The Rise of the Open Gateway: OpenAPI Spec and CAMARA

Yilia Lin

Yilia Lin

December 8, 2025

Technology

For decades, the telecommunications industry and the software development world existed in parallel universes. Telcos operated on complex, proprietary protocols like Diameter, SS7, and GTP, while modern developers built the web on REST, JSON, and HTTP. The network was a "dumb pipe"—reliable, but opaque and impossible to program.

That era is ending. The rise of 5G has transformed the underlying infrastructure into cloud-native software, and with that shift comes the GSMA Open Gateway initiative and Project CAMARA.

We are witnessing a paradigm shift where the network itself is becoming a programmable platform. However, exposing the raw power of a 5G core to the public internet requires rigorous standardization and robust management. This is where the OpenAPI Specification (OAS) and high-performance API gateways converge.

What is Project CAMARA and the Open Gateway Initiative?

To understand the scope of this revolution, we must look at the two pillars driving it: the GSMA and the Linux Foundation.

In February 2023, the GSMA launched the Open Gateway initiative. The goal was ambitious but simple: create a federation of Application Programming Interfaces (APIs) that work universally across different mobile network operators. An app developer should be able to write code once to check a device's location or request higher bandwidth, regardless of whether the user is on Verizon, Vodafone, or Orange.

While the GSMA defined the strategy, the code lives in Project CAMARA.

CAMARA is an open-source project under the Linux Foundation. Its mandate is to define, develop, and test these APIs. It acts as an abstraction layer. Rather than a developer needing to understand the complexities of a 3GPP specification or how to query a Home Subscriber Server (HSS), CAMARA exposes these capabilities as clean, standardized REST APIs.

The "Service APIs" Landscape

CAMARA is currently standardizing access to critical network capabilities, including:

  • SIM Swap: Instantly verify if a SIM card has recently been swapped to prevent fraud during banking transactions.
  • Device Location: Verify the geolocated position of a device without relying on GPS (useful for geofencing compliance).
  • Quality on Demand (QoD): Allow an application (like cloud gaming or remote surgery) to request stable latency or guaranteed throughput for a specific session.

The Role of OpenAPI Specification (OAS) in Standardization

Standardization is the bedrock of the Open Gateway initiative. If Operator A uses XML and Operator B uses JSON, the concept of a "universal network API" fails.

This is why OpenAPI Specification (OAS) is the chosen lingua franca for Project CAMARA. Every CAMARA API (e.g., qod-api, sim-swap-api) is defined strictly using OAS (YAML/JSON).

Why OAS Matters here

  1. Contract-First Development: CAMARA ensures that the interface is defined before any implementation occurs. This prevents scope creep and ensures consistency across different Telco implementations.
  2. Tooling Ecosystem: Because CAMARA uses standard Swagger/OAS guarantees, developers can import these definitions directly into tools like Postman for testing, or use generators to create SDKs in Python, Java, or Go automatically.
  3. Validation: API gateways rely on OAS definitions to police traffic. By loading the CAMARA OAS file into an API gateway, the system can automatically validate incoming requests (checking standard schema, required headers, and data types) before they ever reach the sensitive telecom core.
graph TD
    A[CAMARA Working Group] -->|Defines| B(OpenAPI Spec - YAML)
    B -->|Imported by| C{API Gateway}
    B -->|Generated| D[Client SDKs]
    E[App Developer] -->|Uses| D
    D -->|Calls| C
    C -->|Validates and Proxies| F[Telco Network Core]

    style B fill:#f9f,stroke:#333
    style C fill:#bbf,stroke:#333,stroke-width:2px

Architectural Deep Dive: The API Gateway as the Enabler

The existence of a text file describing an API (the OAS) is not enough. You need an engine to serve it. In the CAMARA architecture, the API gateway acts as the crucial "Northbound Interface" (NBI) exposure point.

