Developer’s Guide to 5G and Network APIs
If you’ve heard about 5G technology but aren’t quite sure what it is or why it matters to you as a developer, you’re not alone. This guide aims to demystify 5G and explain its significance for software development.
At its core 5G is about networks: connecting billions of devices to cloud-based applications. For the first time, these networks are exposed through programmable software, allowing you to leverage Network APIs in your applications. This article will break down the essential network technologies behind 5G, giving you the foundation to understand and utilize these new capabilities through Vonage's Network APIs.
Layered diagram showing how programmable mobile networks are built—from RAN and core layers up to developer-facing platforms, enabling advanced network control.
Let’s start with the basics. The “G” in 5G stands for “generation,” so 5G is the fifth generation of cellular network technology. As the world shifts toward heavier mobile network usage through smartphones, computers, and a multitude of connected devices, data consumption has skyrocketed. 5G has evolved to handle this massive rise in data demand.
New 5G technologies promise up to 10 times the efficiency of previous generations. Many of these improvements come from better spectrum efficiency and the ability to provide service over new frequency bands. But what does that mean? The answer lies in 5G New Radio (5G NR) technology.
5G New Radio (NR) is the global standard that encompasses both the physical layer and the software protocols enabling high-speed and low-latency communication over various frequency bands. But why are these different radio frequencies so important? To illustrate, let’s use a metaphor from economics.
In economics, specialization of labor means that as a workforce expands, each worker can focus on more specific tasks, leading to greater efficiency and expertise. This is why cities offer a wider variety of specialized products and services; each worker hones increasingly niche skills. Conversely, workers in rural areas might develop broader skill sets to handle a wider range of tasks.
Similarly, 5G NR unlocks a broader spectrum of frequencies than ever before. Just as an expanded workforce allows for specialization, the greater range of frequencies means that different frequencies excel at different functions. Higher frequencies can provide extremely high performance for heavy-capacity tasks like 4K streaming but don’t travel as far, making them less reliable over long distances. Lower frequencies travel further but may not offer the same data rates.
But frequency specialization is just one layer of 5G’s differentiated architecture. The real power of 5G lies in its ability to tailor not just the radio layer, but the entire network stack, from radio to core to orchestration, for specific use cases. This is made possible through network slicing.
A network slice is like a virtual private lane through the entire 5G infrastructure, configured with the exact characteristics needed for a particular type of application. One slice might be optimized for ultra-low latency (such as for autonomous vehicles), another for massive IoT deployments, and another for passengers streaming video on a high-speed train.
These slices are dynamically created and managed by systems in the Operations Support System (OSS) layer, which acts as the orchestration and automation brain of the network. If 5G NR provides the “specialized workers,” the OSS is the project manager assigning them to the right jobs based on context.
If you’re interested in the technical details of advanced antennas and how technologies like beamforming and Massive MIMO (multiple-input, multiple-output) contribute to low latency and high data performance, the Ericsson 5G site offers thorough explanations.
Diagram showing the trade-offs across 5G spectrum bands, comparing coverage, capacity, and latency from low to high frequency ranges.
As shown in the diagram above, 5G operates across a wider range of frequency bands than previous generations. These bands each have different physical properties that affect how far signals travel, how fast data can be transmitted, and how quickly the network can respond. While high bands can enable lower latency, it depends on how the network is configured, especially how it's scheduled and orchestrated. This is part of what makes 5G such a flexible and complex platform.
The specialization of frequencies doesn’t help much if we can’t effectively utilize them; it’s like having a team of specialists but no way to assign them tasks. Traditionally, telecom networks have been closed systems, inaccessible to external developers. 5G changes this paradigm by introducing programmable networks, opening up network capabilities through standardized Network APIs.
This transformation is made possible by key components like the Network Exposure Function (NEF) and the Application Function (AF), which act as bridges between the network and external applications (see below).
Diagram illustrating the interaction between 5G network functions and 5G applications via NEF and AF, showcasing authentication, policy control, and communication flow.
The NEF acts as a secure gateway between internal network services and the outside world. It enforces policies, authenticates requests, and ensures only authorized applications can interact with the network; similar to how an API gateway governs access to microservices in a cloud environment.
The AF lives in the control plane of the 5G core and orchestrates how apps interact with network services. It manages sessions, resources, and traffic prioritization behind the scenes to help ensure performance and reliability for things like video calls, streaming, or IoT device connectivity.
While NEF and AF make programmability possible, they are not developer-facing. That’s where the CAMARA Project comes in.
CAMARA is a global initiative, under the LINUX Foundation, to openly standardize developer-friendly Network APIs across operators, vendors, and countries. It abstracts the complexity of telecom infrastructure, making it simple to request capabilities like:
Verifying a user’s phone number without One Time Passwords (OTPs)
Requesting specific network performance (e.g., low latency)
Checking device connectivity or location
It’s similar to how cloud providers expose powerful infrastructure capabilities through clean APIs, so developers can build without needing to know how the servers are wired.
