GraphQL: introspection-driven
Point the studio at a GraphQL endpoint and it sends a real introspection query, with your authorization attached, to read the schema. From there you get schema-aware autocomplete for fields, arguments and types, and you run queries and mutations with variables. Because the studio knows the schema, it can tell you when a field you reference no longer exists.
gRPC: unary and streaming
Register a .proto file or load the service definition by reflection, then pick a method and send a request. Both unary calls and server-streaming calls are supported, so you can test a method that returns one response and a method that returns a stream of them. The request and response are shown as structured messages, not opaque bytes.
Assertions that survive a schema change
Beyond asserting on a value, you can assert on the shape of a response: the fields that must be present and their types. A shape assertion fails when a field disappears or changes type, which is exactly the change that slips past a test that only checks a status code. This is how a contract regression is caught in the pipeline rather than in production.
What is not covered here
This guide is about GraphQL and gRPC. Real-time messaging protocols are a separate matter, and we would rather be precise than broad: MQTT in the studio today validates a topic name but does not publish or subscribe, so treat it as topic validation, not live messaging. Do not read a claim about GraphQL or gRPC as a claim about MQTT, WebSocket or SSE.
Questions people ask about this
- Does gRPC support client streaming?
- Unary and server-streaming calls are supported and verified. If you need bidirectional or client-streaming, ask on a demo call and we will tell you plainly whether it is available rather than imply it.
- Where is the basic request flow?
- The API testing studio guide covers environments, the credential vault, request chaining and the mock server. This guide adds the GraphQL and gRPC depth on top of it.
Source: /documentation/graphql-and-grpc-testing, updated 2026-09-18. Answers are checked against the shipped product on that date.
Found something out of date? The people who build the module answer the contact form on the home page, and corrections to this guide are dated above. Tell us.