Deloitte / NHS
Multiple high-impact features for UK Government and Healthcare institutions, scaling COVID-19 testing infrastructure from 1M to 6M tests per week across a 37-repository serverless architecture.
The challenge
The UK's public health infrastructure needed rapid digitization during the pandemic — testing, registration, communications, and data management all needed to scale from scratch to national capacity. The system had to handle millions of test results weekly while maintaining strict data governance, accessibility compliance, and integration with existing government services.
My role
I built core platform services and reusable libraries across the 37-repository architecture, led small teams of 3–4 developers, and designed authentication and circuit breaker patterns adopted across the organization. My work directly contributed to scaling the platform from 1M to 6M tests per week.
System architecture
What I built
Distributed circuit breaker implementation using Redis as shared state store across Lambda invocations. The pattern prevents cascade failures when downstream services degrade, with configurable thresholds, half-open probing, and automatic recovery that reduced system-wide outage impact.
ResilienceReusable request signing library implementing AWS Signature Version 4 for secure service-to-service communication. Adopted across the organization, it increased developer productivity by 80% by eliminating manual auth configuration and providing consistent credential management.
SecurityMulti-mechanism API Gateway authorizer supporting JWT, JWKS, API keys, and service tokens through a single Lambda function. Consolidated authorization logic that was previously duplicated across services into one auditable, testable component.
Auth platformShared validation service ensuring test kit barcodes conform to format rules, uniqueness constraints, and lifecycle state before entering the processing pipeline. Prevented invalid samples from consuming downstream compute resources and generating false results.
Data integrityStream-based architecture processing test results from laboratory systems through validation, enrichment, and notification stages. DynamoDB streams trigger downstream workflows, enabling near-instant result delivery to patients and public health dashboards.
Core pipelineAutomated workflow for bulk test kit registration, linking physical kits to digital records before distribution. Eliminated manual data entry for large-scale testing programs and reduced patient management time from 3 hours to 5 minutes per batch.
OperationsTechnologies used
Key achievements
- Scaled testing from 1M to 6M tests per week
- Reduced patient management time from 3 hours to 5 minutes
- Built reusable circuit breaker and auth libraries
- Increased developer productivity by 80% with SIGv4 library
- Led teams of 3–4 developers across multiple projects
- Reduced data processing stagnation by 99%