Artículos

WebSocket production patterns: heartbeats, backpressure, and graceful shutdown in Node.js

Ship bidirectional real-time APIs that survive proxies, load balancers, and traffic spikes. Heartbeats, ping/pong, write buffering, auth at upgrade time, and Kubernetes-friendly shutdown.

JSON Schema validation for LLM tool calls: contracts, AJV, and fail-closed execution in TypeScript

Validate LLM tool arguments as untrusted input: JSON Schema design, AJV compilation, strict object rules, and a typed dispatcher pattern for production TypeScript backends.

Load shedding for HTTP APIs: prioritization, degradation tiers, and backpressure

Autoscaling lags behind spikes. Load shedding rejects low-priority work so critical APIs stay fast: signals, priority buckets, Node admission sketches, HTTP semantics, and pitfalls.

Request coalescing and single-flight: stopping cache stampedes before they flatten your database

Why synchronized TTL expiry causes thundering herds, how in-process and distributed single-flight deduplicate work, and trade-offs when scaling Node.js and Redis-backed caches.

OpenAPI as the source of truth: codegen, drift detection, and breaking-change gates

Using OpenAPI as an executable contract—typed clients, server validation, CI diff gates, and workflows that keep specs and implementations aligned in production API teams.

GitHub Actions OIDC with AWS: short-lived CI credentials without static access keys

Replace static AWS keys in CI with OIDC to IAM roles: GitHub issuer registration, trust policies on jwt claims, least-privilege roles, and common integration failures.

Distributed scheduled jobs: leases, idempotency, and why clocks lie

Run cron-like work safely across replicas: leader leases, idempotent handlers, scheduling semantics with skew, and operational patterns for Node.js and Postgres-backed workers.

HTTP API admission control: concurrency limits, queues, and load shedding

Cap concurrent HTTP handlers per instance, add bounded queue waits or fail fast with 503s, and align limits with database pools and Kubernetes readiness. Focused on Node.js production APIs.

Presigned URL uploads to object storage: security boundaries, pipelines, and async verification

Ship browser-to-bucket uploads without proxying bytes through your API. Policy fields, content-type constraints, key layout, malware scanning hooks, and the failure modes teams hit in production.

API contract testing with Pact: consumer-driven workflows for polyglot services

Pact contract tests for HTTP APIs: consumer expectations, provider verification with states, broker workflows, and where they complement—not replace—integration tests.

Node.js AsyncLocalStorage: request-scoped context without globals

Carry correlation IDs, auth, and tenancy through async call chains in Node.js using AsyncLocalStorage. CLS patterns, pitfalls with worker threads, and testing strategies for production APIs.

RFC 9457 Problem Details for HTTP APIs: stable errors clients can rely on

Use application/problem+json to return structured API errors with types, titles, and extension fields. Mapping exceptions, validation, and proxy behavior for production HTTP services.

PostgreSQL LISTEN/NOTIFY: real-time invalidation, delivery semantics, and when to stop

Use LISTEN/NOTIFY for lightweight pub/sub from Postgres to app servers: payload limits, no persistence, connection pooling pitfalls, and patterns that stay correct under load.

JWT vs opaque API tokens: sessions, revocation, and scalability trade-offs

Compare signed JWTs with opaque server-side tokens for APIs: verification cost, revocation semantics, storage, and patterns that hold up under mobile, B2B, and high-QPS backends.

PostgreSQL advisory locks: coordination without touching rows

When and how to use session and transaction advisory locks in Postgres for jobs, migrations, and cross-request serialization, with pooling caveats and a Node.js example.

LLM-as-judge evaluation: rubrics, calibration, and production pitfalls

Using models to score or rank other model outputs: rubric design, calibration against humans, bias risks, and how to combine automated judges with spot checks in shipping AI features.

PostgreSQL connection pooling in Kubernetes: sizing pools, PgBouncer, and Node.js pitfalls

Right-size Node.js DB pools behind replicas so you do not exhaust PostgreSQL max_connections. PgBouncer modes, prepared statements, checkout timeouts, and what to measure in production.

Hybrid logical clocks: ordering events when wall clocks lie

Use HLCs to assign monotonic, causally aware timestamps across nodes without tight clock sync. How they work, comparison to Lamport clocks, and production patterns for logs and APIs.

OAuth 2.1 for production APIs: authorization code, PKCE, refresh rotation, and M2M boundaries

Ship browser and mobile clients without long-lived secrets in the bundle. How OAuth 2.1 tightens the authorization code flow, why refresh rotation matters, and when client credentials fit.

Request deadlines, cancellation, and backpressure in Node.js HTTP services

Propagate timeouts with AbortSignal, stop wasted work when clients disconnect, and align server deadlines with upstream calls. Patterns for fetch, pools, and long handlers in production APIs.

Optimistic concurrency for HTTP APIs: ETags, If-Match, and conflict design

Prevent lost updates without pessimistic locks: versioned resources, conditional requests, 412 vs 409, and how optimistic concurrency interacts with caching, BFFs, and mobile retries.

HTTP streaming in production backends: SSE, chunked transfer, proxies, and backpressure

Designing long-lived HTTP responses for live dashboards and LLM-style token delivery: Server-Sent Events vs chunked bodies, intermediary buffering, timeouts, and safe client reconnection.

