REST vs. GraphQL APIs: A Practical Guide for Product Teams
Introduction
When a startup begins building its backend, the API decision is usually not given much thought.
The team is more product focused.
The screens.
The database
The authentication.
Date of launch.
Then the app grows.
Suddenly you have mobile apps, web apps, admin dashboards and third party integrations all communicating with the same backend.
And that’s where the API architecture starts to matter.
One question that frequently arises is:
REST vs GraphQL: Which One Should You Choose?
Strong feelings exist on both sides.
REST is the obvious choice, say some developers.
Others say that “GraphQL is the modern way to build APIs.
But for a product team this should not be a popularity contest.
The question to ask is this:
Which approach fits the product, team and data needs?
Lets Start With REST
REST is an architectural style used to build web APIs around resources .
Imagine you are building an ecommerce application.
You could have:
/products
/users
/orders
/categories
A call for :
GET /products
could return a list of products.
To a plea to:
GET /products/123
might return a specific product.
The concept is pretty simple.
You expose resources through predictable endpoints, using standard HTTP methods such as:
• GET
• POST
• PUT
• PATCH
• REMOVE
In many applications this is a big advantage.
Why REST Became So Popular
REST is simple to understand.
API's are easy for a new developer to look at and get what's happening.
For instance:
GET → data grab
POST → create something
PATCH → change something
DELETE → remove something Plus
you also have a mature ecosystem around:
• HTTP
• cash
• authentification
• surveillance
• testing
• API gateway
• documenetation
But REST Has a Problem
Which makes REST a very practical default .
Your mobile app home screen should:
• user name
• image of profile
• 5 product recommendations
• three recent orders
• account balances
In a traditional REST architecture, they may come from multiple endpoints.
Something like this:
/user
/Orders
/My-Account
/recommendations
The application may require multiple requests.
And here is where inefficiencies can happen.
The problem of over-fetching
An API endpoint responds with:
• identity
• email address
• telephone
• Street Address
• Profile picture
• date of birth
• prefs
• settings
But the mobile screen only requires:
name + profile pic
You are receiving data that you don't really need.
This is over-fetching.
The API is sending back more information than the client asked for.
It may not be a big problem for a small app.
At scale, however, unnecessary data can impact:
• bandwith
• mobile speed
• Response size
• complexity of the application
Under-Fetching Is the Opposite Problem
Now imagine the endpoint just returns you:
name + profile picture
But your screen needs too:
recent orders
Now you need a second ask.
Perhaps another one for suggestions.
Another for account info.
In the end, the client makes several API calls to get one screen built.
That’s under-fetching.
And that’s one of the problems GraphQL solves that.
So, What is GraphQL Anyway?
GraphQL is a query language for your API and a runtime to execute those queries with that API.
Now the client can request the fields it needs instead of hitting several fixed endpoints and getting pre-defined response structures.
Imagine the app wanting:
• user name
• profile picture
• last three orders
The client can describe that requirement in a GraphQL request.
The server then sends the shape of data requested.
The idea is a good one:
the client asks for the data it requires.
REST vs GraphQL in simple english
Think of REST as ordering from a static menu.
You're picking:
Burger
Fries
Drank.
Standardly, what’s in each item is determined by the restaurant.
GraphQL is more like:
“Get me these exact ingredients in this exact combination.”
Such flexibility can be very useful.
But it adds complexity, too.
GraphQL is not automatically better
This is where product teams need to be careful.
GraphQL does some things really well.
But to bring it into every project is not a good architectural decision by itself.
You should consider:
• team experience
• application difficulty
• buffering
• authorization
• performance of queries
• observing
• API governance
A flexible API can be difficult to control if not carefully designed.
API is a Contract of a Product
This is a good way to think about APIs.
Your frontend and backend are communicating via a contract.
The frontend states:
“I have to know this.”
The backend states:
“Here’s what I offer.
A good API contract should be:
• anticipated
• registered
• locked down
• versionable
• maintainable
Whether you are using REST or GraphQL, these principles are still important.
REST Makes Resource Boundaries Explicit
One reason teams still choose REST is that they find resource boundaries easy to understand.
You could have:
Products
Users
Orders
Payment
Bills (3-5)
Each resource can have own endpoints.
This can help simplify backend architecture reasoning.
For business applications with well-defined resource relationships, REST can be a very good fit.
GraphQL Makes Exploring Relationships Easier
Now imagine a product where information is highly interlinked.
User has:
• abonnements • invoices
• groups
• projects
• permissions
Every project has:
• work
• members
• comments
• files
The frontend may need different combinations of these relationships per screen.
This kind of data querying can be more flexible with GraphQL.
Instead of creating a new endpoint for every possible combination , the client can query the fields it needs .
GraphQL: A Blessing for Mobile Applications
A special constraint for mobile applications.
Bandwidth counts.
Users might be in:
• mobile phone networks
• bad connections
• Networks are unstable
• small data allowances
Sending unnecessary data is not recommended.
GraphQL’s ability to request specific fields can therefore be helpful for some mobile applications.
But again, this is not to say that GraphQL will automatically make a mobile app faster.
Poorly written queries can create their own performance issues.
REST Makes Caching Easier to Understand
One big advantage of REST is HTTP caching.
Traditional caching mechanisms work naturally because REST often uses predictable URLs and standard HTTP semantics.
For instance:
GET /products/123
can be cached potentially per HTTP rules .
