Mobile Portfolio Projects

Short answer

What do mobile reviewers look for?

Mobile reviewers want to install it, or at least watch a screen recording. Offline handling is the differentiator.

Every brief below includes the problem it solves, who would use it, the features to build first, the stretch goals to leave until the core works, the data model, stack options and an honest time estimate — plus what a reviewer can infer from a finished build.

Pick one. Not three. The most common failure on a junior portfolio is several projects at 60% completion, and the fix is choosing a scope you can finish.

Beginner

BeginnerFull-stackMobile

Shared House Expense Splitter

Housemates track shared costs in a group chat and a note on the fridge. By the end of term nobody agrees who owes what.

2 weekends

Who it is for

Shared houses, flatmates, trip groups. Real users are two doors down.

Build this first

Add an expense with a payer, an amount and who it is split between
Uneven splits, not only equal ones
A running balance per person
Settle up, which clears balances and records the settlement
A simple shared view without accounts

Once the core works

Minimise the number of transactions needed to settle everyone
Receipt photo upload
Recurring expenses like rent and bills
Export the ledger as CSV

Data you will need

People, expenses and splits. The balance calculation is derived, never stored — a good discipline to establish early.

Stack options

Any full-stack framework with a small database. Postgres or SQLite.

What a reviewer can infer

Money handled correctly — integer minor units, never floats; Derived state calculated from a ledger; Multi-entity data modelling; Designing for a shared, multi-user flow.

Why this works as portfolio evidence

Money arithmetic is where floating point bites, and handling it in integer cents is a detail interviewers notice. The settle-up minimisation stretch goal is a genuine little algorithm you can talk through on a whiteboard.

BeginnerFront-endFull-stackMobile

Spaced-Repetition Flashcards

Revising by re-reading notes is close to useless, and the good spaced-repetition tools have a steep learning curve for one module's worth of revision.

2 weekends

Who it is for

Students revising anything with facts in it — you, and everyone on your course.

Build this first

Create decks and cards with a front and a back
A review session that shows cards due today
Rate recall, and schedule the next review from that rating
Track how many cards are due and how many were reviewed
Import cards from pasted text or CSV

Once the core works

Implement the SM-2 scheduling algorithm properly
A statistics view of retention over time
Images on cards
Offline support with a service worker

Data you will need

Decks, cards, and a review history per card. The scheduling state is the interesting part of the model.

Stack options

Any front-end framework; add a back end only if you want cross-device sync.

What a reviewer can infer

Implementing a published algorithm from its specification; Date scheduling and interval arithmetic; Session and progress state; Data import and parsing.

Why this works as portfolio evidence

Implementing SM-2 from the original description is exactly the kind of task a junior developer is given: read a spec, translate it into code, verify it behaves. Being able to explain that scheduling algorithm is a strong interview moment.

Intermediate

IntermediateMobile

Workout Tracker (Mobile)

Tracking gym sessions in a notes app means no history, no progression and no way to see whether anything is improving.

3–4 weeks of evenings

Who it is for

Anyone lifting regularly and trying to progress.

Build this first

Define workout templates with exercises, sets and reps
Log a session against a template, entering weights as you go
History per exercise, with a progression chart
Works fully offline
Rest timer between sets

Once the core works

Sync across devices when a connection is available
Personal-record detection and notifications
Import and export data as CSV or JSON
Apple Health or Google Fit integration

Data you will need

Exercises, templates, sessions and set entries. Local-first storage with an optional sync layer.

Stack options

React Native or Expo, Flutter, Swift or Kotlin. SQLite locally, whatever you prefer for the optional sync back end.

What a reviewer can infer

Offline-first data with a local database; Mobile navigation and platform interface conventions; Charting time-series data; Designing for one-handed use in a noisy environment.

Why this works as portfolio evidence

Offline-first is a real architectural constraint and it forces genuine decisions about conflict resolution. Mobile portfolios are also less crowded than web ones, so a finished, installable app stands out.

Other tracks

Front-end portfolio projects — Interface work where the difficulty is in state, accessibility and performance rather than in the styling.
Back-end portfolio projects — APIs, data modelling, concurrency and the infrastructure that keeps a service standing up.
Full-stack portfolio projects — End-to-end products with authentication, a database and a deployed front end talking to your own API.
Game development portfolio projects — Real-time systems where the tick budget, the network model and the feel of the thing are the engineering.
All 30 briefs — the complete library, grouped by difficulty.

Beginner

Shared House Expense Splitter

Spaced-Repetition Flashcards

Intermediate

Workout Tracker (Mobile)

Other tracks

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