Vonage is one of the few software-first companies actively shaping CAMARA
To understand how these programmable networks became possible, it’s essential to look at the evolution of network architecture that supports them. Modern networks differ from previous generations in two main ways: they access much higher frequency bands, and the Radio Access Network (RAN) architecture has evolved to include support for cloud-realizations.
Diagram comparing LTE, C-RAN, and Cloud RAN architectures, highlighting the shift from decentralized to centralized and distributed radio access networks.
While mobile networks have always had centralized elements, 5G brings a new level of architectural flexibility. Instead of one-size-fits-all base stations, network functions are now modular and often virtualized. This allows mobile operators to tailor deployments based on performance, cost, and geography.
In mobile network technology, the RAN is the system that connects user devices, such as smartphones, computers, and IoT devices, to the core network via radio signals. While RAN can be complex, the key components we should focus on are:
Antennas: Transform between electrical signals and radio waves.
Radios: Convert between digital data and RF signals that can be transmitted wirelessly. They ensure signals are sent at the correct frequencies and power levels for clear communication.
Basebands: Process the signals between the core network and the user devices such it can be transmitted over the air.
Core Network: Connects signals between RAN and the internet and other communication services. It handles tasks like routing calls, managing data, and ensuring continuous connectivity as users move between different areas.
Just like virtual machines in cloud computing decouple software from hardware, modern networks can separate key network functions from the physical infrastructure. Separating the RAN functionality (network functions) from the functional realizations allows for on-demand provisioning and scaling separately for the Control Plane (CP) and User Plane (UP), the part of the network that manages connections and the part that carries the actual users’ data. This decoupling enables new capabilities like slicing, dynamic routing, quality-of-service control, and session management through APIs, much like how modern microservices let you configure different parts of your application architecture independently.
As the RAN architecture evolves, it’s important to note that networks are backward compatible. 5G was designed to be introduced smoothly over a prolonged period, ensuring continuity for existing devices and services. This is why many initial Network APIs are also available in 4G/LTE networks, like Sim Swap, Number Verification, and QoD. However, to unlock new use cases that only 5G can provide, like ultra-low latency and significantly higher capacity, standalone 5G will ultimately be required.
Understanding 5G’s architecture can be complex, but as software developers interested in Network APIs, it’s important to grasp some key concepts that make 5G networks programmable and flexible.
As mentioned earlier, the decoupling of the User Plane and the Control Plane is a fundamental advancement in 5G that impacts us as developers. But what exactly do these planes do?
Think of the Control Plane as the network’s “orchestrator.” It handles signaling and network management tasks necessary for establishing, maintaining, and terminating connections between user devices and the network. While it doesn’t carry user data directly, it supports and manages the operations of the User Plane.
The User Plane is responsible for the actual transmission of user data between the user’s device and the network, like internet traffic, video, and voice. It handles the payload that end users generate and consume, such as video streaming, web browsing, and file downloads.
In software terms, you can compare the Control Plane to the control logic in an application that manages workflows, while the User Plane is like the data processing layer that handles the actual data flow.
This separation allows for more flexibility and efficiency. For example, edge computing brings User Plane functionality closer to end-user devices, reducing latency by processing data near its source; much like caching frequently accessed data closer to the user in web applications.
Just as 5G specializes in frequencies, it also specializes in network functions. Understanding these key components helps us see how Network APIs interact with the network.
Important nodes to highlight:
User Plane Function (UPF): The UPF handles User Plane traffic. Its proximity to the end-user is crucial for increased performance, enabling low-latency data transmission.
Unified Data Management (UDM): The UDM manages subscriber data and ensures secure access to network services. It stores user subscription information and determines which network slices a user can access.
Policy Control Function (PCF): The PCF manages network policies and Quality of Service (QoS). For instance, in the Quality on Demand (QoD) API, the PCF handles QoD profiles, ensuring that applications receive the necessary network resources based on their requirements.
While the full 5G architecture includes many nodes, each Network API exposed to developers interacts with specific combinations of these nodes. This specialization allows for more targeted and efficient network services. Just look at the following NR Core diagram used at Ericsson to see how many specialized nodes exist!
Functional architecture diagram illustrating 2G/3G, 4G EPC, and 5G Core (5GC) network functions across RAN, core transport, and service domains, with interfaces to user-data, communication services, exposure, charging, and lawful-intercept domains.
Aren't you happy that you only need to deal with the APIs?🙃
To illustrate how these components work together, let’s look at the Quality on Demand (QoD) API:
Diagram illustrating the Mobile Core nodes that support the Quality on Demand (QoD) API, from core control functions like Authentication Server and Network Exposure to user-facing elements such as the User Plane, application, and data network.
Session Management Function (SMF): Manages sessions between user devices and the network, handling tasks like creating, updating, and deleting data sessions. It communicates with the UPF and PCF to ensure proper traffic routing, QoS, and session control, using cloud-native principles for scalability.
Access and Mobility Management Function (AMF): Handles Control Plane signaling related to device registration, connection, and mobility management. In the context of the QoD API, the AMF works with the SMF to manage the network’s response to application requests.
