gRPC API (Reference)#

The CuOptRemoteService gRPC API is defined in Protocol Buffers under the cuopt.remote package. Source files in the repository:

cpp/src/grpc/cuopt_remote_service.proto — service and job/chunk/log RPCs
cpp/src/grpc/cuopt_remote.proto — LP/MIP problem, settings, and result messages

Most users do not call these RPCs directly:

Remote execution — Python, C (cuOptSolve), and cuopt_cli forward solves when CUOPT_REMOTE_HOST and CUOPT_REMOTE_PORT are set (Quick Start, Advanced Configuration).
Python async gRPC client — cuopt.grpc.linear_programming.Client (Python Async gRPC Client).

Custom clients call CuOptRemoteService over gRPC using these definitions. This page summarizes the service for custom integrators and debugging.

Service: `CuOptRemoteService`#

Asynchronous Jobs#

RPC	Purpose
`SubmitJob`	Submit an LP or MIP job in one message (within gRPC message size limits).
`CheckStatus`	Poll job status by `job_id`.
`GetResult`	Fetch a completed result (unary, when the payload fits one message).
`DeleteResult`	Cancel the job if it is still queued or running, then remove all server-side state for that `job_id`.
`CancelJob`	Cancel a queued or running job.
`WaitForCompletion`	Block until the job finishes (status only; use `GetResult` for the solution).

Chunked Upload (Large Problems)#

RPC	Purpose
`StartChunkedUpload`	Begin a session; send problem metadata and settings (arrays follow as chunks).
`SendArrayChunk`	Upload one slice of a numeric array field.
`FinishChunkedUpload`	Finalize the upload and return `job_id` (same as `SubmitJob`).

Chunked Download (Large Results)#

RPC	Purpose
`StartChunkedDownload`	Begin a download session; returns scalar result fields and array descriptors.
`GetResultChunk`	Fetch one chunk of a result array.
`FinishChunkedDownload`	End the download session and release server state.

Streaming and Callbacks#

RPC	Purpose
`StreamLogs`	Server-streaming solver log lines for a job.
`GetIncumbents`	MIP incumbent solutions since a given index (only if the job was submitted with `enable_incumbents`; otherwise the list is empty).

Messages and Constraints#

Problem types — Wire categories are LP/QP or MIP. QP is submitted as lp_request (SolveLPRequest) with quadratic fields on OptimizationProblem. Routing over this gRPC service is not available yet (planned; use REST for remote routing today).
Solver settings — Carried as PDLPSolverSettings or MIPSolverSettings inside the request or chunked header, aligned with the NVIDIA cuOpt solver options documentation.
Errors — Transport failures use gRPC status codes. Some outcomes use Status::OK with response fields: CheckStatus reports unknown jobs as job_status=NOT_FOUND; GetResult uses transport NOT_FOUND / UNAVAILABLE (not ready) and status=ERROR_SOLVE_FAILED for failed solves; DeleteResult / CancelJob report outcomes in the response. See cuopt_remote_service.proto.