Notes and developer tools on backend, system design, PostgreSQL, Redis, Laravel and AI-assisted engineering.https://sade.dev/en-UShttps://sade.dev/en/notes/serverless-migration-decision/https://sade.dev/en/notes/serverless-migration-decision/Before you move to FaaS: the real cost of cold-start latency, vendor lock-in risk, and the workloads where serverless actually pays offSat, 11 Jul 2026 00:00:00 GMTserverlessarchitecturecloudNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/bff-backend-for-frontend/https://sade.dev/en/notes/bff-backend-for-frontend/Separate API layers for mobile and web: the hidden cost of bending one API to fit every client, and when a BFF is actually warrantedSat, 04 Jul 2026 00:00:00 GMTarchitectureapibffNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/sync-vs-async/https://sade.dev/en/notes/sync-vs-async/Should a job run inside the HTTP request or go to a queue? The decision line, drawn through response time, fault tolerance, and consistencySat, 27 Jun 2026 00:00:00 GMTarchitecturequeueasyncapiNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/systems/transactional-outbox-dual-write-and-idempotent-consumption/https://sade.dev/en/systems/transactional-outbox-dual-write-and-idempotent-consumption/Writing to the database but failing to put the event on the queue: closing dual-write with an outbox, suppressing the at-least-once repeats it creates, and encrypting the field.Mon, 22 Jun 2026 00:00:00 GMTarchitecturemessagingidempotencyreliabilitysecuritySysteminfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/when-event-driven-architecture/https://sade.dev/en/notes/when-event-driven-architecture/The price of loose coupling through events: balancing the flexibility it buys against the risk of making your system's flow impossible to traceSat, 20 Jun 2026 00:00:00 GMTarchitectureevent-drivenmessagingNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/systems/gpu-finops-with-ebpf/https://sade.dev/en/systems/gpu-finops-with-ebpf/Why GPU spend is invisible to cgroup and cAdvisor metrics, and how eBPF attributes GPU time and memory to teams for chargeback — with the honest limit at the CUDA boundary that DCGM has to cover.Sat, 20 Jun 2026 00:00:00 GMTebpfgpufinopsobservabilitykubernetesSysteminfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/systems/zero-static-authority-multi-cluster-gitops/https://sade.dev/en/systems/zero-static-authority-multi-cluster-gitops/GitOps across many Kubernetes clusters with no long-lived kubeconfig or token. SPIFFE IDs, SPIRE-issued short-lived SVIDs, trust-domain federation — the order to build it in, and what each step costs.Sat, 20 Jun 2026 00:00:00 GMTkubernetesgitopsspiffesecurityarchitectureSysteminfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/replaying-a-dead-letter-queue/https://sade.dev/en/notes/replaying-a-dead-letter-queue/The DLQ filled up during an outage and you want it back. Naive replay re-poisons the queue or double-fires side effects. The safe shape: reset, dry-run, sandbox-first, select.Fri, 19 Jun 2026 00:00:00 GMTqueuedead-letter-queuereliabilityoperationsarchitectureNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/systems/polyglot-queue-distributed-tracing/https://sade.dev/en/systems/polyglot-queue-distributed-tracing/A message crosses PHP, Go and Python over a frozen envelope. Turning its journey into one OpenTelemetry trace with no new field and no core dependency — and the honest limit of that.Fri, 19 Jun 2026 00:00:00 GMTopentelemetryobservabilitydistributed-tracingmessagingarchitectureSysteminfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/validate-schema-at-the-edge/https://sade.dev/en/notes/validate-schema-at-the-edge/A message's data is an untyped contract the queue won't check. Validate it at the edge: producer-side before publish, consumer-side as a safety net, against a per-URN schemaThu, 18 Jun 2026 00:00:00 GMTqueueschemareliabilityarchitectureNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/architecture-decisions-rot/https://sade.dev/en/journal/architecture-decisions-rot/An architecture decision written in a wiki is a wish. The boundaries you can't enforce are the ones that quietly erode — until the diagram stops matching the code. Make the rule executableThu, 18 Jun 2026 00:00:00 GMTarchitecturegovernanceopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/idempotency-duplicate-delivery/https://sade.dev/en/notes/idempotency-duplicate-delivery/At-least-once delivery means a handler will see the same message twice. The idempotency key, where it comes from, and the dedupe that survives a crashWed, 17 Jun 2026 00:00:00 GMTqueuereliabilityarchitectureasyncNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/ai-didnt-remove-the-bottleneck/https://sade.dev/en/journal/ai-didnt-remove-the-bottleneck/Cheap code production doesn't raise throughput if review, integration, and verification can't keep up. The bottleneck just moves downstream — and that's where the work now isWed, 17 Jun 2026 00:00:00 GMTai-workflowproductivityopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/flaky-tests-and-determinism/https://sade.dev/en/journal/flaky-tests-and-determinism/AI made writing tests nearly free and flaky suites exploded. Why retry and quarantine are a treadmill, and what catches flakiness deterministicallyWed, 17 Jun 2026 00:00:00 GMTtestingciaiqualityJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/schema-evolution-without-breaking/https://sade.dev/en/journal/schema-evolution-without-breaking/A message's data shape is a contract across services you can't change atomically. The rule: additive is safe, a breaking change needs a new identity — and consumers upgrade firstWed, 17 Jun 2026 00:00:00 GMTarchitectureschemaqueueopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/can-you-ship-vibe-coded-to-production/https://sade.dev/en/journal/can-you-ship-vibe-coded-to-production/Vibe coding lowers the cost of a first version, not the cost of being wrong. That bill arrives in production, not at build time — and it depends on whose hands shipped it.Sat, 13 Jun 