Back-End / API Developer

Real portfolio pieces built during the course, not a certificate for its own sake. Each one is work you can show.

• API specification for one resourceOne resource written down so that somebody could build a client against it without asking you a question: the operations with their methods, status codes and authorisation checks, the paging and filtering rules, real request and response specimens, and an error contract that says for every published code what it means and whether retrying could ever help.
• Data model, decision record and migrationThe tables with the grain of each one stated in a sentence, the columns that need explaining and what each prevents, a decision record naming the cheaper alternative you rejected and the evidence that settled it, and the migration itself with an honest reverse step that says what it restores and what it does not.
• Slow endpoint write upOne page on something you made faster, in the order an interviewer listens for: the symptom and who reported it, which callers were affected and which were not, the row counts, the query plan and the timings before, the cause in one sentence, the change, the same measurement after, what it cost on the write path, how a regression would be noticed, and what you found and deliberately left alone.
• Endpoint test suiteOne endpoint tested properly against a real database: the success case, and the failure cases that outnumber it six to one, each asserting the status code, the body and the state left behind, including the assertion on the rows that a passing set of response checks would otherwise miss.
• API change noteA published contract changed without breaking anybody: what is changing and whether it is breaking, who is affected taken from the access log rather than from memory, before and after specimens, which of two related fields is authoritative, the date it goes live, and what you are deliberately not doing.