How a High-Growth Company Modernized Critical Production Workflows by Introducing Temporal Alongside Legacy Systems

Executive Summary

A construction workforce management platform faced recurring reliability failures in its most critical production workflows: worker check-in and check-out. Precise time capture was non-negotiable, directly impacting payroll accuracy, compliance reporting, site access control, and operational analytics. The company’s on-premises architecture had become a ‘fragile brain’ at the center of operations. Tightly coupled databases and middleware meant that a single service hiccup caused cascading retry storms and system-wide paralysis. Even brief outages created orphaned state and hidden workflow failures. Without durable execution, temporary glitches turned into permanent data corruption, forcing engineering teams into on-call fatigue just to manually reconcile database rows.

Xgrid’s Solution: Rather than pursuing a high-risk, full-system rewrite, Xgrid applied a surgical, strangler fig inspired modernization approach using Temporal. Only the mission-critical attendance workflows were migrated to Temporal, while the remainder of the legacy system continued operating unchanged. This strategic precision enabled a zero-downtime migration, guaranteed completion of every attendance workflow, and created a repeatable playbook for incrementally modernizing additional system components—without disrupting live production or regulatory compliance.

The Challenge

The platform’s core responsibility—accurate workforce tracking—was inherently mission-critical. Failures carried immediate financial, legal, and trust implications.

Mission-Critical Workflows with Fragile Infrastructure:

The legacy system relied heavily on a “database-as-queue” pattern with limited failure recovery. Network interruptions, service restarts, or partial outages frequently left workflows in indeterminate states. Workers could remain “checked out” or “checked in” incorrectly, requiring manual investigation and correction.

Multiple Single Points of Failure:

The tightly coupled on-premises architecture exposed failure risks across several layers: the primary database, ERP integrations, and intermediary middleware services. When a failure occurred mid-transaction, the system lacked deterministic recovery mechanisms, leading to data divergence and inconsistent worker records.

Business Impact of System Downtime:

Technical failures translated directly into real-world consequences. Field workers were sometimes flagged as late or absent due to system unavailability rather than actual behavior. This eroded trust, increased dispute resolution costs, and introduced potential labor compliance liabilities.

Risk-Averse Migration Requirements:

Given regulatory requirements around time tracking and the continuous nature of construction operations, a traditional “big-bang” migration—requiring downtime or parallel system freezes—was not an option. Any modernization effort had to operate safely within a live production environment.

The Solution: Surgical Modernization with Temporal

Xgrid designed a modernization strategy centered on Temporal’s Durable Execution model, treating each worker’s shift lifecycle as a reliable, long-running Entity Workflow.

Targeted Workflow Migration Strategy:

The scope was intentionally narrow. Only check-in and check-out workflows were extracted and reimplemented on Temporal. All non-critical functionality—including reporting, administrative tooling, and downstream analytics—remained on the legacy platform, significantly reducing risk and delivery time.

Guaranteed Execution for Attendance Operations:

Temporal’s durable workflows ensured that every check-in and check-out was completed exactly once. Transient failures—such as database unavailability or ERP timeouts—were handled automatically through retries and state persistence, without operator intervention or data loss.

The ‘Safety-Net’ Dual-Write Pattern:

To eliminate the fear of a production cliff, Xgrid implemented a battle-tested dual-write blueprint. Attendance events were persisted simultaneously to the new durable workflow and the legacy system, creating a zero-risk rollback path that satisfied even the most conservative risk models.

Incremental Module Migration Framework:

The initial success established a repeatable blueprint: identify a high-impact workflow, migrate it to Temporal, integrate with legacy systems, validate reliability, and move on to the next module. This transformed modernization from a one-time risk into a controlled, ongoing process.

Hybrid Cloud for Security and Scale:

Temporal Cloud served as the orchestration control plane, while on-premises workers executed business logic and accessed sensitive systems. All outbound communication originated from within the customer’s environment, preserving data residency and security constraints while gaining cloud-level reliability.

Observability and Monitoring Platform:

Deep integration with Grafana and Prometheus delivered real-time visibility into workflow execution, failure patterns, latency, and throughput—replacing reactive troubleshooting with proactive operational insight.

Implementation Highlights

Results: Production Reliability Without Disruption

Operational Reliability

Zero Failed Check-Ins:
Temporal guaranteed completion of every attendance workflow, eliminating erroneous late or absent records caused by system failures.

Automatic Recovery:
Workflows resumed seamlessly after interruptions, retrying failed operations without losing execution state or requiring manual intervention.

Data Consistency:
The dual-write approach maintained full consistency across new and legacy systems, removing the need for manual reconciliation efforts.

Migration Success

Zero Production Incidents:
The migration was executed without downtime, despite thousands of daily active users and continuous field operations.

Transparent User Experience:
No frontend changes were required. Workers and site managers continued using the same interfaces, unaware of the backend transformation.

Repeatable Pattern Established:
The attendance migration became a proven template for modernizing additional workflows with confidence.

Observability Improvements

Real-Time Visibility:
Operations teams gained immediate insight into workflow status and failures, replacing delayed discovery through audits or support tickets.

Proactive Alerting:
Prometheus-based alerts surfaced anomalies before they escalated into business-impacting incidents.

Analytics Dashboard:
Grafana dashboards delivered actionable insights into attendance behavior, system performance, and capacity planning.

Operational Outcomes

Risk-Free Modernization:
Critical workflows were modernized without jeopardizing production stability or regulatory compliance.

Eliminated Manual Reconciliation:
Operational overhead caused by inconsistent data and failed transactions was effectively removed.

Worker Trust Restored:
Accurate, reliable time tracking rebuilt confidence among field workers and reduced dispute resolution.

Foundation for Future Migrations:
The organization now has a clear, low-risk path for continued modernization.By implementing proper observability from Day 1, our team avoided the ‘Day 90 Cliff’ where hidden workflow failures usually start burying operations teams.

Lessons Learned

• Incremental migration dramatically reduces risk compared to full-system rewrites.
• Prioritizing high-impact workflows delivers immediate business value and internal buy-in.
• Temporal’s durable execution model replaces complex, error-prone custom recovery logic.
• Dual-write strategies are essential for confidence and compatibility during transitions.
• Legacy coexistence is an advantage, not a compromise, when continuity matters.

Looking Ahead

The established framework is now being extended to additional critical domains:

• Tool and Equipment Management: Reliable tracking of assignments and returns to reduce loss
• Safety Compliance Workflows: Durable certification and training verification
• Payroll Integration: Direct orchestration between attendance and payroll systems
• Project Lifecycle Management: End-to-end orchestration of approvals, staffing, and resources
• Legacy System Decommissioning: Gradual retirement of on-premises systems as modules migrate

The Xgrid Advantage

• Zero-Downtime Migrations: Surgical workflow extraction without maintenance windows
• Guaranteed Workflow Completion: Deterministic execution despite downstream failures
• Legacy System Compatibility: Seamless integration without forced replacement
• Incremental Modernization: Business-prioritized migration at controlled risk
• Production-Tested Patterns: Proven strategies that accelerate delivery
• Comprehensive Observability: Full visibility from day one

We didn’t just fix a workflow; we helped the team survive the ’90-Day Cliff’ where most modernizations fail. By delivering a production-ready blueprint instead of just code, we ensured the system remained stable long after the initial launch.

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