API gateway in Azure API Management

This article provides information about the roles and features of the API Management gateway component and compares the gateways you can deploy.

Related information:

Role of the gateway

The API Management gateway (also called data plane or runtime) is the service component that's responsible for proxying API requests, applying policies, and collecting telemetry.

Specifically, the gateway:

Managed and self-hosted

API Management offers both managed and self-hosted gateways:

  • Managed - The managed gateway is the default gateway component that is deployed in Azure for every API Management instance in every service tier. With the managed gateway, all API traffic flows through Azure regardless of where backends implementing the APIs are hosted.

    Note

    Because of differences in the underlying service architecture, the Consumption tier gateway currently lacks some capabilities of the dedicated gateway. For details, see the section Feature comparison: Managed versus self-hosted gateways.

  • Self-hosted - The self-hosted gateway is an optional, containerized version of the default managed gateway. It's useful for hybrid and multi-cloud scenarios where there is a requirement to run the gateways off Azure in the same environments where API backends are hosted. The self-hosted gateway enables customers with hybrid IT infrastructure to manage APIs hosted on-premises and across clouds from a single API Management service in Azure.

    • The self-hosted gateway is packaged as a Linux-based Docker container and is commonly deployed to Kubernetes, including to Azure Kubernetes Service and Azure Arc-enabled Kubernetes.

    • Each self-hosted gateway is associated with a Gateway resource in a cloud-based API Management instance from which it receives configuration updates and communicates status.

Feature comparison: Managed versus self-hosted gateways

The following table compares features available in the managed gateway versus those in the self-hosted gateway. Differences are also shown between the managed gateway for dedicated service tiers (Developer, Basic, Standard, Premium) and for the Consumption tier.

Note

Infrastructure

Feature support Managed (Dedicated) Managed (Consumption) Self-hosted
Custom domains ✔️ ✔️ ✔️
Built-in cache ✔️
External Redis-compatible cache ✔️ ✔️ ✔️
Virtual network injection Developer, Premium ✔️1
Private endpoints ✔️ ✔️
Availability zones Premium ✔️1
Multi-region deployment Premium ✔️1
CA root certificates for certificate validation ✔️ ✔️2
Managed domain certificates ✔️ ✔️
TLS settings ✔️ ✔️ ✔️

1 Depends on how the gateway is deployed, but is the responsibility of the customer.
2 Requires configuration of local CA certificates.

Backend APIs

API Managed (Dedicated) Managed (Consumption) Self-hosted
OpenAPI specification ✔️ ✔️ ✔️
WSDL specification) ✔️ ✔️ ✔️
WADL specification ✔️ ✔️ ✔️
Logic App ✔️ ✔️ ✔️
App Service ✔️ ✔️ ✔️
Function App ✔️ ✔️ ✔️
Container App ✔️ ✔️ ✔️
Service Fabric Developer, Premium
Passthrough GraphQL ✔️ ✔️1
Synthetic GraphQL ✔️
Passthrough WebSocket ✔️

1 GraphQL subscriptions aren't supported in the Consumption tier.

Policies

Managed and self-hosted gateways support all available policies in policy definitions with the following exceptions.

Policy Managed (Dedicated) Managed (Consumption) Self-hosted
Dapr integration ✔️
Get authorization context ✔️
Quota and rate limit ✔️ ✔️1 ✔️2
Set GraphQL resolver ✔️

1 The rate limit by key and quota by key policies aren't available in the Consumption tier.
2 By default, rate limit counts in self-hosted gateways are per-gateway, per-node.

Monitoring

For details about monitoring options, see Observability in Azure API Management.

Feature Managed (Dedicated) Managed (Consumption) Self-hosted
API analytics ✔️
Application Insights ✔️ ✔️ ✔️
Logging through Event Hubs ✔️ ✔️ ✔️
Metrics in Azure Monitor ✔️ ✔️
OpenTelemetry Collector ✔️
Request logs in Azure Monitor ✔️ 1
Local metrics and logs ✔️
Request tracing ✔️ ✔️ ✔️

1 The self-hosted gateway currently doesn't send resource logs (diagnostic logs) to Azure Monitor. Optionally send metrics to Azure Monitor, or configure and persist logs locally where the self-hosted gateway is deployed.

Authentication and authorization

Feature Managed (Dedicated) Managed (Consumption) Self-hosted
Authorizations ✔️ ✔️

Gateway throughput and scaling

Important

Throughput is affected by the number and rate of concurrent client connections, the kind and number of configured policies, payload sizes, backend API performance, and other factors. Self-hosted gateway throughput is also dependent on the compute capacity (CPU and memory) of the host where it runs. Perform gateway load testing using anticipated production conditions to determine expected throughput accurately.

Managed gateway

For estimated maximum gateway throughput in the API Management service tiers, see API Management pricing.

Important

Throughput figures are presented for information only and must not be relied upon for capacity and budget planning. See API Management pricing for details.

  • Dedicated service tiers

    • Scale gateway capacity by adding and removing scale units, or upgrade the service tier. (Scaling not available in the Developer tier.)
    • In the Standard and Premium tiers, optionally configure Azure Monitor autoscale.
    • In the Premium tier, optionally add and distribute gateway capacity across multiple regions.
  • Consumption tier

    • API Management instances in the Consumption tier scale automatically based on the traffic.

Self-hosted gateway

Next steps