apex-async-integration

Apex Async & Integration

Decision tree

• Small deferred unit of work -> Queueable.
• Very large data set -> Batch Apex or an external bulk-processing mechanism.
• Time-based execution -> Schedulable, usually delegating to Queueable/Batch.
• Legacy/simple async requirement -> @future only when its constraints fit; do not introduce it by default.
• Event-driven decoupling -> Platform Events / Change Data Capture when appropriate.
• External HTTP callout -> Named Credential / External Credential plus an async boundary if the invocation context cannot perform a callout.

Queueable

• Pass only serializable, bounded state.
• Avoid chaining indefinitely.
• Design idempotency when retries or duplicate execution are possible.
• Make failure handling observable.

Batch

• Choose batch size deliberately based on query shape and per-record work.
• Keep each execute scope independently safe.
• Avoid stateful mode unless accumulated state is necessary.
• Make finish behavior explicit.

Callouts

• Use Named Credentials/External Credentials for authentication.
• Set timeouts deliberately.
• Validate response status and payload.
• Avoid logging secrets or sensitive payloads.
• Define retry policy only for transient failures; do not blindly retry permanent validation/authentication failures.
• Design idempotency for operations that can be retried.

Failure model

Document:

• transient vs permanent errors;
• retry count/backoff;
• dead-letter/manual recovery path;
• transaction rollback behavior;
• user-visible status;
• monitoring/logging.