In the API ecosystem, API proxies are a common topic of conversation. And it makes sense: an API proxy opens the door to communication. It sits between an API and software applications, managing and controlling the interactions.
The ultimate goal of an API proxy is to make communications secure and fast. It’s a checkpoint to ensure the use of proper credentials and security protocols. It’s also a matter of monitoring activities to log errors, bottlenecks, and potential threats.
A snapshot of how API proxies work
When a proxy is enough and when you need more
API proxies are right-sized for some situations and wildly under-sized for others. Use this as a decision shortcut.
| Situation | Proxy is enough | You need a gateway or federated platform |
|---|---|---|
| Number of APIs to expose | 1 or 2 | 3 or more (especially mixed internal and external) |
| Audience | Internal team you can email | External partners, paying customers, or self-service developers |
| Auth complexity | API key is fine | OAuth 2.0, JWT, fine-grained scopes, federated identity |
| Traffic shape | Steady, predictable | Burst-prone, multi-tier, monetized with quotas |
| Number of backend gateways | One | Two or more (especially across different vendors) |
| Operational surface | Single team owns it | Platform team needs catalog, portal, analytics, policy authoring |
| Monetization required | No | Yes (metering, tiered pricing, contracts) |
If even two of those rows fall into the right-hand column, a proxy will create more work than it saves within the first year.
An API proxy works by sitting between an API client and the backend service, intercepting every request and response so basic security and routing can be enforced without changing the backend. The proxy terminates TLS, validates an API key or simple token, optionally rewrites the request path or headers, forwards the call to the backend, then returns the response (sometimes with minor shaping) to the client. The whole point is that the backend never needs to know the proxy exists, and the proxy never needs to know the backend logic.
When a client makes an API request, the API proxy intercepts the request. At this point, the API proxy performs a series of functions. These functions include security checks, managing incoming traffic, and transforming data formats and endpoints.
Once all these functions are complete, the API proxy forwards the request to the API’s backend. The API processes the request and sends a response back. Before responding to the client, the API proxy may perform additional logging, data transformation, or error handling. At this point, the client receives a response, and the API interaction is complete.
See also: understanding the difference between an API proxy vs. API gateway
The use of API proxies, for better and worse
API proxies are useful when you need to put basic security in front of a single backend quickly, without ripping out or rewriting the backend. They are a poor fit once you have more than two or three APIs to govern, because the proxy approach pushes every policy decision (auth, throttling, transformation) into either the proxy configuration or the backend code, and neither scales gracefully across teams. The same lightweight quality that makes a proxy fast to deploy is what makes it expensive to maintain at scale.
API proxies are a common approach to an API governance framework. Acting as gatekeepers, they often front every API or gateway to enforce standards.
With this approach, API providers can monitor their APIs through a centralized approach. They have greater visibility into performance metrics and issues, which provides better insights and faster troubleshooting. At the same time, providers can better manage traffic to optimize resource allocation and curb API abuse.
That said, API proxies are not without their flaws. An API proxy adds a layer of processing that can slow down API performance. It also introduces a single point of failure. Any API proxy issues or downtime can disrupt your API ecosystem.
Axway takes a different approach to API management
Why an agent-based architecture beats a proxy in the data path
The proxy-in-the-data-path approach (every API call routed through a central proxy) has three architectural problems that get worse with scale.
- Latency tax. Every hop adds milliseconds, and an additional intermediary doubles every request and response trip. For latency-sensitive APIs (payments, real-time bidding, fraud scoring) the proxy hop is the single biggest controllable contributor to p99 latency.
- Single point of failure. The proxy becomes the most important system in your architecture; if it goes down every API in front of it goes down with it. Even with active-active redundancy, the proxy capacity has to scale with the sum of every backend it fronts.
- Vendor lock-in. Once your traffic is shaped to the proxy is policy DSL, switching costs are massive. Multi-vendor or hybrid-cloud estates end up with parallel proxies that cannot share policies.
The agent-based approach (used by Amplify Fusion) instead places lightweight agents beside each existing gateway runtime: AWS API Gateway, Azure API Management, Apigee, Kong, MuleSoft, Axway Gateway, and others. The agent reports API definitions and metadata to a central control plane and applies policy back to its local gateway, so the control plane gets unified governance without ever sitting in the data path. The result is one place to discover and govern every API in your estate, with zero latency penalty and zero forced re-platforming.
Axway takes a different approach to API management by avoiding the proxy-in-the-data-path model entirely. Instead of forcing every API call through a central proxy (which adds latency, cost, and a single point of failure), Axway uses lightweight non-obtrusive agents that observe, secure, and govern APIs running on any gateway in your estate, from the side. The control plane gets full visibility and policy enforcement; the data plane keeps running at native speed on whatever gateway already owns it.
Some API management solution providers rely on proxies to enable federated API management. But at Axway, we take a different path.
Our API management solution is genuinely universal and non-obtrusive. Without needing facades or proxies, you have a flexible system that allows for automated API discovery, consumption, subscription, and onboarding.
Unlike the API proxy approach, Amplify Agents do not sit in the data path. Instead, they work with your API gateways, including Amazon, Azure, MuleSoft, Apigee, Istio, and Kong, as well as unmanaged APIs, eliminating the need for an additional proxy layer.
This method not only simplifies the system architecture but also avoids the increased costs, latency, and deployment time typically associated with proxy-based solutions.
By enabling straightforward API discovery, subscription, and observability, Amplify Agents offer a more efficient and streamlined approach to federated API management without the extra complications or overhead.
The insights you need without the challenges
When Axway surveyed API decision-makers to assess closing the gap between API development and API consumption, centralized tracking and management were cited as key factors driving API adoption.
API proxies may help meet those needs, but they can also hinder performance and introduce unnecessary points of failure. Axway simplifies things. Our approach to federated API management supports lower costs, improved efficiency, decreased risk, and streamlined operations.
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