2026 00:00:00 GMTai-workflowvibe-codingproductionarchitectureopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/layered-vs-clean-architecture/https://sade.dev/en/journal/layered-vs-clean-architecture/Why the classic layered structure is enough for most projects while we drown in abstraction layers, and when Clean Architecture actually pays off.Sat, 13 Jun 2026 00:00:00 GMTarchitectureclean-architecturesimplicityopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/the-cost-of-just-in-case-code/https://sade.dev/en/journal/the-cost-of-just-in-case-code/Applying YAGNI in practice: the price of adding flexibility you don't need today, repaid daily in maintenance, readability, and bug surfaceSat, 06 Jun 2026 00:00:00 GMTarchitecturesimplicitydecisionsopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/systems/race-conditions-and-gaps-in-sequential-numbering/https://sade.dev/en/systems/race-conditions-and-gaps-in-sequential-numbering/Generating legally sequential, gap-free numbers with parallel workers: the JIT reservation pattern that solves race conditions and gaps togetherWed, 03 Jun 2026 00:00:00 GMTarchitectureproductionconcurrencyqueueidempotencySysteminfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/when-i-move-to-microservices/https://sade.dev/en/journal/when-i-move-to-microservices/The measured signals that justify moving from a monolith to a distributed architecture — and the common false reasons that say it's still too earlySat, 30 May 2026 00:00:00 GMTarchitecturemicroservicesdecisionsopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/gitflow-vs-github-flow/https://sade.dev/en/journal/gitflow-vs-github-flow/Practical criteria for picking a branching strategy by product model, version count, and deploy rhythm — and how each model breaks in the wrong place.Sat, 23 May 2026 00:00:00 GMTgitworkflowbranchingdecisionsopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/when-i-switch-to-trunk-based/https://sade.dev/en/journal/when-i-switch-to-trunk-based/Why release branches break for high-frequency deploy teams and how much of trunk-based is really discipline — the thresholds I cross and the ones I don'tSat, 23 May 2026 00:00:00 GMTgitworkflowdeploydecisionsopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/why-i-start-with-a-modular-monolith/https://sade.dev/en/journal/why-i-start-with-a-modular-monolith/The case for drawing clean module boundaries inside a single deployable app before jumping to microservices — and when I stop doing it.Sat, 23 May 2026 00:00:00 GMTarchitecturemodular-monolithdecisionsopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/systems/data-intensive-systems-breaking-points/https://sade.dev/en/systems/data-intensive-systems-breaking-points/As data load grows, where does boring architecture break? Working set, read replicas, partitioning, write load and a separate data layer — the breaking points in order, and what each one costsWed, 20 May 2026 00:00:00 GMTpostgresqlarchitectureproductionscalingreplicationSysteminfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/why-boring-architecture/https://sade.dev/en/journal/why-boring-architecture/The pragmatic case for choosing proven tools over chasing new technology. This is not cowardice, it is a budget decision.Fri, 15 May 2026 00:00:00 GMTarchitecturedecisionsopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/shared-redis-namespace-isolation/https://sade.dev/en/notes/shared-redis-namespace-isolation/The pattern I use to avoid key collisions and TTL accidents when a single Redis instance is shared across several projectsTue, 12 May 2026 00:00:00 GMTredisproductionarchitectureNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/journal/ai-assisted-engineering-workflow/https://sade.dev/en/journal/ai-assisted-engineering-workflow/The seven rules I follow to use Claude Code and similar agents on production code with confidence — not a skeptic, a discipline manifestoSun, 10 May 2026 00:00:00 GMTai-workflowproductivityopinionJournalinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/pgbackrest-postgresql-backup-strategy/https://sade.dev/en/notes/pgbackrest-postgresql-backup-strategy/pg_dump alone is not a backup. A PITR-capable, compressed, verifiable backup architecture with pgBackRestFri, 08 May 2026 00:00:00 GMTpostgresqlbackupproductionpgbackrestNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/laravel-queue-production-slowdown/https://sade.dev/en/notes/laravel-queue-production-slowdown/Laravel queue workers are flawless locally and slow in production. The five most common reasons developers overlookSun, 03 May 2026 00:00:00 GMTlaravelqueueproductionredisNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/systems/single-vps-multi-project-architecture/https://sade.dev/en/systems/single-vps-multi-project-architecture/One VPS, several independent apps. Deliberate minimalism over Kubernetes: user isolation, separate PHP-FPM pools, shared PostgreSQL/Redis, a plain deploy.Thu, 30 Apr 2026 00:00:00 GMTvpsarchitecturenginxpostgresqlredisSysteminfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/nginx-php-fpm-pool-separation/https://sade.dev/en/notes/nginx-php-fpm-pool-separation/The concrete benefits of defining a separate pool per application instead of a single PHP-FPM pool when running multiple PHP apps on one VPSSun, 26 Apr 2026 00:00:00 GMTnginxphp-fpmproductionvpsNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/systems/laravel-production-stack/https://sade.dev/en/systems/laravel-production-stack/A production-grade Laravel setup with Nginx + PHP-FPM + Redis + PostgreSQL + Supervisor + Horizon. Each piece job and what you lose if you drop itWed, 22 Apr 2026 00:00:00 GMTlaravelphpproductionarchitectureSysteminfo@muhammetsafak.com.tr (Muhammet Şafak)https://sade.dev/en/notes/pgbouncer-auth-query/https://sade.dev/en/notes/pgbouncer-auth-query/A practical setup for dynamic user authentication via `auth_query` instead of `userlist.txt` when running pgBouncerSun, 19 Apr 2026 00:00:00 GMTpostgresqlpgbouncerproductionNoteinfo@muhammetsafak.com.tr (Muhammet Şafak)