Topic 04 Professional experience · Business rules · Tests · Production
Backend engineering and quality
I made a central contribution to Rails API development, data modeling and business rules, with tests, reviews and refactoring. My work also spanned interfaces, mobile and production, connecting backend development with the system behavior the team needed to maintain and evolve.
Context
I have worked on API development and maintenance, with a central backend contribution and involvement in other stages of development.
The focus here is quality during evolution: understanding a rule, protecting its behavior and investigating what happens in operation.
Problem
A rule can be spread across models, services and persistence. Changing only its most visible point can leave inconsistencies in other paths.
A test that merely repeats the implementation can keep passing even when the user experience is wrong.
My contribution
I built and evolved Ruby on Rails REST APIs, modeled relational data and implemented business rules with automated tests. My contribution was central on the API within a team effort.
I took part in reviews, refactoring and defining technical standards, alongside legacy interface maintenance and React modernization.
I also contributed to mobile, DevOps and production follow-up through observability and error tracking, maintaining direct communication with international clients in English.
Technical criteria
I combined implementation, code review and refactoring when evolving the backend. I treated validation, data integrity and behavior tests as part of a feature rather than disconnected delivery stages.
That work informs my current criteria: place each rule in an understandable responsibility, separate evidence from hypotheses during investigation and protect a fix with a regression test.
Alternatives and trade-offs
General criteria and technical analysis written for this portfolio.
- Tests tightly coupled to internal structure make refactoring costly. Overly broad tests can make a failure’s cause hard to locate.
- Refactoring and changing behavior at the same time increases the review surface. I prefer separating those intentions when it makes verification clearer.
Application and examples
Educational example: a task list accepts completion of an item only when its required fields are valid.
Observable rule
Describe what a person can do and which response they receive when information is missing.
Behavior test
Verify acceptance and rejection through the rule’s public interface, without depending on helper method names.
Focused review
Check validation, persistence and error responses, looking for paths that might bypass the rule.
Operational diagnostics
Use error evidence and enough context to reproduce the problem without logging unnecessary sensitive data.
What this experience demonstrates
My contribution connected APIs, business rules, tests and interfaces while evolving production systems. I worked on features and fixes as well as review, refactoring and technical-debt reduction.
The example illustrates validation, tests and review with fictional data. It does not reproduce a professional business workflow.