Why REST APIs Are Becoming Essential for Infrastructure Monitoring

Introduction

REST (Representational State Transfer) is an architectural style for designing distributed systems and web services. REST APIs enable applications and systems to communicate through standard HTTP methods such as GET, POST, PUT, and DELETE.

Today, REST APIs have become the de facto standard for exposing data and services across modern IT environments. While the terms REST API and RESTful API are often used interchangeably, RESTful APIs fully adhere to REST architectural constraints.

For infrastructure monitoring, REST APIs are no longer just management interfaces; they are becoming primary sources of telemetry. As infrastructure vendors increasingly adopt REST APIs to expose operational data, understanding how they work has become essential for modern monitoring and observability.

How Do REST APIs Work?

A client application sends an HTTP request to a server through a REST API to perform a specific operation, such as retrieving data, updating a resource, or deleting an object.

The server processes the request and returns an HTTP response containing:

• A status code indicating whether the operation succeeded (2xx) or failed (4xx or 5xx)
• Optional response headers
• A response body, typically formatted as JSON, XML, or HTML

JSON has become the preferred format because it is lightweight, human-readable, and easy for applications to process.

Why Vendors Are Moving to REST APIs

Modern infrastructure platforms generate increasingly complex telemetry that traditional monitoring protocols were not designed to expose.

REST APIs allow vendors to provide:

• Richer data models containing detailed performance, health, and configuration information
• Structured JSON responses that are easier for applications to process than MIBs and OIDs
• Modern authentication and authorization mechanisms
• Faster API evolution without protocol limitations
• Better alignment with cloud-native and web-based architectures

As a result, vendors such as Dell, NetApp, Pure Storage, NVIDIA, HPE, and Proxmox increasingly expose operational data through REST APIs.

This evolution is already visible across major infrastructure vendors. While traditional monitoring interfaces remain supported, vendors increasingly invest in REST APIs as their primary telemetry and management interface.

REST APIs vs SNMP

REST APIs are not replacing SNMP entirely. Rather, the two technologies complement one another. While SNMP remains highly efficient for polling network devices, REST APIs provide richer and more structured telemetry from modern infrastructure platforms.

The following comparison highlights their respective strengths:

To illustrate the differences between REST APIs and SNMP, let’s compare the capabilities of the three MetricsHub NetApp connectors: NetApp Filer (SNMP), NetApp Filer (REST), and NetApp Filer REST v2.

This example illustrates why many vendors are investing in REST APIs. While SNMP remains valuable for hardware and environmental monitoring, REST APIs often expose deeper inventory, configuration, and storage-specific telemetry.

Why REST Monitoring is More Complex Than It Looks

While REST APIs provide richer telemetry, they also introduce new monitoring challenges.

Unlike SNMP, where most information can be retrieved through a relatively consistent polling mechanism, each REST API implementation is unique. Endpoints, authentication methods, data models, pagination, and response formats vary significantly from one manufacturer to another.

A monitoring solution typically needs to:

• Authenticate with a login endpoint
• Retrieve and refresh session tokens or API tokens
• Discover available resources
• Query inventory endpoints
• Query performance and health endpoints
• Handle pagination and multiple API versions
• Extract metrics from JSON responses
• Normalize vendor-specific data
• Export standardized telemetry

Collecting telemetry through REST APIs therefore involves much more than sending a simple HTTP request.

How Does MetricsHub Leverage REST APIs?

MetricsHub relies on REST APIs to collect performance, capacity, health, and configuration data from a wide variety of infrastructure devices and platforms, including storage systems, virtualization platforms, server management interfaces, and AI infrastructure.

During the discovery phase, MetricsHub sends HTTP requests to identify the target system and determine which connector should be activated. By analyzing the HTTP response, MetricsHub can automatically recognize supported technologies and apply the appropriate monitoring logic.

Connector activation typically follows one of two approaches:

• For a simple GET request: The relevant connector is activated when an HTTP 200 status code is returned or the response body contains a predefined regular expression.
• For a GET request with headers: MetricsHub sends the required headers and evaluates the response body against expected patterns before activating the relevant connector.

For example, when discovering a NetApp storage system, MetricsHub identifies the platform and ONTAP version, automatically selects the appropriate REST connector, and begins collecting health, capacity, and performance metrics.

Simplifying REST-Based Monitoring with MetricsHub

Most monitoring platforms can send requests to REST endpoints. The real challenge lies in understanding hundreds of vendor-specific APIs, authentication methods, endpoint structures, and data models.

Instead of writing and maintaining custom scripts for every vendor API, MetricsHub provides a library of production-ready connectors that already understand vendor-specific authentication flows, discovery mechanisms, endpoint structures, and telemetry semantics.

By interacting directly with vendor APIs, MetricsHub can retrieve detailed telemetry that may not be available through traditional monitoring protocols such as SNMP. This approach enables deeper visibility into modern storage systems, servers, virtualization platforms, and AI infrastructure.

A single REST API response can expose dozens of performance and health metrics. For example, a storage controller might expose the following metrics through a REST API:

{
  "name": "Controller-A",
  "cpu_usage": 73,
  "read_iops": 15234,
  "write_iops": 8123,
  "latency_ms": 1.7
}

MetricsHub automatically extracts these values, normalizes them, and transforms them into standardized OpenTelemetry metrics.

This enables observability platforms such as Grafana, Datadog, Cisco Splunk, and BMC Helix to consume telemetry from different technologies through a consistent data model.

Conclusion

As infrastructure vendors continue to expand their REST APIs, monitoring platforms must be able to collect and standardize increasingly diverse telemetry sources.

While REST APIs provide access to richer operational data, they also introduce challenges related to authentication, discovery, endpoint navigation, API evolution, and data normalization.

MetricsHub addresses these challenges through its extensive connector library, automated discovery capabilities, and OpenTelemetry-native architecture. By abstracting vendor-specific implementations, MetricsHub enables organizations to take advantage of REST-based monitoring without having to master every API individually.

Explore the MetricsHub connector library to discover how REST-based integrations can extend visibility across storage, servers, virtualization, and AI infrastructure—without custom API scripting.

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