Use case · Web & apps
API backends
An API backend is the server-side infrastructure serving API requests to apps, mobile clients, and other services. It must respond with low latency, scale to handle many clients and requests, and stay reliable, since whatever calls it depends on it. Dedicated, EU-hosted infrastructure gives an API backend performance, control, and European data sovereignty.
Key points
- An API backend is the server-side that serves API requests to apps, clients, and other services.
- It must respond with low latency, since clients wait on its responses.
- It scales to handle many clients and requests, often by scaling horizontally.
- It must be reliable, because whatever calls the API depends on it.
- EU hosting keeps the data an API backend handles under European sovereignty.
What is an API backend, and what does it need?
An API backend is the server-side infrastructure that serves an application programming interface — responding to requests from the clients that use it, whether web front-ends, mobile apps, or other services. Modern applications are often built so that a backend exposes an API which various clients call to get data and perform actions, so the API backend is the server-side foundation those clients depend on. It must respond to API requests quickly, handle the volume of requests from its clients, stay reliable because the clients depend on it, and manage the data behind the API. These needs shape what an API backend's infrastructure must provide.
Because clients depend on the API backend, its performance and reliability determine much about the applications built on it. A slow API backend makes every client that calls it slow; an unavailable one makes the clients unable to function; so the backend's quality propagates to everything depending on it. Hosting an API backend well means providing infrastructure that serves requests quickly, scales to the request volume, stays reliable, and handles the data securely. This page focuses on API backends generally; related patterns such as microservices and SaaS backends are covered on their own pages, while what follows attends to what serving an API needs.
Performance and latency
An API backend must respond with low latency, because the clients calling it wait on its responses, and slow API responses make everything built on the API slow. When a client calls an API — a mobile app fetching data, a front-end loading a page, another service making a request — it waits for the response before it can proceed, so the latency of the API backend directly affects the responsiveness of the client. A fast API backend gives quick responses that keep clients responsive; a slow one drags on every client that depends on it, degrading the whole application.
Achieving low latency means infrastructure that processes API requests quickly — adequate compute to handle the request processing, a responsive database or data store behind the API, and caching where it helps. The API backend's own processing, and the data access behind it, both contribute to response latency, so both must be fast. Caching frequently-requested data can reduce latency by avoiding repeated work. We provision API backend infrastructure for low-latency responses — sufficient compute, a responsive data layer, and support for caching — so that the backend answers requests quickly, keeping the clients that depend on it responsive, because the API's latency is felt by everything that calls it.
Scalability: handling many clients and requests
An API backend often serves many clients making many requests, and it must scale to handle that request volume, growing as the number of clients and requests rises. A popular API backend can receive a large and growing volume of requests from its clients, and it must handle them without slowing or failing, which means the infrastructure must scale to the request load. Because API backends are frequently designed to be stateless — not holding client-specific state between requests on any particular server — they often scale horizontally well, by running the backend across multiple servers and distributing requests among them.
This horizontal scaling lets an API backend handle high request volumes by adding servers behind a load balancer that spreads requests across them. The stateless design common to API backends suits this, since any server can handle any request, so capacity grows with the number of servers, and the failure of one is handled by the others. We provide the multiple servers and load balancing an API backend uses to scale horizontally, so that it can handle the request volume of its clients and grow by adding capacity as that volume rises. Scaling the backend to its request load is central to it serving its clients well, and the stateless, horizontally-scalable design makes this practical.
Reliability: clients depend on the API
An API backend must be reliable, because whatever calls it depends on it, and its failure cascades into the failure of the clients and services that rely on the API. When applications are built on an API backend, that backend becomes a dependency of all of them, so its downtime disrupts every client — apps that cannot fetch data, front-ends that cannot load, services that cannot get what they need. This makes the reliability of an API backend important beyond itself, since it underpins the availability of everything built on it.
Achieving reliability rests on dependable infrastructure and, for backends that need it, resilience arrangements. Reliable hardware in a dependable datacenter provides the foundation; and running the backend across multiple servers, as horizontal scaling does, adds resilience, since the failure of one server need not take the API down when others can serve requests. The level of resilience should match how critical the API's availability is to what depends on it. We host API backends on reliable infrastructure, with the redundancy that running across multiple servers provides, so that the backend stays available — because an API backend's reliability underpins the availability of all the clients and services that depend on it.
