How to Optimize API Calls for Faster Mobile Apps
- Anupam Singh
- Oct 29
- 12 min read
Mobile apps rely heavily on fast and efficient API calls to deliver a smooth user experience. Slow APIs lead to frustrated users, app abandonment, and poor retention rates. To ensure your app runs quickly and reliably across varying network conditions, focus on these key strategies:
Reduce Payload Size: Minimize data transfer by compressing responses (e.g., Gzip or Brotli), using pagination, and filtering unnecessary data.
Lower Latency: Upgrade to HTTP/2 for multiplexing and faster connections. Use CDNs to bring servers closer to users and reduce travel time.
Batch API Calls: Combine multiple requests into one to reduce round trips. Tools like GraphQL or composite endpoints help streamline this process.
Leverage Caching: Store frequently accessed data both locally (client-side) and server-side to cut down on repetitive requests.
Monitor and Improve Continuously: Track metrics like response time, error rates, and throughput. Use real-time monitoring tools and test changes in staging environments before deploying.
Platforms like Digia Studio simplify API performance optimization with low-code tools and instant UI updates, eliminating delays caused by app store approvals. These methods ensure your app remains fast, responsive, and user-friendly.
The Ultimate Guide to API Performance - Efficient Data Fetching
Reduce Payload Size and Data Transfer
The amount of data exchanged between your mobile app and server plays a big role in how fast your app loads and how smooth it feels to use. If your app sends or receives large payloads, it can eat up bandwidth and slow things down - especially on weaker networks. To tackle this, focus on sending only the data that's absolutely necessary. Then, take it a step further by compressing responses and using smarter data retrieval methods like pagination and filtering.
Compress API Responses
Compression can work wonders for shrinking API responses without changing the actual data. A popular option is Gzip compression, which is widely supported and can noticeably cut down the size of text-based responses, speeding up load times. If you're looking for even smaller payloads, Brotli compression might be an even better choice.
To implement this, configure your API gateway to compress responses that exceed a certain size - say, anything over 1 KB. Keep in mind that compression is most effective for text-based formats like JSON or XML. Binary files, such as images or videos, or data that's already compressed won't see much benefit - and might even slow things down due to added overhead.
Beyond compression, you can further reduce data transfer by adopting pagination and filtering.
Add Pagination and Filtering
Large datasets can bog down your app if they're downloaded all at once. Pagination fixes this by breaking data into smaller, manageable chunks. This not only improves load times but also reduces memory usage. For example, cursor-based pagination works well for real-time data feeds, while offset-based pagination is a good fit for static datasets.
Filtering takes it a step further by letting your app request only the data it actually needs. Instead of pulling an entire dataset and sorting through it on the client side, design your API to handle filtering on the server side. For instance, you could allow filters based on date ranges, categories, or search terms to minimize the amount of data sent.
You can also combine multiple filters in one request. Imagine an e-commerce app where users can filter products by category, price range, and availability - all at once. Additionally, consider implementing field selection so clients can request just the data they need. For example, a product list view might only need names, prices, and thumbnails, while a detailed product page might require more in-depth information. This selective approach can dramatically slim down payload sizes and improve performance.
Cut API Call Latency and Round-Trip Times
Once you've minimized data size, the next step is to focus on cutting down travel time. Even the smallest payloads can feel sluggish if network travel times are high. Network latency - the time it takes for a request to make a round trip - has a direct impact on how responsive your app feels. To tackle this, you can upgrade connection protocols, position your servers strategically, and make your API calls more efficient.
Use HTTP/2 Protocol
Switching to HTTP/2 can bring a noticeable boost in performance compared to the older HTTP/1.1 protocol still used by many apps. One standout feature of HTTP/2 is multiplexing, which allows multiple requests to be sent simultaneously over a single connection. In contrast, HTTP/1.1 often processes requests one at a time, creating potential bottlenecks. HTTP/2 eliminates this limitation, making your app faster and more responsive.
Another advantage of HTTP/2 is its use of HPACK compression for headers, which reduces overhead. This is particularly useful for apps that send frequent API calls with similar headers.
