Sync & Conflict Resolution
Two devices that both changed the same record while neither could see the other.
4 to work through
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advanced
A field application has been live for three months and support reports that engineers occasionally lose completed job reports. What do you investigate?
2 min answer -
advanced
A field-service app syncs with a change cursor. Support reports that three customers see cancelled jobs reappearing months after they were closed, and every affected engineer had been on extended leave. The sync endpoint returns 200 for these devices and the client reports no errors. Where do you look, in what order?
2 min answer -
advanced
A file sync product loses user edits during a conflict. What are the likely design failures?
1 min answer -
advanced
An offline-first app has users who have not opened it in eight months. You need to change the local schema. How?
2 min answer
4 terms in this topic
Conflict Copy
Preserving both sides of a sync conflict as separate artefacts rather than choosing a winner - the only resolution strategy that never loses user work.
patternLast Writer Wins
Resolving a conflict by keeping the version with the later timestamp — simple, deterministic, and it silently discards the other change.
conceptResync Horizon
The age of the oldest change a server can still describe as a delta - beyond which a returning client must take a full snapshot or it will silently k…
conceptSync Conflict Resolution
The policy applied when the same record was changed on two devices while they were disconnected, and both changes now arrive.
Neighbouring topics
Edge, Mobile & IoT
General material on architecture beyond the data centre boundary.
Mobile App Architecture
Layering, navigation, background execution, and the platform rules you do not set.
Offline-First
Treating connectivity as an optimisation, with a local store as the source of truth.
CRDTs
Data types that converge without coordination, and the semantics you must accept.
Mobile Release Strategy
Store review, staged rollout, and supporting versions you can never force off.
Push & Background Work
Delivery that is best-effort, and an operating system that will kill your process.
Device Identity
Identifying a thing rather than a person, and rotating a credential you cannot type.
Edge Compute Topologies
Regional, metro, on-premises and on-device, and what each tier is genuinely for.
Edge Functions
Short-lived compute at the CDN, its runtime limits, and what must stay at origin.
Edge Data Consistency
Replicated read state at hundreds of locations, and writes that still go to one.
IoT Ingest Architecture
Millions of small, unreliable, frequently duplicated messages arriving continuously.
Device Provisioning
Getting identity and configuration onto hardware at manufacture or first boot.
Fleet Management
Inventory, health, configuration and grouping across devices you will never see.
OTA Updates
Updating firmware over a flaky link, with rollback, and without bricking the device.
Constrained Protocols
MQTT, CoAP and their kin, chosen for power, packet size and intermittent links.
Device Telemetry at Scale
Deciding what a device sends, how often, and what is aggregated before it leaves.
Digital Twin
A server-side model of a physical thing's reported and desired state.
Edge Security & Attestation
Secure boot, hardware roots of trust, and proving what is running on a device.
Physical-World Failure Modes
Power loss, tampering, clock drift, thermal limits, and a truck through the fibre.