The database behind the API
Most API backends have a database or data store behind them, holding the data the API serves and modifies, and this data layer is often central to the backend's performance and reliability. When a client calls the API, the backend frequently reads from or writes to its database to fulfil the request, so the database's responsiveness affects the API's latency, and its reliability affects the API's. Under a high volume of API requests, the database can become a bottleneck if it cannot keep up, much as it can for a busy website, making the data layer a key focus for a busy API backend.
Serving the database well means giving it adequate resources, reducing load through caching, and scaling it where needed. A well-resourced database with fast storage and enough memory serves the API's queries quickly; caching frequently-requested data reduces how often the database is hit; and the database can be scaled to handle more load as the API's request volume grows. Getting the data layer right is often central to a fast, reliable API backend. We provide well-resourced database infrastructure behind API backends, with the caching and scaling their request volume requires, so that the data layer serves the API's requests rather than becoming the bottleneck that limits the backend under load.
Security and sovereignty
An API backend is exposed to the clients that call it and often to the internet, and it handles the data behind the API, so its security matters — protecting the backend from misuse and the data it holds from exposure. APIs need to control who can call them and what they can do, through authentication and authorisation, and the backend must be secured against attacks and its data protected, since an exposed or compromised API backend risks the data and the systems behind it. Security for an API backend spans controlling access to the API and securing the backend and its data.
The infrastructure supports this security and the sovereignty of the data the API handles. Secure, isolated infrastructure with protection against attacks provides a foundation for the backend's security, which the application's own authentication and authorisation build on. And because the API backend handles data — often personal or sensitive data of the application's users — where it runs governs that data's jurisdiction. VV Internet Hosting is incorporated in the Netherlands, within the EU, so an API backend hosted with us runs under European jurisdiction and outside the direct reach of the US CLOUD Act, keeping the data it handles under European law. For backends handling European users' data, this European sovereignty is a real consideration alongside performance and reliability.
Where VV Internet Hosting fits — and where it does not
We host dedicated infrastructure for API backends: compute sized for low-latency request processing, multiple servers with load balancing for horizontal scaling, well-resourced databases with caching, protection against attacks, and reliable hosting — in EU datacenters under European jurisdiction. This suits API backends that need performance, scalability, reliability, and European data sovereignty on infrastructure the provider controls, whether serving apps, mobile clients, or other services. For that, we are a strong fit, and we will size the infrastructure to the API's request volume and data.
We are clear about our limits. We provide the dedicated infrastructure you run your API backend on; we do not build or operate the API backend itself, nor provide a managed application platform that runs it for you. The backend's code, its API, and its operation are yours; we provide the infrastructure foundation with the performance, scalability, reliability, and sovereignty an API backend needs. If you want a managed platform that runs your backend, that is a different kind of offering. We are the dedicated, sovereign infrastructure on which you run and control your API backend — suited to those who want performance, control, and European sovereignty. If that fits your backend, we can host it well.
Related use cases
See also
Questions
API backends, answered plainly
Common questions about hosting for API backends.
What is an API backend?
The server-side infrastructure that serves an application programming interface — responding to requests from clients like web front-ends, mobile apps, or other services. Modern applications are often built so a backend exposes an API that various clients call to get data and perform actions, making the API backend the server-side foundation those clients depend on.
Why does latency matter so much for an API backend?
Because the clients calling it wait on its responses before they can proceed — a mobile app fetching data, a front-end loading a page, another service making a request. So the backend's latency directly affects the responsiveness of every client that depends on it. A slow API backend drags on everything built on it, which is why low-latency responses matter.
How does an API backend scale?
Often horizontally. API backends are frequently designed to be stateless — not holding client-specific state on any particular server — so they scale well by running across multiple servers with a load balancer distributing requests. Any server can handle any request, so capacity grows with the number of servers, and the failure of one is handled by the others.
Planning API backends infrastructure?
We host dedicated, EU-sovereign infrastructure sized to your workload — and we will tell you plainly when something else fits better. Tell us what you're building.