The original API Gateway offers dedicated instances and serverless instances. You can also use VPC integration instances and dedicated instance clusters to meet specific business requirements.
API Gateway instance types
An API Gateway instance is a set of resources used to access and process requests to your APIs. The following instance types are available:
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Dedicated instances (VPC): Dedicated instances (VPC) share the same technical specifications as shared instances (VPC). You can purchase a higher RPS specification for a higher SLA guarantee with dedicated resources, including inbound public IP addresses, inbound IP addresses in VPCs, outbound public bandwidth, and isolated server clusters.
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Serverless instance: Serverless instances, previously named shared instances, are upgraded from shared instances region by region. Existing workloads on shared instances are not affected. Serverless instances use the same billing method and prices as shared instances but provide higher scalability and performance, making them better suited for scenarios with fluctuating traffic that require timely, O&M-free scaling.
For more information, see Choose an instance type.
Change an instance specification
You can upgrade or downgrade the specifications of a dedicated instance in real time if it does not meet your business requirements.
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You can change specifications only for instances that are running.
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If you upgrade the specification of a subscription instance, you must pay the price difference between the existing specification and the new specification. If you downgrade the specification of a subscription instance, you will be refunded the price difference by using the original payment method. Redeemed vouchers are not returned.
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The new specification takes effect immediately after the specification change is complete.
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The specification change takes about 5 to 10 minutes to complete. During the specification change, APIs that are running on the instance can still be called.
For more information, see Change an instance specification.
VPC integration instances
VPC integration instances simplify communication between API Gateway and your VPC. They are suitable for the following scenarios:
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API Gateway needs to access multiple resources in the same VPC, such as Elastic Compute Service (ECS) instances and Server Load Balancer (SLB) instances, as backend services. Typical scenarios include microservices and service discovery, such as Nacos.
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Hybrid cloud network communication is required. A backend service accepts only the private IP addresses of Alibaba Cloud VPCs in requests forwarded by API Gateway instances. For more information, see the Scenario 3: Access a backend service deployed in an on-premises data center from an ECS instance deployed on Alibaba Cloud section of the "Centralized API management on a hybrid cloud" topic.
For more information, see VPC-integrated dedicated instance.
Dedicated instance clusters
You can cluster multiple dedicated instances of the same type and specification in the same region to combine their capabilities. If a single dedicated instance of the largest specification cannot meet your requirements, clustering allows you to exceed individual instance limits for heavy-load scenarios. For more information, see Dedicated instance clusters.