One key, one call.

1. Mint a key

Keys are created in the console, which also runs a verification without a key so you can see the exact value before wiring CI. The full key is displayed once, at creation, and is not recoverable afterwards. Up to ten active keys per account; revoke from the same view.

cq_live_a1b2c3d4e5f6_…

2. Verify a circuit

Send OpenQASM 2 or 3 with the observable you care about. The response carries the exact value and what the run cost.

curl -X POST https://catalyst-q.strategic-innovations.ai/api/v1/execute \
  -H "Authorization: Bearer $CATALYST_Q_KEY" \
  -H "content-type: application/json" \
  -d '{
    "qasm": "OPENQASM 3.0;\nqubit[4] q;\nh q[0];\ncx q[0], q[1];",
    "observable": { "type": "expectation", "pauli": "ZZ" }
  }'

{
  "ok": true,
  "result": { "status": "completed", "exact": true, "value": 1 },
  "usage": {
    "declared_qubits": 4,
    "credits_charged": 2,
    "credits_remaining": 98,
    "duration_ms": 91
  },
  "account": { "tier": "free", "key_id": "a1b2c3d4e5f6" }
}

3. Certified observables

Send a circuit and up to 16 observables. Each value returns with its certificate; a job whose bundle would exceed your tier's word budget is refused with the size it reached and charges nothing.

curl -X POST https://catalyst-q.strategic-innovations.ai/api/v1/observables \
  -H "Authorization: Bearer $CATALYST_Q_KEY" \
  -H "content-type: application/json" \
  -d '{
    "qasm": "OPENQASM 3.0;\nqubit[12] q;\nrx(-0.05) q;\nrzz(-0.1) q[0], q[1];\nrx(-0.05) q;",
    "observables": [ { "type": "mean_z" }, { "pauli": "ZZ", "qubits": [0, 1] }, { "pauli": "Y", "qubits": [5] } ],
    "initial": "0",
    "tau": 1e-8
  }'

{
  "ok": true,
  "result": {
    "status": "completed",
    "values": [
      { "observable": "mean_z", "value": 0.9950041652780258, "certificate": 0, "exact": true, "words_max": 24, "support_qubits": 12 },
      { "observable": "ZZ[0,1]", "value": 0.9900332889206208, "certificate": 0, "exact": true, "words_max": 4, "support_qubits": 2 },
      { "observable": "Y[5]", "value": 0.09983341664682815, "certificate": 0, "exact": true, "words_max": 2, "support_qubits": 1 }
    ],
    "front": { "tau": 1e-8, "word_budget": 60000, "gates": 25, "declared_qubits": 12 }
  },
  "usage": { "declared_qubits": 12, "credits_charged": 3, "credits_remaining": 97, "duration_ms": 4 }
}

Chart selection. If the circuit is a nearest-neighbour matchgate circuit from a Fock or uniform |+⟩ product state, the job runs in the fermionic chart and the response carries "chart": "fermionic" with every value exact at one credit each; otherwise "chart": "pauli_front". Pass "chart": "pauli_front" to force the bundle, or "fermionic" to refuse anything else. Every successful job returns record_id and permalink — a public page at /r/<id> with the values, certificate, circuit and a BibTeX entry, and JSON at /api/v1/records/<id>.

Supported gates: h x y z s sdg t tdg sx sxdg rx ry rz p u1 u2 u3 u cx cz cy ch swap iswap sqrt_iswap rzz rxx ryy cp cu1 crz crx cry ccx ccz cswap. Anything else — including measure, reset and custom gate definitions — is refused by name. Parameters are evaluated exactly (pi/4 is π/4). initial is one letter for all qubits or one per qubit from 0 1 + - r l. A gate-list body (circuit + qubits) is accepted too.

4. Coherent-error logical channel

curl -X POST https://catalyst-q.strategic-innovations.ai/api/v1/qec/coherent \
  -H "Authorization: Bearer $CATALYST_Q_KEY" \
  -H "content-type: application/json" \
  -d '{ "distance": 5, "epsilons": [0.05, 0.1, 0.2] }'

{
  "ok": true,
  "result": {
    "code": "rotated_surface_code",
    "rows": [ { "d": 5, "n": 25, "syndromes": 4096, "epsilon": 0.1,
                "p_logical_coherent": 1.892e-5, "p_logical_twirled": 4.470e-6, "ratio": 4.23,
                "coherent_offdiagonal": 9.32e-5, "normalization": 1 } ]
  },
  "usage": { "credits_charged": 6, "credits_remaining": 91 }
}

4b. Threshold sweeps

curl -X POST https://catalyst-q.strategic-innovations.ai/api/v1/qec/threshold \
  -H "Authorization: Bearer $CATALYST_Q_KEY" -H "content-type: application/json" \
  -d '{ "distances": [3, 5, 7], "ps": [0.04, 0.08, 0.12], "shots": 1000, "noise": "code_capacity" }'

Union-find decoder, rotated surface code, d ≤ 11, up to 24 (distance, p) points and 4,000 shots per point per call; noise is code_capacity or phenomenological (d rounds with measurement errors). One credit per 500 shot-rounds per point. A call that passes the 15-second wall returns the rows it finished with status: "partial".

4c. Certified jobs above the budget

curl -X POST https://catalyst-q.strategic-innovations.ai/api/v1/jobs -H "Authorization: Bearer $CATALYST_Q_KEY" -H "content-type: application/json" \
  -d '{ "kind": "fermionic_large", "summary": "TFIM quench, 400 sites, T=8, mean Z and ZZ", "payload": { "n": 400 } }'

Kinds: observables_large, fermionic_large, qec_coherent_d7, verification, other. We reply by email with a scope and a fixed price; nothing is charged at request time. GET /api/v1/jobs lists your requests.

5. Verify a circuit at width

The width-side route from the first record: operator identity at a million declared qubits.

curl -X POST https://catalyst-q.strategic-innovations.ai/api/v1/execute -H "Authorization: Bearer $CATALYST_Q_KEY" \
  -H "content-type: application/json" -d '{ "qasm": "...", "observable": { "type": "expectation", "pauli": "ZZ" } }'

6. Check your balance

curl https://catalyst-q.strategic-innovations.ai/api/v1/usage \
  -H "Authorization: Bearer $CATALYST_Q_KEY"

Errors

Every error names the problem and the fix, and carries a docs link.

Scope

These routes return typed observables with certificates. None of them returns shot counts — read the published scope before integrating.