Directly exposing the Network Exposure Function (NEF) or 5G Core to the public internet is a security suicide mission. An API gateway, such as API7 Enterprise (based on Apache APISIX), sits between the external developers and the internal network functions.

1. Protocol Translation and Orchestration

Telco cores often speak legacy protocols or complex internal HTTP/2 dialects. The API gateway acts as the translator, presenting the clean CAMARA REST/JSON interface to the world while handling the complex routing to the network functions in the backend.

2. Identity and Security (CIBA & OAuth 2.0)

Network APIs deal with highly sensitive data (PII). Security is non-negotiable. CAMARA standards heavily utilize OAuth 2.0 and OIDC (OpenID Connect).

A specific requirement often seen in Telco APIs is CIBA (Client-Initiated Backchannel Authentication). Unlike a standard browser redirect login, CIBA allows a backend server to trigger an authentication request on the user's phone (e.g., a push notification saying "Allow Bank App to verify your location?").

Managing these complex auth flows in every single microservice is inefficient. High-performance gateways handle these token exchanges, validations, and consent checks at the edge, ensuring that only authorized traffic enters the core.

3. Traffic Management and Rate Limiting

5G signaling storms are a real threat. If a popular app malfunctions and spams the Quality on Demand API, it could theoretically degrade network performance for other users. The API gateway enforces strict rate limits (as defined in the Service Level Agreements). Using API7, operators can limit traffic based on complex criteria—such as per-developer, per-IP, or even per-Token—ensuring the stability of the critical infrastructure.

graph LR
    Dev[Developer App] -- HTTPS/Oauth2 --> Gateway[API7 / API Gateway]
    subgraph "Telco Premise"
    Gateway -- Rate Limiting --> Auth[Auth Server / OIDC]
    Gateway -- Authorized Req --> NEF[Network Exposure Function]
    NEF --> PCF[Policy Control Function]
    NEF --> AMF[Access Management]
    end

    style Gateway fill:#ff9,stroke:#333,stroke-width:4px

Real-World Implementation: Quality on Demand (QoD)

To illustrate how these pieces fit together, let us look at the Quality on Demand (QoD) API—one of the most commercially promising operational APIs in the CAMARA suite.

Scenario: A specialized remote assistance app requires a guaranteed stable connection for a video feed where an expert guides a field technician.

  1. Discovery: The app developer downloads the QoD OpenAPI Specification from the CAMARA repository to understand the contract.
  2. Request: The app initiates a request to the Operator's API gateway: POST /sessions. The body contains the user's IP and the desired QoS profile (e.g., QOS_L for low latency).
  3. Gateway Enforcement:
    • Validation: The gateway validates the JSON body against the OAS schema (Are the coordinates valid? Is the profile name correct?).
    • Auth: It verifies the developer's OAuth token.
    • Policy: It checks if this specific partner is allowed to request QOS_L (perhaps a paid tier).
  4. Network Action: The gateway forwards the request to the NEF/PCF. The 5G core dynamically reserves resource blocks for that specific user session.
  5. Result: The technician gets a glitch-free video feed, even in a congested area.

This entire flow happens in milliseconds, orchestrated by the gateway based on the rules defined in the OpenAPI Specification.

Conclusion: Preparing for the API-First Network

The convergence of 5G, Project CAMARA, and the OpenAPI Specification represents the most significant shift in telecom architecture in twenty years. We are moving from a world of rigid, hardware-defined constraints to flexible, software-defined potential.

For developers, this opens up capabilities that were previously impossible. For Telcos and aggregators, it represents a new revenue stream. But this potential relies heavily on infrastructure. The implementation of CAMARA APIs is not just a coding exercise; it is an API Management challenge.

Success in the Open Gateway era requires a platform that is:

  1. OAS-Native: Able to ingest and strictly enforce CAMARA definitions.
  2. High-Performance: Capable of handling minimal latency overhead, as adding significant delay defeats the purpose of "Quality on Demand."
  3. Secure: Robust enough to protect the critical network core from the open internet.
Tags:
OpenAPI