An incremental API sync needs a stable progress model, explicit deletion handling and reconciliation after interruptions. Fetching every page once does not prove completeness when the source changes during the run. Define cursor or watermark behaviour from the provider's documented contract rather than inventing assumptions about ordering.
Let’s plan your incremental sync plan.
Bring your workflow, constraints and open questions. We’ll help you define the requirements and work through a practical next step.
Establish the source capabilities
Check supported pagination, sort guarantees, change timestamps, deletion events and cursor expiry. Identify whether the source provides a consistent snapshot or a moving collection. Record limits and unsupported cases.
For a hypothetical customer sync, editing an old record can matter as much as adding a new one. A process that only requests larger identifiers may miss those updates entirely.
Create a progress and recovery matrix
| Condition | Design question | Acceptance case |
|---|---|---|
| Source changes between pages | Is the page population stable? | Concurrent insert or update |
| Equal update timestamps | How are ties handled? | Several records at the boundary |
| Worker stops | Which progress is durably accepted? | Restart after partial processing |
| Cursor expires | What supported recovery exists? | Resume after a long delay |
| Record deleted | How is removal represented? | Destination does not retain a false active copy |
| Permission narrows | Is missing data deletion or restricted access? | Access-change scenario |
Never interpret absence from one page as proof that a record was deleted. The reason may be pagination, filters, permission or an incomplete response.
Commit progress carefully
Keep received records and accepted destination outcomes traceable. Advance a checkpoint only under the agreed processing rule. Advancing before durable acceptance can skip work after a crash; advancing too late without duplicate protection can repeat it.
Use overlap or replay only where the destination can handle it safely. Do not claim exactly-once processing from a timestamp comparison alone.
Reconcile and expose limits
Periodically compare an authorised source population with destination state using the provider's available capabilities. Document gaps where complete reconciliation cannot be established.
Show sync age and unresolved exceptions to operators. A recurring task marked successful can still have missing records if its completeness checks are weak.
Incremental-sync questions
Is page-number pagination always unsafe?
No. Assess the source's snapshot and ordering contract. The risk depends on how the collection changes and what the API guarantees.
Can a deletion event be replayed freely?
Apply the defined record and version rules. A stale event must not remove a legitimately recreated or changed destination record.
Pair this design with schema-change handling, and review the contract with Drema's API team.
