Transpile using REST API

The process of rewriting a given input circuit to match the topology of a specific quantum device, and optimizing the circuit instructions for execution on noisy quantum QPUs, is known as transpilation.

You have two transpilation options:

• Transpile locally via Qiskit before generating the QASM string.

• Use the Qiskit Transpiler Service API.

The steps in this topic describe how to transpile a given QASM circuit and obtain results using the Cloud Transpiler REST API, and include suggestions on how to submit the transpiled quantum circuit to IBM compute resources. For an example that uses parameterized input, see Sampler primitive with REST API and parameterized circuits.

Query the Qiskit Transpiler Service

Query the Qiskit Transpiler Service API and provide your QASM string as input. See more details in the API reference documentation.

There are two ways to invoke the Qiskit Transpiler Service using REST API: with regular transpilation, and with AI-enhanced transpilation. The following demonstrates both ways to invoke the Qiskit Transpiler Service API.

backend='ibm_brisbane' #choose your IBM Backend
 
headers = {
"accept": "application/json",
"Authorization": f"Bearer {token}",
"Content-Type": "application/json",
}
body= {
"qasm_circuits": qasm_string,
}
params = {
"backend": backend,
"optimization_level": 1,
"ai": "false", # "true", "false" and "auto"
}
 
resp = requests.post(
    "https://cloud-transpiler.quantum.ibm.com/transpile",
    headers=headers,
    json=body,
    params=params,
)

backend='ibm_brisbane' #choose your IBM Backend
 
headers = {
"accept": "application/json",
"Authorization": f"Bearer {token}",
"Content-Type": "application/json",
}
body= {
"qasm_circuits": qasm_string,
}
params = {
"backend": backend,
"optimization_level": 1,
"ai": "true", # "true", "false" and "auto"
"coupling_map": [],
"qiskit_transpile_options": [],
"ai_layout_mode": 'OPTIMIZE', # 'KEEP', 'OPTIMIZE', 'IMPROVE'
}
 
resp = requests.post(
    "https://cloud-transpiler.quantum.ibm.com/transpile",
    headers=headers,
    json=body,
    params=params,
)

Request results based on the task_id

Request the transpilation service results using the task_id.

task_id=resp.json()['task_id']
res = requests.get(url=f"https://cloud-transpiler.quantum.ibm.com/transpile/{task_id}", headers=headers)
 
if res.json().get("state") == "SUCCESS":
    resulting_qasm=res.json().get("result")[0].get("qasm")
 
print(resulting_qasm)

Output

OPENQASM 3.0; include "stdgates.inc"; gate rzx_140040114706704(_gate_p_0) _gate_q_0, _gate_q_1 {   h _gate_q_1;   cx _gate_q_0, _gate_q_1;   rz(pi/4) _gate_q_1;   cx _gate_q_0, _gate_q_1;   h _gate_q_1; } gate rzx_140040024191376(_gate_p_0) _gate_q_0, _gate_q_1 {   h _gate_q_1;   cx _gate_q_0, _gate_q_1;   rz(-pi/4) _gate_q_1;   cx _gate_q_0, _gate_q_1;   h _gate_q_1; } gate ecr _gate_q_0, _gate_q_1 {   rzx_140040114706704(pi/4) _gate_q_0, _gate_q_1;   x _gate_q_0;   rzx_140040024191376(-pi/4) _gate_q_0, _gate_q_1; } bit[2] c; rz(-pi) $0; sx $0; rz(pi/2) $0; rz(-pi/2) $1; sx $1; rz(-pi) $1; ecr $1, $0; rz(-pi/2) $0; sx $0; rz(pi/2) $0; rz(pi/2) $1; sx $1; rz(pi/2) $1; barrier $0, $1; c[0] = measure $0; c[1] = measure $1;

Next steps