Additionally, HTTP/2 supports server push, a feature where the server can send resources to the client proactively, even before they're requested. For instance, when a user opens their profile page, the server could preemptively send related data, such as recent activity or notifications, cutting down on the number of round trips needed.
Enabling HTTP/2 is often straightforward. On modern platforms, it's just a matter of configuration. If you're using cloud services like AWS or Google Cloud, their load balancers and API gateways typically support HTTP/2 out of the box.
While upgrading protocols is crucial, reducing physical distance with CDNs can further lower latency.
Deploy CDNs for Faster Access
Content Delivery Networks (CDNs) are a powerful way to reduce latency by placing API endpoints closer to your users. Instead of routing every request to your main server, CDNs direct traffic to the nearest edge location, cutting down on travel time.
To maximize the benefits, choose a CDN provider with strong coverage in regions where your users are concentrated. For example, if your app primarily serves users in the U.S., ensure robust coverage in cities like New York, Los Angeles, Chicago, and Dallas. For a global audience, use your user analytics to prioritize regions.
CDNs are particularly effective at caching API responses that don’t change often, such as user profiles, product catalogs, or app configuration data. Use cache headers like to specify how long data should remain valid, ensuring a balance between freshness and performance.
For dynamic content that can’t be cached, consider implementing geographic routing. Even if the data must be fetched in real time, routing requests to the nearest server can still significantly reduce latency.
After addressing protocols and geolocation, you can further streamline performance by consolidating API calls.
Batch Multiple API Calls
Reducing round trips by combining multiple API requests into a single call can make a big difference. For example, instead of sending separate requests for user data, notifications, and app settings, you could create a batch endpoint that delivers all this information in one response.
GraphQL is an excellent tool for this purpose. Unlike REST APIs, which often require separate endpoints for different data types, GraphQL allows clients to request everything they need in a single query. This eliminates the need for multiple round trips and simplifies data retrieval.
For REST APIs, you can achieve similar results with composite endpoints. For example, you could design a endpoint that aggregates data from various services and sends it as a single response. This is particularly useful for mobile apps or dashboards that rely on multiple data sources.
When designing batch endpoints, make sure they can handle partial failures gracefully. For instance, if one piece of data fails to load, the endpoint should still return the rest of the requested information while flagging the error. This approach minimizes delays and ensures users get as much data as possible without unnecessary interruptions.
Improve Performance with Caching and Data Storage
Cut down on API calls by caching frequently accessed data locally. This ensures faster responses, even when there's no network connection. While optimizing network calls is crucial, caching and local storage take it a step further by reducing delays and keeping essential data close at hand. Together, these strategies reduce reliance on network connectivity and improve overall app performance.
Set Up Client-Side and Server-Side Caching
Effective caching involves both client-side and server-side solutions. For client-side caching, iOS developers can use NSCache or Core Data, while Android developers can rely on Room or SharedPreferences. Be sure to set appropriate cache expiration times based on how often the data changes. For instance, HTTP headers like can guide the app on how long cached data should be considered fresh, striking a balance between reducing API calls and avoiding stale information.
Server-side caching is ideal for data that's computationally intensive to generate but doesn't change often - think product catalogs or aggregated statistics. Use tools like Redis or Memcached to store this data. A layered caching approach works best: check the client-side cache first, then the server-side cache, and finally make a fresh API call if needed.
Store Data Locally for Offline Access
Local data storage ensures your app remains functional even when users lose connectivity. For structured, searchable data, SQLite is a great choice. For simpler needs, key-value storage systems work well. This approach allows core app features to operate smoothly offline.
To maintain data accuracy, implement conflict resolution strategies such as last-write-wins. And always prioritize security: never store sensitive information like passwords or API keys in plain text. Use platform-specific encryption tools to protect stored data, and set up expiration policies to automatically clear outdated cached information.
Implement Rate-Limiting and Resource Management
Rate-limiting is essential to protect your API from being overwhelmed by excessive requests while ensuring fair resource usage. On the client side, throttle requests to prevent the app from flooding the server - this is especially important during rapid user actions or background syncs.
