Capstone project for How the Web Works

Design brief: delivery tracking in the Partner app

Mangrove Market's Partner app lets about 1,800 independent corner shops order stock wholesale from its 4 distribution centres. Shop owners phone the DCs all day asking "where is my delivery?". Imran wants a feature where a shop sees its open orders, each order's status (packed, on the truck, delivered) and an expected arrival time, and confirms receipt with a count of cartons, which updates the shop's invoice. Many shops run on patchy mobile data, and order volume triples in the week before a festival. Write the design brief Imran will take to the design review: requirements with numbers, the API, a capacity estimate, the network budget for the main screen, and the SLOs. Use the lessons' templates and your own reasoned assumptions where a number is missing.

What you hand in

A requirements sheet: 3 to 5 FRs, at least 6 NFRs with numbers, an out-of-scope list and open questions
An API contract for 3 to 5 endpoints: methods, paths, status codes, one error shape, cursor pagination and a receipt confirmation that is safe to retry
A back-of-the-envelope estimate of peak requests per second and yearly storage, with every assumption listed
A network budget for the open-orders screen on a 200 ms mobile link: calls, round trips and total time
An SLO document for the two most important endpoints, with an error budget policy

Check your work

Tick each item when your project meets it. Be strict: this is the rubric the reviewer uses.

Every NFR has a number, a unit and where it is measured, and at least one covers the festival week
Endpoints use nouns and the right methods, and 4xx and 5xx codes are used honestly
The order list uses a cursor and has a maximum page size
Confirming receipt is safe to retry: one idempotency key per action, stored with a unique constraint
The estimate shows its arithmetic, uses a peak factor, and says what the numbers mean for the design
The open-orders screen needs at most one or two round trips once the connection is open, or the brief explains why not
Each SLO is a ratio of good events with a latency limit and a window, and the targets differ by business impact
The brief names its trade-offs and what would change if the numbers grew ten times

0 of 8 checked

Model answer

The model answer opens once your capstone passes the review, so you can compare your work with an outline of a strong submission.

Hand in your capstone

Your links are checked automatically, then the work is scored against the rubric above, item by item, with comments. A pass counts toward the course certificate and shows on your profile.

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