Mid-level portfolio and interviews

Why it matters

Moving from junior to mid-level product designer is less about prettier screens and more about showing judgement: framing problems, working with constraints, collaborating with engineers and product managers, and connecting design to outcomes. Interviews test exactly these things, usually through a portfolio presentation and a design challenge (a whiteboard exercise or a take-home task). Preparing for both is a skill you can practise.

What a mid-level portfolio shows

A junior portfolio proves you know the process. A mid-level portfolio proves you can use it in messy, real situations. Aim for two or three strong case studies rather than eight thin ones, and make sure they show:

• Problem framing: how you understood and sometimes challenged the brief.
• Trade-offs: what you chose not to do, and why (time, technical limits, business needs).
• Collaboration: how you worked with engineers, PMs, researchers and stakeholders.
• Systems thinking: how your work used or improved a design system (tokens, components, specs).
• Craft and accessibility: polished, accessible detail where it matters.
• Outcomes: metrics or research results, with honest sample sizes (the HEART and post-launch lessons give you the language).
• Your role: what you did, clearly separated from the team's work.

The portfolio presentation

Many interview loops include a 30 to 45 minute presentation of one or two projects. A reliable structure for each project:

1. Context (1 to 2 minutes): product, users, your role, team, timeline.
2. Problem (2 minutes): what was wrong and how you knew.
3. Process and key decisions (8 to 12 minutes): two or three decisions, each with evidence, options considered, trade-offs and the result.
4. Outcome (2 minutes): what changed, with numbers if you have them.
5. Reflection (1 to 2 minutes): what you would do differently.

Rehearse out loud and time it. Leave time for questions; interviewers learn most from your answers to "why?" and "what would you do if...?".

The design challenge

In a live challenge you get a short prompt, such as "Design a way for library members to avoid late fees", and 45 to 60 minutes. Interviewers are watching how you think, not whether you produce a perfect design. A dependable structure:

1. Clarify (5 to 10 min). Ask questions before drawing. Who are the users? What is the business goal? What platform? Any constraints? What does success look like? If the interviewer says "you decide", state your assumptions out loud.
2. Users and problem (5 to 10 min). Pick a primary user and their key need. Write a problem statement. Mention how you would validate it with research in real life.
3. Explore (10 min). Sketch several approaches quickly and talk through the trade-offs.
4. Choose and detail (15 min). Pick one, sketch the key flow and two or three important screens, including at least one edge case (an error or empty state) and an accessibility consideration.
5. Measure (5 min). Say how you would know it worked: a primary metric and a guardrail.
6. Wrap up (5 min). Summarise the problem, the solution, risks and what you would test first.

Talk the whole time. Silence makes it impossible for interviewers to see your reasoning.

Worked example: the first five minutes

Prompt: "Design a feature to help housemates share chores."

Good clarifying questions: "Is this a new app or a feature in an existing house-sharing app? Mobile? Are we optimising for fairness, fewer arguments, or less effort to organise? Are there constraints, like no notifications? How would the business measure success?"

Stated assumptions: "I'll assume an existing mobile app, the primary user is the person who currently organises chores, and success means fewer chores missed. In real life I'd check this with five interviews before designing."

Then the problem statement: "House organisers need a fair rota that runs itself, because chasing people causes friction." The rest of the session builds on that.

Take-home challenges

Some companies set a take-home task instead. Ask how long it should take and stick to it. Present your process and reasoning, not just final screens. Be cautious about very large unpaid tasks; it is reasonable to ask how the work will be used.

Common mistakes

• Jumping straight to screens without clarifying the problem.
• Designing for everyone. Pick a primary user.
• One idea only. Show you explored alternatives.
• Ignoring edge cases and accessibility.
• No success measure.
• Saying "we" throughout so your own contribution is invisible.
• Overrunning the presentation time.

Quick recap

• A mid-level portfolio shows framing, trade-offs, collaboration, systems thinking, craft and outcomes, with your role clear.
• Present each project as context, problem, key decisions, outcome and reflection, and rehearse with a timer.
• In design challenges: clarify, define user and problem, explore, detail, measure and wrap up, thinking aloud throughout.

Try it

On the Do tab you will practise a timed design challenge and refine your answer.