Define limits that align with your API's capacity and user requirements. For example, you might restrict profile updates to one per minute or limit the frequency of search queries to avoid misuse. Use exponential backoff strategies for retries when requests fail, spacing out retries progressively to prevent further strain on servers during outages.
Keep an eye on resource usage trends to spot areas for improvement. Monitor memory consumption from cached data and regularly clean up unused or outdated items to prevent storage from becoming bloated. This ensures your app stays efficient and responsive over time.
Monitor and Continuously Improve Performance
Once you've optimized payloads and reduced latency, the next step is to keep an eye on performance over time. Continuous monitoring is crucial because apps and user behaviors evolve, and without proper tracking, unnoticed issues can disrupt the user experience. By adopting a structured approach to monitoring, you can identify problems early and make informed updates to keep your app running smoothly. Start by focusing on the metrics that matter most.
Track Key API Metrics
Some key metrics to monitor include response time, error rates, and throughput. Response time measures how long it takes for a request to get a response, while error rates show how often requests fail. You should also pay attention to data transfer sizes and caching efficiency - both of which impact performance. For mobile apps, consider how API usage affects device resources like memory and battery life. Setting up alerts for any unusual spikes or drops in these metrics can help you react quickly before minor issues turn into major problems. These metrics form the backbone of effective monitoring.
Use Real-Time Monitoring Tools
Real-time monitoring tools are invaluable for keeping tabs on API performance. They can aggregate logs, link performance data to user actions or system events, and help your team pinpoint the root cause of issues. Dashboards displaying your key metrics allow you to track trends and spot performance dips as they happen. Automated reporting is another useful feature, helping you detect gradual changes over time. With these tools, you can confidently make adjustments while ensuring your app remains stable.
Test Changes in Staging Environments
Before pushing any performance updates to production, test them in a staging environment that closely mirrors your live setup. Use load tests and controlled experiments to simulate real-world conditions and measure the impact of your changes. Comparing metrics before and after implementation helps you gauge whether the updates are effective. Always have a rollback plan in place so you can quickly undo changes if something goes wrong, minimizing disruptions for your users. This step ensures your improvements are both safe and effective.
How Digia Helps with API Performance
When it comes to API performance, Digia goes beyond standard tweaks by offering tools that simplify and accelerate improvements. In today’s fast-paced mobile app development world, having adaptive solutions is no longer optional. Digia Studio tackles API performance challenges head-on with its server-driven UI platform, enabling developers to make real-time updates without waiting for app store approvals.
Update UI Instantly Without App Store Delays
One of the biggest hurdles in optimizing API performance is dealing with UI changes. For traditional mobile apps, even minor adjustments often mean rebuilding the app, submitting it to app stores, and waiting for approval - a process that can drag on for days or even weeks. Digia Studio eliminates this bottleneck with its server-driven approach.
"Design, update, and release mobile app experiences from one dashboard - no rebuilds, no approvals, 100% user adoption on day 1."
With this platform, developers can instantly tweak UI elements to adapt to varying API conditions. Whether it’s updating loading states, adding progress indicators, or incorporating fallback content, these changes can be made without touching the app’s codebase. The streamlined Design → Preview → Release → Live workflow ensures that updates are immediately available to all users.
Another advantage of this server-driven architecture is its ability to reduce the need for constant API calls to update the UI. This not only simplifies backend operations but also improves overall system efficiency.
Manage APIs with Low-Code Tools
Optimizing API performance often requires fast iterations, but traditional development processes can be slow and cumbersome. Digia Studio simplifies this with its visual builder, which features an intuitive drag-and-drop interface for API management.
"Customise Everything... customizing components, tokens, and APIs to fit any mobile app workflow."
This setup allows developers to fine-tune components and APIs directly within the studio, enabling improvements like request batching, payload filtering, or response caching - all without heavy coding. The low-code approach is particularly beneficial for A/B testing different API configurations. Instead of deploying multiple app versions to test strategies, developers can create distinct UI flows within Digia Studio and monitor their impact on API performance in real time. This approach makes it easier to scale and optimize performance for enterprise-level applications.
