grapesy: industrial strength [gRPC][grpc:website] library for Haskell

Haskell library providing gRPC client and server.

Interoperability matrix

The gRPC framework comes with a test suite that tests interoperability between implementations as well compliance to the gRPC specification. As the table below shows, grapesy passes all of these tests, apart from the Open Request Cost Aggregation (ORCA) tests, which is not yet supported by grapesy.

Legend and version information

Legend:

• ✅ passed
• ❌ failed
• ❔ not supported by the reference (or reference does not conform to the gRPC specification)
• 🚫 not supported by grapesy

We last tested against version v1.81.0 (released May 29, 2026).

grapesy server versus reference client

Test	Python	C++	Go	Java	grapesy
cancel_after_begin	✅	✅	✅	✅	✅
cancel_after_first_response	✅	✅	✅	✅	✅
client_compressed_streaming	❔	✅	❔	✅	✅
client_compressed_unary	❔	✅	❔	✅	✅
client_streaming	✅	✅	✅	✅	✅
custom_metadata	✅	✅	✅	✅	✅
empty_stream	✅	✅	✅	✅	✅
empty_unary	✅	✅	✅	✅	✅
large_unary	✅	✅	✅	✅	✅
orca_oob	🚫	🚫	🚫	🚫	🚫
orca_per_rpc	🚫	🚫	🚫	🚫	🚫
ping_pong	✅	✅	✅	✅	✅
server_compressed_streaming	❔	✅	❔	✅	✅
server_compressed_unary	❔	✅	❔	✅	✅
server_streaming	✅	✅	✅	✅	✅
special_status_message	✅	❔	✅	✅	✅
status_code_and_message	✅	✅	✅	✅	✅
timeout_on_sleeping_server	✅	✅	✅	✅	✅
unimplemented_method	✅	✅	✅	✅	✅
unimplemented_service	✅	✅	✅	✅	✅

grapesy client versus reference server

Test	Python	C++	Go	Java	grapesy
cancel_after_begin	✅	✅	✅	✅	✅
cancel_after_first_response	✅	✅	✅	✅	✅
client_compressed_streaming	❔	✅	❔	❔	✅
client_compressed_unary	❔	✅	❔	❔	✅
client_streaming	✅	✅	✅	✅	✅
custom_metadata	✅	✅	✅	✅	✅
empty_stream	✅	✅	✅	✅	✅
empty_unary	✅	✅	✅	✅	✅
large_unary	✅	✅	✅	✅	✅
orca_oob	🚫	🚫	🚫	🚫	🚫
orca_per_rpc	🚫	🚫	🚫	🚫	🚫
ping_pong	✅	✅	✅	✅	✅
server_compressed_streaming	❔	✅	❔	❔	✅
server_compressed_unary	❔	✅	❔	✅	✅
server_streaming	✅	✅	✅	✅	✅
special_status_message	✅	✅	✅	✅	✅
status_code_and_message	✅	✅	✅	✅	✅
timeout_on_sleeping_server	✅	✅	✅	❔	✅
unimplemented_method	✅	✅	✅	✅	✅
unimplemented_service	✅	✅	✅	✅	✅

Unsupported tests

There are additional tests that are not supported by grapesy, but since these are not supported by any of the reference implementations that we tested, we did not consider them any further. The full list is:

• cacheable_unary
• channel_soak
• compute_engine_channel_credentials
• compute_engine_creds
• concurrent_large_unary
• google_default_credentials
• jwt_token_creds
• long_lived_channel
• oauth2_auth_token
• per_rpc_creds
• rpc_soak

Memory profiles

Screenshots of the "Area Chart" display of the eventlog2html output for selected RPC communication patterns.

Many connections

Client opens many connections and does a single non-streaming RPC.

Client profile:

Server profile:

Many calls

Client opens a single connection and does many RPCs.

Client profile:

Server profile:

Many messages

Client opens a single connection and does a single RPC that sends many messages.

Client profile:

Server profile:

Benchmarks

Run type	Linux (RPCs/s)		OSX (RPCs/s)
	Grapesy	Java	Grapesy	Java
sequential protobuf	4654.500	7169.283	2919.783	1907.350
concurrent protobuf	3326.283	10908.650	5032.950	4571.750
sequential json	2371.233	2427.900	909.417	1574.817
concurrent json	3019.733	6143.567	1151.017	3563.867