Nvidia Cuopt Server API Python

cuOpt Server — Deploy and client (Python/curl)

This skill covers starting the server and client examples (curl, Python). Server has no separate C API (clients can be any language).

Start server

# Development
python -m cuopt_server.cuopt_service --ip 0.0.0.0 --port 8000

# Docker
docker run --gpus all -d -p 8000:8000 -e CUOPT_SERVER_PORT=8000 \
  nvidia/cuopt:latest-cuda12.9-py3.13

Verify

curl http://localhost:8000/cuopt/health

Workflow

1. POST to /cuopt/request → get reqId
2. Poll /cuopt/solution/{reqId} until solution ready
3. Parse response

Python client (routing)

import requests, time
SERVER = "http://localhost:8000"
HEADERS = {"Content-Type": "application/json", "CLIENT-VERSION": "custom"}
payload = {
    "cost_matrix_data": {"data": {"0": [[0,10,15],[10,0,12],[15,12,0]]}},
    "travel_time_matrix_data": {"data": {"0": [[0,10,15],[10,0,12],[15,12,0]]}},
    "task_data": {"task_locations": [1, 2], "demand": [[10, 20]], "task_time_windows": [[0,100],[0,100]], "service_times": [5, 5]},
    "fleet_data": {"vehicle_locations": [[0, 0]], "capacities": [[50]], "vehicle_time_windows": [[0, 200]]},
    "solver_config": {"time_limit": 5}
}
r = requests.post(f"{SERVER}/cuopt/request", json=payload, headers=HEADERS)
req_id = r.json()["reqId"]
# Poll: GET /cuopt/solution/{req_id}

Terminology: REST vs Python API

Use travel_time_matrix_data (not transit_time_matrix_data). Capacities: [[50, 50]] not [[50], [50]].

Debugging (422 / payload)

Validation errors: Check field names against OpenAPI (/cuopt.yaml). Common mistakes: transit_time_matrix_data → travel_time_matrix_data; capacities per dimension [[50, 50]] not per vehicle [[50], [50]]. Capture reqId and response body for failed requests.

Runnable assets

Run from each asset directory (server must be running; scripts exit 0 if server unreachable). All use Python requests:

• assets/vrp_simple/ — Basic VRP (no time windows)
• assets/vrp_basic/ — VRP with time windows
• assets/pdp_basic/ — Pickup and delivery
• assets/lp_basic/ — LP via REST (CSR format)
• assets/milp_basic/ — MILP via REST

See assets/README.md for overview.

Escalate

For contribution or build-from-source, see the developer skill.