Protobuf Support

APXY can decode Protocol Buffer (Protobuf) encoded request and response bodies when you provide the corresponding .proto schema files. This makes it possible to inspect gRPC and other Protobuf-based API traffic in human-readable form.

CLI

Register a schema


# From a file
apxy tools protobuf add-schema \
  --name "user-service" \
  --file ./protos/user.proto
 
# From inline content
apxy tools protobuf add-schema \
  --name "order-service" \
  --content 'syntax = "proto3"; message Order { string id = 1; int32 amount = 2; }'

Flag	Default	Description
`--name`	—	Schema name (required)
`--file`	—	Path to a `.proto` file (mutually exclusive with `--content`)
`--content`	—	Inline proto definition (mutually exclusive with `--file`)

List registered schemas


apxy tools protobuf list-schemas

Remove a schema


apxy tools protobuf remove-schema --id <schema-id>

Decode a traffic record

Decode the Protobuf body of a captured request or response:


# Decode the request body
apxy tools protobuf decode --id <record-id> --scope request
 
# Decode the response body
apxy tools protobuf decode --id <record-id> --scope response

Flag	Default	Description
`--id`	—	Traffic record ID (required)
`--scope`	`response`	`request` or `response`

Use Cases

Inspect gRPC traffic


apxy tools protobuf add-schema --name "my-service" --file ./proto/service.proto
# Capture some gRPC traffic, then:
apxy tools protobuf decode --id <record-id> --scope response

Debug mobile app APIs

Many mobile apps use Protobuf for compact payloads. Register the schema and decode traffic to see what’s being sent:


apxy tools protobuf add-schema --name "mobile-api" --file ./proto/mobile.proto
apxy tools protobuf decode --id <record-id> --scope request