Search

Lessons (33)

• Timeouts, Retries & Backpressure

  A slow dependency should consume a bounded budget, not create an infinite retry storm. The big idea A …

• Resilience Patterns

  … wait time before each retry" x-axis ["retry 1", "retry 2", "retry 3", "retry 4", "retry 5"] y …

• Exactly-Once Payment Processing

  Safe payment retries need a durable idempotency record, atomic state transition and provider-side deduplication. The invariant For …

• Kafka Producers

  … batching, compression, partitioning, the acks setting that trades speed for safety, retries, and the idempotent producer. The big …

• Design a Reliable Notification System

  … Watch oldest-job age, provider errors, retry rate, opt-out enforcement and tenant backlog.

• Consumers & Consumer Groups

  … retries and dead-letter topics What if a message can't be processed (bad data, a downstream API …

• Message Queues & RabbitMQ

  … Learn producers, consumers, acknowledgements, exchanges, retries and dead-letter queues with RabbitMQ. The big idea At a busy …

• The L6 System-Design Thinking Loop

  … Walk one crash, timeout, or retry. 5. Explain metrics, mitigation, and the durable fix. 💡 A good trade-off …

• REST API Design

  … Idempotency for unsafe retries ⭐ Networks fail. A client sends POST /payments , the connection drops, and the client doesn …

• Creational Patterns: How to Make Objects

  … 10 000, retries: 0 }; url(url) { this. config.url = url; return this; } method(method) { this. config.method = method …

• Delivery Guarantees: At-Most, At-Least & Exactly Once

  … producer ID + sequence numbers let the broker drop retried duplicates. It's on by default in modern Kafka …

• API Gateway, BFF & Service Discovery

  … networking as infrastructure As services multiply, every one needs retries, timeouts, mutual TLS, metrics and tracing. Instead of …

• Scaling, Load Balancing & Rate Limiting

  … Over the limit → 429 Too Many Requests with a Retry-After header. Token bucket (most popular) 🪣 A …

• Meaningful Names

  … users , orderItems userList2 , arr Constant UPPER SNAKE MAX RETRIES , TAX RATE n , x mermaid flowchart LR Q{What …

• Database Indexing & Transactions

  … 3; -- 0 rows → someone else won, reload and retry Pessimistic ( FOR UPDATE ) Optimistic ( version ) --- --- --- Idea "Lock it, then …

• Design a Chat Application

  … A client idempotency key makes reconnect/retry safe. Order messages by conversation key, not globally. Presence is temporary …

• Design a Ride-Sharing Service

  … Match nearby candidates, then atomically lease one driver; release/retry on rejection or timeout. Locations are eventually consistent …

• Real-Time, Pub/Sub, Webhooks and CDC

  … with event ID Webhook Notify another server Sign, retry and make receiver idempotent WebRTC Direct low-latency media …

• Debug Latency Like an Investigator

  … Only p99 rises Queueing, locks, GC, pool wait, retries, slow subset. Every morning Batch reports, backup, cache expiry …

• Transactions, Indexes & Concurrency

  … Livelock means actors keep retrying/changing but make no useful progress. Use consistent lock order, short transactions and …

• Comments & Formatting

  … const PAYMENT MAX RETRIES = 3; That second comment is gold: no amount of good naming could tell you …

• ACID, Transactions & Locks

  … wait in a cycle; databases normally abort one. Retry only the aborted transaction with bounded backoff and idempotency …

• Serverless Architecture

  … Event sources retry; the same event may arrive twice Push work to queues Smooth spikes, retry failures, add …

• Which Pattern Do I Need?

  … wrapping 3rd-party libraries 3. ☕ Decorator — middleware, HOCs, retry/cache/log wrappers 4. 🏨 Facade — service layers and SDKs …

• Small Functions That Do One Thing

  … false, retries: 3 }); ⚠️ Boolean flag arguments are a smell. render(true) usually means the function does two things …

• Clean Error Handling

  … error where you can do something about it : retry, use a fallback, or show a message. Everywhere else …

• Monolith vs Microservices

  … call that becomes a network call needs timeouts, retries, idempotency, authentication, monitoring and versioning. The middle path: the …

• Deployments, ReplicaSets & Rollouts

  … migrations, batch processing Retries until it succeeds CronJob Scheduled jobs: nightly reports, cleanups Creates Jobs on a cron …

• State Management (Redux, Zustand, TanStack Query)

  … loading and error states, caching, background refetching, deduplication, retries and invalidation after mutations. Don't hand-roll that …

• Service Communication: Sync vs Async

  … timeout = one slow service can exhaust every thread. - 🔁 Retry with backoff , but only idempotent operations. - ⚡ Circuit breakers to …

• Deploying & Operating Microservices

  … have: - [ ] Health endpoints ( /health/live , /health/ready ) - [ ] Timeouts, retries with backoff, and circuit breakers on outgoing calls - [ ] Graceful …

• Observability: Logs, Metrics & Traces

  … events (order placed) ✅ warn Something odd but handled (retrying) ✅ error A request failed ✅ + alert on spikes fatal The …

• React Hooks in Practice

  … They handle caching, deduplication, retries and race conditions for you. You might not need an effect Effects are …