You get a document, not a call.
I read the code, the schema and the query plans, run a profiler against the paths that matter, and write down what is actually slow and why. Every finding comes with the condition that triggers it, the effort to fix it, and what it buys you. The list is ordered by impact, so you can stop reading after item three and still have done the useful part.
The things I usually find:
N+1 queries behind a page that looks innocent.
A synchronous call to somebody else's API inside the request, holding a worker for three seconds. At any real traffic that is arithmetic, not a language problem.
No request budget, so one slow dependency drains the pool and takes the site with it.
An index that was never added to a table that only grows, and cache invalidation that quietly does nothing.
I will also tell you what not to touch, and what I could not establish without production access. If the fix is a query plan I will say so rather than propose a rewrite in another language, which is how the last three of those conversations ended for me.
Stack: PHP 8 with Symfony or Laravel, Node and TypeScript, PostgreSQL, MySQL, Redis, ClickHouse. Report in three to five working days depending on size. Fixes are quoted separately from the report, and you are free to take the report elsewhere. A redacted sample of the method is attached below.