GraphQL may require more intentional caching implementation since many different queries can be sent to the same endpoint.
That does not mean caching cannot be done.
It just shifts the problem.
GraphQL Allows Powerful Queries
But there is a downside to flexibility.
For example, a client might ask:
Orders → Products → Reviews → Recommendations
Each relationship has further relationships.
A badly written query can get expensive.
Now the backend has to handle a potentially deep request.
This is why in GraphQL implementations you often need controls around:
• depth of query
• complexity of the query
• Throttling
•pagination
• authorization or approval;
More governance, more flexibility.
REST Has Its Own Issues Too
REST is not perfect.
Big applications can:
• too many end points
• versioning problems
• duplicate response constructs
• inconsistent APIs
• multiple requests per screen
The answer is not to write REST off.
The answer is to build REST APIs correctly.
What about version management?
Imagine your API is currently returning:
name
Later you will need:
firstName
and
lastName
REST teams often use versioning strategies such as:
/api/v1
/api/v2
And there are other ways.
With GraphQL it is a different problem because the schema can evolve, adding fields and slowly deprecating old ones.
Again, neither approach negates API lifecycle management.
Authentication Does Not Depend on REST or GraphQL
People mistakenly believe that GraphQL somehow solves authentication.
It does not.
You still need to figure out:
Who's this dude?
and: "
And what do they see?
You could try:
• sessions
• JSON Web Tokens
• OAuth
• API Keys
• role access control
API technology doesn’t eliminate these security responsibilities.
GraphQL May Add Complexity to Authorization
For example, a query asks
customer > orders > payment details
Should all those fields be visible to any logged in user?
No, obviously not.
So GraphQL needs to do careful field level authorization where required.
You must ensure that users can only see information that they are permitted to view.
This is especially important for:
• fintech
• health care
• SaaS enterprise
• HR systems
• admin platforms
REST Is Frequently A Fine Default
If your product is fairly simple REST can provide you:
• simple architecture
• expected end points
• large toolsets
• easy debugging
• developer experience you know and love
For many startups, that’s just what they need.
Don't introduce GraphQL just because somebody said it's more modern.
When GraphQL Starts To Make More Sense
GraphQL gets interesting when:
• clients need different shapes of data
• you have many relationships in your data
• same backend for multiple frontend platforms
• mobile bandwidth is important
• More flexible querying for frontend teams
Think:
Admin
dashboard
Web
iOS
Android
All on the same backend.
They might need different fields.
GraphQL can minimize the need to build custom endpoints for every client.
How about team experience?
This is probably one of the most neglected factors.
A technology can be great and still be a bad fit for your team.
If your developers are familiar with REST and your application has simple data requirements, REST might enable the team to move faster.
When a team already has strong GraphQL experience and the application benefits from the flexibility of data querying, GraphQL is easier to justify.
Architecture should fit the people who are building it.
A Startup Example
Let’s say you’re building a simple appointment scheduling system.
The resources that form your core are:
• users
• medical doctors
• meetings
• Pago
The relationships are pretty straightforward.
REST might be all you need.
Now suppose you’re building a large collaboration platform.
A user may be a member of:
• institutions
• teams
• projects
• workspaces
Each has:
• members
• permissions.
• functions
• remarks
• alerts
Different screen combinations require different combinations of these relationships.
GraphQL could become more attractive.
Things were different.
So should the architectural choice.
Don’t Make API Decisions Too Late
The API is something a lot of start-ups think of as "developers are able to work that out later.”
That’s risky.
And your API becomes a dependency to be:
· front-end
· cellphone
· associates
· internal tools
· integrations.
Changing the contract is much harder once external clients have relied on it.
Design it a little bit before you implement it.
A Practical Decision Framework
Consider these questions:
1. How many clients will be consuming the API?
Only one web application?
Or web + Android + iOS + partners?
2. How complex are the relationships within the data?
Simple resources?
Or strongly-linked data?
3. Do clients require different fields?
If so, GraphQL can give you an edge.
4. How important is the traditional HTTP caching ?
If cache is in the heart, REST can be easier.
5. Does the team understand GraphQL?
If not, consider the cost of learning and operations.
6. What is the data sensitivity?
Design of authorization is critical for financial or sensitive systems regardless of API style.
You Can Also Use Both.
This is important.
You don't have to choose between REST and GraphQL for your architecture.
Some organizations use both methods.
Example:
REST
for public integration and simple services.
GraphQL
for a complex frontend application.
Or one part of the platform could use REST, another part GraphQL.
Requirements should drive architecture.
The Biggest Error
The biggest mistake is not using REST.
It’s not opting for GraphQL either.
The biggest mistake you can make is choosing a technology without knowing what problem it is meant to solve.
You don’t need an architecture diagram in a startup.
It requires an architecture which:
• Developers are able to continue
• users can depend on
• the business is able to
• may vary with product
Final Takeaway
Because it’s simple, predictable and supported by a huge ecosystem, REST remains a strong and practical choice for many products.
GraphQL is particularly useful when clients want to select data in a flexible way and the underlying data model is quite complex.
Neither is always better.
The best API for a startup is usually one that meets today’s actual requirements, without adding unnecessary complexity for tomorrow.
At KarmaKoders we help startups design backend architectures and APIs that fit their actual product needs, from simple REST APIs to more complex GraphQL based ones.
Building a web or mobile product and not sure how to design your API? We’ll build the backend around your product, not the other way around.