- FastAPI – What It Is and Why It Exists
Start here. What FastAPI actually gives you — validation, serialisation and OpenAPI docs derived from ordinary type hints — and what it does not. Installing it, a first endpoint, what /docs is really reading, and how a request travels through the ASGI stack. Then the lesson index in reading order, the versions this track is written against, and the booking API every example is taken from.
- Designing an Airline Booking System
Flight booking, which is the seat-hold problem from the concurrency post at a much harder scale. Searching a graph of routes rather than a list of rows, fare classes and the inventory buckets that make pricing possible, holding a seat while payment completes, deliberate overbooking as a business rule, PNRs and ticketing, integration with systems older than the web, and what happens when a storm cancels four hundred flights at once.
- AWS – CodeBuild: buildspec, Caching and Build Speed
The buildspec file phase by phase, what each one is actually for, and the artifacts block that decides what the next stage receives. Then the two things that make builds slow and expensive: no dependency cache, and a compute type chosen by guessing. Local caching versus S3 caching, environment variables that should be parameter references, and privileged mode for building a container image.
- AWS – CodePipeline: Stages, Artifacts and Approvals
A pipeline is stages, and between them an artifact in an S3 bucket — get that one idea and the rest is configuration. Source from GitHub through a CodeStar connection rather than a token, build, a manual approval gate, deploy. Where CodePipeline beats GitHub Actions and where it plainly does not, and the input-artifact mismatch that is the single most common reason a stage fails with nothing useful in the log.
- MongoDB – Spring Data MongoDB
The Java side: repositories versus MongoTemplate, how mapping works, where to declare indexes, and the field rename that catches everyone.