Service level objectives and error budgets: turning reliability into a product decision

How SLIs, SLOs, and error budgets connect user-visible reliability to engineering trade-offs: choosing indicators, setting targets, and using burn alerts without drowning in metrics.

Multi-turn LLM backends: session state, retrieval, and tool-call loops without losing the thread

Session-backed LLM APIs: durable turns, bounded context, RAG outside the transcript, tool-call round-trips, and per-session isolation—patterns from production assistants.

Distributed locks and fencing tokens: why TTL alone is not enough

Lease-based locks in Redis or etcd prevent most double execution—but a delayed process can still corrupt shared state. Fencing tokens from a linearizable store close the gap. Patterns, SQL integration, and pitfalls.

Server-side feature flags in distributed backends: evaluation, consistency, and kill switches

How to use feature flags beyond the frontend: where to evaluate rules, how to keep behavior consistent across services, and operational patterns for safe rollouts and instant rollback.

Dead-letter queues for async backends: when to use them, how to design them, and how not to drown in poison messages

Turn poison messages and partial failures into safe replays: DLQ naming, redrive policies, idempotency, observability, and cases where a DLQ is the wrong abstraction.

Read-your-writes consistency: when CDNs and caches lie (and how to fix it)

Users refresh and still see stale data after a successful write. This article explains read-your-writes consistency, cache-control patterns, surrogate keys, and tokenized URLs for edge-cached APIs.

PostgreSQL Row-Level Security: tenant isolation that survives application bugs

How PostgreSQL RLS enforces tenant isolation in the database: session variables, policy patterns, indexing trade-offs, and pitfalls in multi-tenant SaaS.

Read-your-writes consistency: replicas, routing, and session tokens

After a write, users expect to see their change immediately. Async replication breaks that illusion—here is how sticky routing, monotonic tokens, and cache discipline restore read-your-writes without giving up scale.

LLM trust boundaries: prompt injection, tool abuse, and defense in depth

Treat LLM inputs as untrusted code: separate system from user content, constrain tools, validate outputs, and layer controls so assistants cannot exfiltrate secrets or hijack workflows.

Zero-downtime database migrations: the expand-contract pattern in practice

Ship relational schema changes without maintenance windows using expand-contract phases, backfills, and safe cutovers—patterns that keep production APIs available under load.

Graceful shutdown for HTTP services: signals, draining, and Kubernetes

Stop Node and containerized APIs without 502 spikes: SIGTERM semantics, draining in-flight requests, readiness vs liveness, and background job coordination.

Semantic caching for LLM APIs: cost, latency, and correctness

Reuse model outputs when prompts are paraphrases, not byte-identical strings. Embedding-based cache keys, TTLs, invalidation, and guardrails for production LLM backends.

Keyset pagination: building stable, scalable list APIs

Why OFFSET-based pagination breaks at scale and how cursor (keyset) pagination uses indexed columns for predictable latency, with SQL patterns and API design.

Optimistic UI with server reconciliation: patterns that survive production

How to ship instant-feeling interfaces without lying to users: mutation lifecycles, rollback rules, idempotency, and conflict handling when the server is the source of truth.

Production webhook receivers: signatures, replay protection, and idempotent delivery

How to build webhook HTTP endpoints that survive retries, clock skew, and malicious traffic: HMAC verification, timestamp windows, deduplication, and clear response contracts.

Distributed sagas: choreography vs orchestration in production systems

Compare event-driven choreography and orchestrator-led sagas for multi-step workflows: coordination models, failure handling, observability, and when to choose each.

Production LLM API integration: streaming, structured outputs, and resilience

How to ship LLM features behind your API: SSE streaming, JSON schema contracts, retries, timeouts, and cost controls—without turning your backend into an unreliable demo.

RAG pipelines in production: chunking, retrieval, and evaluation

How to design retrieval-augmented generation for real systems: text splitting, embedding strategy, reranking, guardrails, and how to measure quality before users do.

Distributed tracing with W3C Trace Context and OpenTelemetry

How W3C trace context and OpenTelemetry connect spans across services: propagation, span design, sampling strategies, and production pitfalls for backend systems.

API rate limiting: token buckets, sliding windows, and distributed fairness

How to choose algorithms for HTTP APIs, implement limits that survive restarts and multiple nodes, and communicate limits clearly to clients—without turning throttling into guesswork.

The transactional outbox: publishing events without losing data or doubling work

Why dual writes fail between databases and message brokers, how the outbox pattern fixes it with atomic commits, and how to run workers, polling, and trade-offs in production.

API evolution and backward compatibility

A structured look at versioning strategies, deprecation, and communication patterns that keep integrations stable while software continues to change.

Operational observability for production services

How structured signals—logs, metrics, and traces—support incident response and steady improvement without overwhelming engineering teams.

Circuit breakers, bulkheads, and timeouts: isolating failure in distributed systems

How to combine circuit breakers, resource isolation, and explicit timeouts so one slow dependency does not take down your API—patterns, trade-offs, and Node.js-oriented examples.

Idempotency keys: designing safe retries for HTTP APIs

How idempotency keys let clients retry network failures without duplicate side effects, with storage patterns, HTTP semantics, and production pitfalls.

Governing AI-assisted software development

How large language models shift cost from authoring to verification, and which governance patterns preserve review quality, security, and clear ownership in engineering teams.

TypeScript discipline at scale

Why gradual typing pays off for teams shipping production web software, and how conventions keep complexity manageable.