The engineering notebook
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Articles, practical guides, and engineering notes on idempotency.
By Ashish Bhakhand 108 published articles
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9 articles
Reset filtersReliable Webhooks with Authentication, Deduplication, and Reconciliation
Turn provider callbacks into durable, idempotent state changes that remain correct across retries and delayed events.
Safe MongoDB Writes with Unique Indexes and Atomic Upserts
Replace check-then-write races with database-enforced uniqueness, conditional updates, and deliberate duplicate handling.
Building Resumable Backfills Instead of One Giant Sync
Process historical data in bounded windows with durable progress, overlapping retries, and idempotent writes.
Idempotent Mobile Health Backfills Across Reinstalls and Devices
Use semantic identities and natural keys so repeated health imports repair missing history without inflating aggregates.
Resumable One-Year HealthKit Backfills
Import long health histories in bounded windows with durable progress and idempotent writes.
Designing Stable Health Sync Identities Across Android Devices
Prevent duplicate history by deriving server identity from semantic data instead of installation-local rows.
Optimistic Chat UI with Idempotent Server Turns
Show messages immediately while reconciling acknowledgements, streamed text, persistence, failures, and safe retries.
Why Automatic Retries Are Dangerous for Swift API Clients
Retry transient reads with bounded jitter while protecting writes from duplicate business effects.
Idempotency Is Not Optional in Serverless Systems
Retries are normal in distributed systems. Design writes so repeated requests and messages do not repeat the business effect.