    Managed functions removed capacity planning. They did not remove tail latency, cold starts, or the cost of chatty downstreams. You still have a budget. It is just itemized differently.

    #serverless#aws#lambda#performance
  17. Interlocking dark geometric blocks forming a bridge, with a blue connecting pin
    Engineering

    TypeScript Won the Integration Layer

    The interesting TypeScript story is not frontend fashion. It is the language teams use to glue APIs, workers, and infrastructure code that used to be a pile of untyped scripts.

    #typescript#node.js#architecture#tooling
  18. Overlapping translucent frames on a dark table forming a precise grid
    Frontend

    CSS Finally Caught Up to the Layout We Hacked

    Container queries, :has(), and nested CSS removed a generation of JavaScript measuring hacks. The remaining work is restraint: not every layout needs a new primitive.

    #css#frontend#design-systems#web
  19. A dark rail switch with one track lit blue and the other in shadow
    Workflow

    Feature Flags Beat Long-Lived Branches

    A flag in production is a smaller, reversible risk than a branch that only exists on one laptop. Trunk-based delivery is an operations choice, not a Git fashion.

    #feature-flags#delivery#git#release
  20. A sealed crate on a dark loading dock with a broken seal catching blue light
    Security

    Supply Chain Security Is a Runtime Problem Now

    xz and a decade of npm incidents taught the same lesson: you run other people's code. Pinning, provenance, and a small dependency graph beat a PDF named policy.

    #security#supply-chain#npm#operations
  21. A split dark interior: empty storefront glass on one side, a lit workshop on the other
    Frontend

    The SPA Hangover and What Server Components Are For

    Client-rendered apps solved a 2015 shipping problem. They also shipped empty shells and waterfalls. Server Components are a boundary tool, not a rewrite religion.

    #react#rsc#next.js#frontend
  22. Two notebooks overlapping on a dark desk, one page catching a blue edge light
    Architecture

    Local-First Sync Is a Product Problem

    CRDTs and sync engines are impressive. Users still need a story for conflict, offline writes, and what happens when two cashiers sell the last seat.

    #local-first#sync#offline#product
  23. A dark ledger book open under a precise blue desk lamp
    Engineering

    SQL Is Still the Skill That Compounds

    Models can draft a query. They cannot own the index, the cardinality, or the 2 a.m. plan that scans the wrong partition. Relational literacy is still leverage.

    #sql#databases#performance#engineering
  24. A narrow dark corridor with a measured blue light bar like a capacity gauge
    Architecture

    Rate Limits Are Product Design

    429s are not just a WAF rule. They encode who gets capacity, what a client should do next, and whether your API is a partner or a trap.

    #apis#rate-limiting#product#reliability
  25. A sealed glass capsule on a dark bench with circuitry faintly visible inside
    Engineering

    Wasm on the Server Is a Boundary Tool

    WebAssembly in the data center is useful when you need isolation, multi-language plugins, or a portable sandbox. It is not a replacement for a well-run service.

    #wasm#architecture#isolation#platforms
  27. A long dark film strip of sequential frames with one frame lit blue
    Architecture

    Event Sourcing Without the Religion

    An event log is a tool for audit and replay. It is not a requirement for every domain object. Most systems need durable facts and a projection, not a conference architecture.

    #event-sourcing#architecture#audit#messaging
  28. A dark glass pane with a faint volumetric light field behind it, studio still life
    Frontend

    WebGPU Makes the Browser a Compute Node

    When the tab can run serious GPU work, the architecture question is not 'can we?' It is 'should this run next to the user's passwords, and what is the fallback?'

    #webgpu#graphics#performance#web
  32. Cascading dark metal trays like a data pipeline
    Cloud

    Lessons from Serverless ETL on AWS

    What matters when Lambda, S3, and Step Functions process high-volume data under production SLAs.

    #aws#serverless#etl#step-functions#lambda