Idempotency
A duplicate event is acknowledged without a target write, preserving a single target record and unchanged state.
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Synthetic local integration-reliability work sample
SaaS Integration Reliability & Support Troubleshooting
A source-to-target account and entitlement synchronization exercise that makes contracts, mapping, failure handling, recovery, reconciliation, and operator evidence visible.
- Executable authority
- Python reference orchestrator
- Contracts
- Source and target OpenAPI
- Reliability
- Retry, dead letter, replay
- Boundary
- Local synthetic integration
Project proof
Review the executable evidence behind the case study
The problem
A successful API call is not the same as a reliable integration
Account and entitlement changes can repeat, arrive out of order, fail validation or authentication, hit transient target errors, or drift from the source of truth. Without explicit delivery state and reconciliation, a workflow can report success while the target is stale or inconsistent.
This project models those failure paths directly and leaves evidence that a technical reviewer or support analyst can follow.
Architecture and contracts
Keep source truth, delivery state, and target state separate
Each layer answers a different operational question and exposes a bounded local contract.
- 01Source APIValid account and entitlement events
- 02Reference orchestratorValidate, map, order, and retry
- 03Integration stateDelivery, idempotency, and dead-letter history
- 04Target APIOne current entitlement record per account
- 05Structured traceCorrelation and outcome evidence
- 06ReconciliationLatest source state compared with target
Text alternative
Synthetic source events enter a Python reference orchestrator. The orchestrator validates and maps each event, checks idempotency and ordering in integration state, applies bounded target retries, and records the result in a structured trace. Reconciliation compares the latest valid source state with one target record per account.
Reliability decisions
Reject permanent faults early; contain transient faults visibly
Ordering
An event version older than the latest accepted version is ignored before the target is called.
Bounded retry
A transient 429 recovers on the second attempt. Repeated 503 responses stop after the third attempt rather than retrying indefinitely.
Dead letter and replay
Exhausted delivery evidence remains intact. Replay uses the same event identity, a new trace, and an explicit link to the failed delivery.
Executed local evidence
Twelve scenarios make the important edges reviewable
The figures describe deterministic local synthetic tests, not customer or production outcomes.
The test set covers create, tier update, suspension, duplicate delivery, out-of-order delivery, missing data, invalid enum, 429 recovery, 503 exhaustion, authentication rejection, reconciliation mismatch, and dead-letter replay.
Correlation evidence connects the original failed delivery to its replay while preserving the original event identity and one final target record.
Reconciliation
Recovery is complete only when the final state agrees
The final comparison evaluates the latest valid source state against the target by account and field. It detects missing, stale, mismatched, and unexpected target records rather than relying on delivery status alone.
A test-only mismatch is corrected from the latest valid source state through an explicit repair route. The evidence does not invent a higher-version source event or recast the repair as normal delivery.
The final result contains three matching records and zero remaining reconciliation exceptions.
Support and troubleshooting
Turn a failure trace into a bounded operator decision
Authentication rejection
Distinguish a rejected delivery from an absent source record or transient target failure.
503 exhaustion and replay
Confirm bounded attempts, retained dead-letter history, fault clearance, replay lineage, and final target state.
Reconciliation mismatch
Identify the differing field, confirm latest source authority, apply a controlled test repair, and reconcile again.
Ten-topic runbook
Each topic records signal, diagnosis, evidence, action, escalation, recovery, and closure guidance.
Scope
Executable local proof with a clear technology boundary
All records, APIs, failures, traces, and incidents are synthetic and local. This project represents no real customer, client, production integration, live service, enterprise scale, adoption, ROI, SLA performance, or operational ownership.
The Python reference orchestrator is the executable authority. n8n execution was deferred; the included workflow is a structural draft only and does not establish n8n proficiency.