Postmortem: Order Placement Slowness on Shopflo Checkout

Incident Status: Resolved

Severity: Degraded Performance

Affected Component: Order Placement (Checkout)

Dependency: Shopify APIs

Summary

Shopflo Checkout experienced slow order placement due to Shopify API slowness. The issue was identified promptly, monitored closely, and resolved after Shopify’s API performance stabilized. All other checkout functionalities continued to work as expected throughout the incident.z

After thorough monitoring, error rates reduced steadily and returned to normal levels, confirming full resolution.

Customer Impact

• Order placement was slower than usual for a subset of users
• No checkout failures or dropped orders
• No data loss
• All other checkout features functioned normally

Root Cause

Shopflo relies on Shopify APIs during the final order creation step. During the incident window, Shopify experienced API latency, causing delays in order placement on Shopflo Checkout.

Incident Timeline

• Issue Identified

  Order placement slowness was identified and attributed to Shopify API degradation.

• Impact Observed

  Order placement requests experienced increased latency.

  All other checkout flows worked as expected.

• Monitoring Phase

  Shopify API performance and Shopflo error rates were continuously monitored.

  Error cases began trending downward as Shopify performance improved.

• Resolved

  After thorough monitoring, Shopify APIs stabilized and order placement speeds returned to normal.

  Error rates normalized and the incident was marked as resolved.

Resolution

No changes were required on Shopflo infrastructure. Once Shopify API performance recovered, order placement latency automatically normalized. Existing retries and safeguards ensured no order loss.

What Went Well

• Fast identification of upstream dependency issue
• Clear isolation of impact to only order placement
• Retry mechanisms prevented failures
• Transparent status page communication

Areas for Improvement

• Faster visibility into upstream API degradation
• Clearer differentiation between latency vs failure alerts

Action Items

• Strengthen monitoring for Shopify API latency spikes
• Improve dashboards for dependency-related incidents
• Refine merchant-facing communication templates
• Evaluate additional resilience during upstream slowness

Conclusion

This incident was caused by Shopify API slowness, an external dependency. Shopflo systems remained stable, no orders were lost, and full recovery was confirmed after extended monitoring. We’ll continue improving observability and communication to minimize impact in similar scenarios.