Backends & QPU Selection

How to choose a backend

QCOS supports simulators and real quantum hardware (QPUs). The choice depends on your workload size, budget, and accuracy requirements.

┌─────────────────────────────────────────────────────────────┐
│                    Backend Decision Tree                    │
│                                                             │
│  Qubits ≤ 32?                                               │
│   └─ YES → simulator_aer (free, fast, local)                │
│                                                             │
│  Qubits 25-40, need fast simulation?                        │
│   └─ YES → aws_braket_sv1 (pay per shot, up to 34 qubits)   │
│                                                             │
│  Need real QPU (noise, true randomness)?                    │
│   └─ YES → See QPU backends below                           │
│                                                             │
│  Not sure? Use Autopilot                                     │
│   └─ POST /api/v1/runtime/autopilot/plan                    │
└─────────────────────────────────────────────────────────────┘

List available backends

curl https://api.softquantus.com/api/v1/runtime/backends \
  -H "Authorization: Bearer sq-live-your-key"

Or list the supplier catalog:

curl "https://api.softquantus.com/api/v1/suppliers" \
  -H "Authorization: Bearer sq-live-your-key"

Simulators

Backend ID	Provider	Max Qubits	Cost	Notes
`simulator_aer`	QCOS (local)	32	Free tier	Ideal for dev & testing
`aws_braket_sv1`	AWS Braket	34	Per shot	State vector, exact simulation
`aws_braket_dm1`	AWS Braket	17	Per shot	Density matrix, noise models
`aws_braket_tn1`	AWS Braket	50	Per shot	Tensor network, specific topologies

Real QPU Hardware (Cloud)

AWS Braket QPUs

Backend ID	Device	Qubits	Technology	Typical Queue
`aws_braket_ionq_harmony`	IonQ Harmony	11	Ion trap	1–5 min
`aws_braket_ionq_aria1`	IonQ Aria 1	25	Ion trap	5–30 min
`aws_braket_ionq_aria2`	IonQ Aria 2	25	Ion trap	5–30 min
`aws_braket_ionq_forte1`	IonQ Forte 1	36	Ion trap	15–60 min
`aws_braket_rigetti_aspen_m3`	Rigetti Aspen-M3	79	Superconducting	5–30 min

Execute on an AWS Braket QPU through the runtime door (real-QPU jobs return an approval_token; approve via POST /api/v1/runtime/jobs/{job_id}/approve):

curl -X POST https://api.softquantus.com/api/v1/runtime/jobs \
  -H "Authorization: Bearer sq-live-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "qasm": "...",
    "backend_id": "aws_braket_ionq_aria1",
    "shots": 100
  }'

Estimate cost first:

curl -X POST https://api.softquantus.com/api/v1/runtime/estimate \
  -H "Authorization: Bearer sq-live-your-key" \
  -H "Content-Type: application/json" \
  -d '{"backend_id": "aws_braket_ionq_aria1", "shots": 100, "qubits": 10}'

Azure Quantum QPUs

Backend ID	Device	Provider	Qubits
`azure_ionq_simulator`	IonQ Simulator	IonQ	29
`azure_ionq_qpu`	IonQ QPU	IonQ	11
`azure_quantinuum_h1`	H1-1	Quantinuum	20
`azure_quantinuum_h2`	H2-1	Quantinuum	56
`azure_rigetti`	Ankaa-3	Rigetti	84

Execute on Azure Quantum through the runtime door:

curl -X POST https://api.softquantus.com/api/v1/runtime/jobs \
  -H "Authorization: Bearer sq-live-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "qasm": "...",
    "backend_id": "azure_ionq_qpu",
    "shots": 100
  }'

IBM Quantum QPUs

curl -X POST https://api.softquantus.com/api/v1/runtime/jobs \
  -H "Authorization: Bearer sq-live-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "qasm": "...",
    "backend_id": "ibm_brisbane",
    "shots": 1024
  }'

HPC Backends

Backend ID	Description	Use case
`lumi_cpu`	LUMI supercomputer (CSC Finland)	Heavy simulations via SSH/SLURM
`azure_cpu_worker`	Azure Container App CPU	Medium simulations, async

Circuit workloads target HPC-class simulators through the same runtime door (POST /api/v1/runtime/jobs with the HPC backend’s backend_id). Script-style HPC jobs use the HPC module:

curl -X POST https://api.softquantus.com/api/v1/hpc/jobs \
  -H "Authorization: Bearer sq-live-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "job_type": "simulation",
    "command": "python run_simulation.py",
    "resources": {"cpus": 16, "memory_gb": 64}
  }'

On-Premise QPU Connection

Connect your own quantum hardware to QCOS:

# Register your backend credentials
curl -X POST https://api.softquantus.com/api/v1/backends/credentials \
  -H "Authorization: Bearer sq-live-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "provider": "ibm_quantum",
    "name": "My Lab IBM QPU",
    "credentials": {
      "token": "YOUR_IBM_TOKEN",
      "instance": "ibm-q/open/main"
    }
  }'

Then execute using your credential:

curl -X POST https://api.softquantus.com/api/v1/backends/execute \
  -H "Authorization: Bearer sq-live-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "credential_id": "cred_xyz",
    "circuit": "...",
    "backend": "ibm_brisbane",
    "shots": 1024
  }'

Supported on-premise providers: ibm_quantum, ionq, rigetti, quantinuum, dwave, and custom backends.

Check backend health

curl https://api.softquantus.com/api/v1/providers/health \
  -H "Authorization: Bearer sq-live-your-key"

Cost comparison across backends

curl -X GET "https://api.softquantus.com/api/v1/roi/compare-providers?evaluations=100&shots_per_eval=1000" \
  -H "Authorization: Bearer sq-live-your-key"

Core

Modules

Certification

Backends & QPU Selection

Backends & QPU Selection

How to choose a backend

List available backends

Simulators

Real QPU Hardware (Cloud)

AWS Braket QPUs

Azure Quantum QPUs

IBM Quantum QPUs

HPC Backends

On-Premise QPU Connection

Check backend health

Cost comparison across backends

​Backends & QPU Selection

​How to choose a backend

​List available backends

​Simulators

​Real QPU Hardware (Cloud)

​AWS Braket QPUs

​Azure Quantum QPUs

​IBM Quantum QPUs

​HPC Backends

​On-Premise QPU Connection

​Check backend health

​Cost comparison across backends

Backends & QPU Selection

How to choose a backend

List available backends

Simulators

Real QPU Hardware (Cloud)

AWS Braket QPUs

Azure Quantum QPUs

IBM Quantum QPUs

HPC Backends

On-Premise QPU Connection

Check backend health

Cost comparison across backends