Fermin Quant Senior Software Engineer · Ottawa

Case studies

Examples that go from problem to decision.

Each case study focuses on one decision space: the problem, the constraint that made it awkward, the shape I chose, and the tests or code that keep the behavior testable. They avoid client code and proprietary implementation detail. The Redis case is a sanitized reconstruction of professional work, with a separate companion repository instead of employer code.

01 Backend APIs REST APIs

Approval workflow API walkthrough

A backend API case study about the parts that can quietly drift apart: workflow rules, request and response contracts, code structure, and testable behavior.

  • Three guided scenarios: happy path, business-rule rejection, unauthorized actor
  • Endpoint contract, request and response shapes, and error model
  • Implementation excerpts with the tests that cover each path
  • Tradeoffs around separation of duties and audit history
Open the case study REST APIs skill page
02 Cloud & DevOps AWS CDK

CDK construct library for durable serverless workflows

A cloud/platform case study about the point where repeated AWS wiring becomes worth turning into reusable CDK constructs.

  • Before-and-after CDK comparison from the developer's point of view
  • Six custom constructs for state, queueing, API wiring, workers, notifications, and alarms
  • The AWS shape generated by API Gateway, Lambda, DynamoDB, SQS/DLQ, SNS, and CloudWatch
  • Unit tests, construct tests, assertion tests, and local synth results
Open the case study Open source repository AWS CDK skill page
03 Cloud & AWS Event-driven operations

Operating an event-driven workflow under failure

A cloud/platform case study about keeping async work understandable after the request has already been accepted.

  • Failure scenarios for retry, DLQ, idempotency, and backlog latency
  • The same workflow behavior expressed in C# and TypeScript
  • Telemetry events tied to correlation IDs and runbook output
  • CDK assertions for API, queues, DLQ, alarms, dashboard, and role-scoped permissions
Open the case study Open source repository AWS CDK skill area
04 Cloud & AWS Redis/ElastiCache

Redis/ElastiCache platform caching across serverless apps

A cloud/platform case study about making Redis usable by multiple serverless services without shared credentials, hidden configuration, or cache key collisions.

  • Shared ElastiCache Serverless foundation with endpoint and user-group metadata
  • Per-service Redis users, generated secrets, and keyspace-scoped access strings
  • Lambda connection configuration with a predictable REDIS_SECRET_ARN boundary
  • Downstream application migration steps and public-safe companion tests
Open the case study Open companion repository Redis/ElastiCache skill page
05 DevOps & Delivery CI/CD modernization

Trunk-based delivery modernization

A CI/CD modernization case study about smaller batches, earlier feedback, and the gates that keep trunk-based delivery from becoming reckless.

  • Release-branch to trunk-based delivery comparison
  • Short-lived branch policy, feature-flag tradeoffs, and mainline quality gates
  • Executable delivery gate model with scenario reports
  • Pipeline YAML, test mapping, and production rollout notes
Open the case study Open source repository CI/CD skill page
06 Consulting & Leadership Architecture communication

Standardizing async workflows across teams

A consulting and leadership case study about standardizing repeated async workflow choices without over-centralizing team ownership.

  • Decision criteria for repeatability, operability, ownership, and reversibility
  • Service-specific, construct-library, and central-platform options compared
  • Engineering detail, delivery impact, and team-adoption wording
  • Adoption model, opt-out conditions, and signals for a future platform service
Open the case study Architecture communication skill page