Unified Data Management (UDM): Stores critical user information, such as subscription details and QoS profiles, ensuring efficient service delivery. It interacts with components like the Authentication Server Function (AUSF) to verify user credentials.
Policy Control Function (PCF): Integrates with the SMF and AMF via RESTful APIs, allowing for real-time policy and charging control. It ensures that services like enhanced Mobile Broadband (eMBB) and Ultra-Reliable Low-Latency Communications (URLLC) are handled efficiently.
When an application requests a specific QoS level via the QoD API, the request flows through the Network Exposure Function (NEF) and Application Function (AF) to the PCF, which then enforces the appropriate policies across the network functions involved.
Each API may rely on a different combination of underlying nodes. The great thing is that you don’t need to know anything about the nodes to use the API!
So, what do all these new nodes and new frequencies really mean? They mean that you as a developer have the ability to extend your application into the network. Just as the frequencies and the nodes have become more specialized, so too can your applications. Can you think of use cases where reliability and performance are critical? With the new network capabilities, you can programmatically adapt your application to take advantage of information or capabilities from the network to enhance reliability, performance, and security.
With 5G technology, software developers have access to powerful APIs that opens new possibilities. One of the most practical benefits is the ability to offer granular Quality of Service (QoS) control, allowing you to ensure optimal performance for different types of applications via the QoD API mentioned before:
Field Service Management: Technicians working remotely can rely on low-latency, high-speed connections to receive real-time updates, video feeds, or augmented reality (AR) overlays.
Tele-surgery: Procedures in remote settings, like cruise ships or disaster zones, demand ultra-low latency and guaranteed reliability. 5G slicing ensures dedicated network resources, allowing surgeons to control robotic instruments in real time from afar.
Another significant application of Network APIs is in fraud prevention, particularly for combating SIM swap attacks and verifying mobile numbers.
SIM Swap Protection: You can implement real-time checks to the user’s SIM card activation, identifying suspicious behaviour. This provides a powerful layer of defense, especially in industries like banking, where mobile number verification is critical for authentication and account security.
Number Verification: Authenticate users silently and securely using the mobile data network without requiring OTPs. This API confirms that the SIM card in a device matches the expected phone number. It's especially useful for preventing spam account creation, ensuring reliable contact information, and enhancing app security with minimal user effort.
5G APIs enable a significantly improved customer experience through data like device location and status.
Device Location Services (Location Verification API & Location Retrieval API): APIs can pinpoint a device’s location with greater accuracy, enabling location-based services, optimized delivery tracking, or personalized offers.
Proactive Device Monitoring: Accessing device status data allows you to monitor device health, signal strength, or battery life proactively. This enables service providers to address potential issues before they impact the user, improving customer satisfaction by reducing service downtime and offering personalized services.
Consider a banking app that wants to strengthen its fraud prevention systems, especially for sensitive actions like money transfers, password resets, or adding new beneficiaries. Traditionally, fraud detection relies on password checks, one-time passcodes (OTPs), and device fingerprinting, methods that can be intercepted or spoofed.
By leveraging Network APIs, the bank can build a more secure, real-time fraud detection layer directly tied to the mobile network itself.
For example, when a user initiates a high-value transaction, the app can first use the SIM Swap API to check if the user’s SIM card has been recently changed—an indicator of potential account takeover. It can then silently verify that the phone number matches the current SIM using the Number Verification API, without sending any SMS or email OTPs that could be phished.
To further enhance security, the app could use the Device Location Verification API to confirm that the device is located within a trusted area (e.g., the customer’s home country or registered address) before approving the transaction.
By combining these APIs, the banking app can implement a seamless background security check that is faster, more accurate, and significantly harder for attackers to bypass; offering a level of protection that wasn’t possible before Network APIs opened up access to mobile network intelligence.
Flowchart showing how network APIs like number verification, SIM swap detection, and location verification help secure high-value banking transactions.
Was this article challenging? Did the array of acronyms and concepts feel overwhelming? That’s perfectly okay. The beauty of Vonage Network APIs is that you don’t need to master all the intricacies of 5G technology to start leveraging it in your applications.
Stay one step ahead of hackers and begin integrating 5G capabilities using our APIs like Sim Swap and Network Verification.
To accelerate your development process, we’ve created resources like the Network API Sandbox and the Virtual CSP. These tools provide a controlled environment to test and deploy your applications confidently.
As 5G technology continues to evolve, now is the perfect time to explore its potential. And if understanding 5G seems complex, just imagine what 6G will bring!
This article aimed to demystify 5G technology and highlight its significance for software developers. If you found it informative, and thought-provoking, or even if it left you with questions, we’d love to hear your feedback. Feel free to reach out on the Vonage Developer Community Slack.
Learn more about the latest Network API developments at Ericsson.
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Benjamin Aronov is a developer advocate at Vonage. He is a proven community builder with a background in Ruby on Rails. Benjamin enjoys the beaches of Tel Aviv which he calls home. His Tel Aviv base allows him to meet and learn from some of the world's best startup founders. Outside of tech, Benjamin loves traveling the world in search of the perfect pain au chocolat.