Google API Gateway supports REST → gRPC transcoding out of the box.
AWS API Gateway does NOT provide equivalent REST → gRPC transcoding out of the box.
On AWS, you must add a translation layer (Envoy or grpc-gateway) to achieve the same behavior.
That’s the core conclusion of the spike.
What “out of the box” really means (important)
Google Cloud API Gateway
GCP API Gateway:
- Accepts REST/JSON
- Reads proto descriptors
- Applies HTTP mapping rules
- Converts JSON → Protobuf
- Sends gRPC over HTTP/2
- Returns HTTP responses
👉 You do not deploy or manage a gateway service.
The transcoder is managed by Google.
That’s exactly what your Terraform is doing today:
- Upload proto descriptors
- Define
http_mapping_rules - Point to
grpcs://...a.run.app
No extra pods. No custom gateway.
AWS API Gateway
AWS API Gateway:
- Is primarily a REST / HTTP API gateway
- Can proxy HTTP and integrate with Lambda
- Can proxy gRPC in limited scenarios
- Does not read proto descriptors
- Does not transcode JSON → Protobuf
- Does not map REST paths to gRPC methods
👉 There is no native feature in AWS API Gateway equivalent to GCP’s gRPC transcoding.
So if a browser sends:
DELETE /v1/user
AWS API Gateway has no idea:
- which gRPC method to call
- how to encode the request
- how to produce Protobuf
What you must do in AWS instead
Because ALB and AWS API Gateway don’t do transcoding, you add one explicit translation layer:
REST client
↓
ALB or AWS API Gateway
↓
Envoy OR grpc-gateway ← this replaces GCP API Gateway’s transcoder
↓
gRPC service
Code language: JavaScript (javascript)Envoy / grpc-gateway:
- reads the proto
- converts REST → Protobuf
- sends a proper gRPC request
Why AWS designed it this way (context)
This is not a “missing feature” by accident.
- AWS tends to keep infrastructure layers simpler
- Advanced protocol translation is expected to live in:
- Envoy
- application gateways
- service mesh (App Mesh)
GCP chose to productize gRPC transcoding inside API Gateway.
Different philosophies.
One sentence you can safely say in the workshop
“In GCP, REST-to-gRPC transcoding is a managed feature of API Gateway.
In AWS, there is no equivalent managed feature, so we need to run a translator such as Envoy or grpc-gateway in front of our gRPC services.”
That statement is technically correct and defensible.
Practical recommendation (final)
- For AWS + EKS + ALB, the closest equivalent to GCP API Gateway is:
- Envoy with gRPC-JSON transcoder
- grpc-gateway is a valid alternative when you prefer code-generated gateways.