The Future of API Design: From Data Dumps to Great Experiences

♻️ Knowledge seeks community 🫶 #13

👋 Welcome back to Stef’s Dev Notes - where I share thoughts on building better products from the frontend side.

If you’ve ever heard the phrase “Can’t you just handle that on the frontend?”, you know the pain I’m about to describe. APIs that dump raw data onto the client might seem flexible, but they slow teams down, frustrate developers, and ultimately block user experience.

In this series, we’ll explore how to escape the data-dump trap and design APIs that truly empower frontend teams, from the initial vision to practical patterns, collaboration techniques, migration strategies, and avoiding common pitfalls.

Today, we’ll start by understanding why the problem exists and what the future of API design should look like.

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Why Data Dumps Are a Dead End

As applications grow more complex-think analytics dashboards, real-time updates, multi-device support, and AI-powered personalization - the gap between what an API provides and what the UI needs will only widen if we stick to old habits.

APIs that hand over giant datasets leave frontend teams with problems that shouldn’t be theirs to solve:

• Performance bottlenecks
  Fetching 50,000 records to calculate 30 metrics isn’t just wasteful-it creates multi-second load times and drains browser memory. Future users will expect sub-second performance everywhere.

• Maintainability risks
  Spreading business rules across frontend and backend guarantees drift. When product logic changes, some code gets updated in the backend, some in the frontend, and bugs slip through the cracks.

• Testing complexity
  UI engineers end up writing backend-style unit tests for revenue calculations, timezone conversions, and currency formats. That makes the frontend codebase heavier than it should be.

• Developer experience debt
  Instead of focusing on design, accessibility, and usability, frontend teams are forced into writing mini ETL pipelines in JavaScript.

In the short term, this approach feels like “moving faster.” But in the long term, it slows everyone down.

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The Future of API Design

So how do we escape the trap of data-dump APIs? By treating APIs as experience enablers, not data forwarders. Here’s what that looks like.

1. Start With the UI, Not the Schema

The future of API design begins with product conversations, not database queries. Teams that succeed ask:

• What information does the user need to complete this task?

• What shape of data will allow the frontend to deliver it with minimal transformation?

• How will this need evolve as the product grows?

APIs designed from user goals stay relevant longer than those designed from table structures.

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2. Build Purpose-Built Endpoints

From Messy Client Processing…

Before purpose-built APIs, frontend processing often looked like this:

Messy, slow, and hard to maintain.

…To Clean, Purpose-Built Endpoints

Tomorrow’s products won’t tolerate APIs that return everything and hope the client figures it out. Purpose-built endpoints serve clear, focused use cases.

Request example:

Response:

Frontend consumption becomes simple:

No manual aggregation. No complex transformations. Just clean, ready-to-use data.

This isn’t over-engineering - it’s future-proofing: designing endpoints around what the product needs today and tomorrow, not just what’s easiest to expose right now.

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3. Collaborate on Data Shapes Early

The best future-facing teams don’t wait until after the backend is implemented to validate data needs. They start by mocking API responses.

During design, ask questions like:

• Can users filter by date range?

• Do we need both UTC and local time?

• What’s the currency format that works across markets?

This collaborative approach prevents expensive rewrites later and ensures both frontend and backend engineers are solving the same problem.

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4. Put Logic Where It Belongs

The critical question is not who can do it faster? but where should this logic live for the best user experience?

• Revenue calculations? → Backend, for consistency.

• Aggregations across thousands of rows? → Backend, for performance.

• Filtering small lists in the UI? → Frontend, for responsiveness.

Future-ready teams don’t treat this as an ownership battle. They treat it as experience-driven architecture.

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The Questions That Shape Better APIs

Shifting your API design mindset starts with changing the questions you ask.

• Instead of: “What data do you have?”
  Ask: “What does the user need to see or do?”

• Instead of: “Can you work with this response format?”
  Ask: “What format makes your job easiest and reduces future risk?”

• Instead of: “Just calculate it on the frontend.”
  Ask: “Would moving this server-side improve performance and consistency?”

These small shifts add up to APIs that are durable, adaptable, and genuinely useful.

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The Payoff of Future-Oriented API Design

When APIs are built for experiences, not just for data movement, the benefits compound:

• Faster performance → Dashboards load in seconds, not tens of seconds.

• Consistency across the product → Business rules live in one place.

• Happier developers → Frontend teams focus on UI, not data wrangling.

• Flexibility for growth → Adding new features becomes about extending APIs, not rewriting them.

The real win? Products that feel effortless for users. APIs that are invisible because they just work.

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Looking Ahead

As products get more complex, the backend/frontend divide only matters less to users. What matters is whether the product is fast, reliable, and delightful.

The next time you’re tempted to say “just handle it on the frontend,” stop and ask:

• Will this scale?

• Will this create consistency?

• Will this make our product feel better to use?

The future of API design isn’t about exposing data. It’s about empowering developers, accelerating teams, and delighting users.

That’s what great APIs will always do.

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Closing

APIs are the invisible backbone of the modern products. When they’re designed with care, users never notice them - they just experience speed, clarity, and reliability. When they’re not, everyone feels the pain.

This article was just the beginning. In the upcoming posts, we’ll dive into:

• Designing APIs in practice: How to go from schema to experience.

• Collaboration playbooks: Aligning frontend and backend early and often.

• Migration strategies: Escaping legacy data-dump APIs without breaking products.

• Common pitfalls and fixes: What happens when purpose-built APIs go wrong.

And now …

💡 Over to you:

What’s the most painful (or best!) API design you’ve worked with?

Share your stories - I’ll collect lessons and patterns as the series unfolds.

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Articles from the ♻️ Knowledge seeks community 🫶 collection: https://stefsdevnotes.substack.com/t/knowledgeseekscommunity

Articles from the ✨ Frontend Shorts collection:

https://stefsdevnotes.substack.com/t/frontendshorts

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👋 Get in touch

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