Scale with Enterprise-Grade Infrastructure
For apps handling high volumes of traffic, scaling without compromising performance is critical. Digia provides the infrastructure needed to support such demands, ensuring that API round-trip times remain low and performance remains steady as your user base expands.
"Enterprise-Grade, Built for Scale... performance infrastructure built for high-traffic apps."
Digia also prioritizes security and reliability. The platform is ISO 27001 compliant and features role-based access control to ensure data protection. With secure Git integration, development teams can version control their API configurations alongside UI updates. This makes it easy to track which optimizations work best and quickly roll back changes if necessary. It’s an infrastructure designed to grow with your app while keeping performance and security at the forefront.
Key Steps for Faster Mobile Apps
Improving API performance for mobile apps requires tackling common bottlenecks with a focused, step-by-step approach. Start by cutting down on data transfer. Use more efficient data formats like JSON and apply compression techniques such as Gzip. These adjustments can shrink payload sizes, which is especially helpful for users on slower networks.
Next, leverage HTTP/2 for multiplexing, deploy CDNs (Content Delivery Networks) to reduce latency, and batch API calls to limit the number of round trips. This is particularly important for mobile apps, which often make frequent, smaller requests that can add up.
Caching is another essential tool. On the client side, cache frequently accessed data locally to avoid unnecessary requests. On the server side, cache common queries to handle repetitive backend demands. Combining these strategies creates a multi-layered defense against sluggish API performance.
Monitoring is critical. Keep an eye on metrics like response times, error rates, and throughput. Testing changes in a staging environment before rolling them out ensures smoother performance and helps spot potential issues early. This proactive approach allows for faster iteration and keeps the app's UI responsive with real-time updates.
Modern platforms like Digia Studio take optimization a step further by enabling instant updates without requiring app store approvals. This server-driven model eliminates the delays of traditional workflows, where even minor changes to the UI might require weeks of development and app store review.
"Build and Ship Mobile Apps WITHOUT App Store Release"
With platforms like Digia, you can tweak loading states, progress indicators, and fallback content immediately based on API performance data. Plus, their enterprise-grade infrastructure scales automatically to handle increased traffic, and low-code tools simplify the optimization process.
The real game-changer here is the speed of iteration. Traditional workflows can take weeks to implement and test changes, but server-driven platforms cut this down to hours - or even minutes. This allows for rapid A/B testing of performance strategies and provides the flexibility to roll back changes instantly if needed.
FAQs
How can switching to HTTP/2 boost the performance of mobile apps?
Switching to HTTP/2 can make a noticeable difference in how mobile apps perform, especially when it comes to reducing delays and transferring data more efficiently. Unlike HTTP/1.1, HTTP/2 supports sending multiple requests at the same time over a single connection. This eliminates the need to create multiple connections, cutting down on the extra work and delays that come with setting them up.
On top of that, HTTP/2 includes smart features like header compression and server push. These tools help speed up the communication between the app and the server, leading to quicker load times, smoother interactions, and less data consumption. This is a big win for mobile apps, particularly in areas where bandwidth is limited or connection speeds are slower.
How does using a server-driven UI platform like Digia enhance API performance?
A server-driven UI platform such as Digia boosts API performance by allowing instant updates and adjustments without waiting for app store approvals. This means developers can swiftly tackle performance challenges, apply changes, and cut down on latency as it happens.
Digia's drag-and-drop widgets and server-driven architecture streamline the process, enabling quicker iterations and updates. This makes it easier to refine API interactions and enhance the overall responsiveness of apps.
How does caching on both the client-side and server-side improve mobile app performance?
Caching plays a crucial role in boosting mobile app performance by cutting down on delays and reducing the need for constant API calls. Client-side caching saves frequently used data directly on the user’s device. This means the app can quickly load content without waiting for a response from the server. Meanwhile, server-side caching works by storing pre-processed or commonly requested data on the server, ensuring faster responses for multiple users accessing similar content.
When these two caching methods are used together, apps become more responsive, smoother to use, and consume less data. Plus, they lighten the load on servers. This approach is especially valuable for apps with heavy traffic or for users in areas with slower internet speeds.
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