# Open core: qb-compiler vs QubitBoost Pro

qb-compiler is **open source and free**. It is the preflight layer for quantum execution: circuit
viability, backend recommendation, cost estimation, calibration-aware compilation, and QEC decoder-input
correctness (**ObservableGate**). All of it runs in CI, forever, for free.

**QubitBoost Pro** adds the team/lab/enterprise layer on top: signed and stored receipts, batch reports,
shared dashboards, CI policy bundles, and the broader governance stack (SafetyGate, DriftGate, the QEC
preflight bundle, Result Passport). Prove value for free, charge only once teams depend on the receipts.

## What's free (qb-compiler, open source)

| Capability | Command |
|---|---|
| Circuit viability preflight | `qbc preflight` / `qbc analyze` / `qbc diff` |
| **Hamiltonian integrity checks** | `qbc chem-audit` (text or `--json` receipt) |
| **Pre-submit measurement bill** | `qbc measure-plan` |
| **Receipt signing with your own key** | `selection_receipt(sign=True)`, `qb_compiler.signing` |
| **Offline receipt verification** | `qbc verify-receipt` |
| **Hash-verified public QEC corpora** | `qbc corpus list` / `show` / `verify` |
| **Ranked layout candidates and scores** | `CalibrationMapper.rank_layouts()` |
| Calibration-aware compilation + receipt | `qbc compile --receipt` |
| Mirror-circuit verification | `qbc verify` |
| **Cross-vendor fidelity-per-dollar ranking** | `qbc when` (text or `--json` advice receipt) |
| **ObservableGate: QEC DEM correctness audit** | `qbc dem-audit` (text or `--json` receipt) |
| **Observable-preserving DEM canonicalization** | `qbc dem-canonicalize` |
| CI-safe exit codes (0 / 1 / 2) | all of the above |
| Python API, notebooks, docs | |

The `--json` receipt is an unsigned, machine-readable community-tier artifact you can store and diff
yourself.

`qbc when` ranks across every configured vendor rather than one, and its `Data` column states whether
each number is validated on that backend's real hardware or a model estimate. Only IBM is validated
today, so most rows read `UNVALIDATED`. Turning those into measurements is what the Pro custom
vendor adapters and live calibration feeds are for.

## What's QubitBoost Pro (paid)

| Capability | Notes |
|---|---|
| **Managed keys and countersigning** | signing with your own key is free and always will be; what Pro adds is a key you do not have to hold, a countersignature from a party that is not you, and receipts that stay checkable after the machine that made them is gone |
| **Batch audit reports** | `dem-audit ./dems/` over a whole directory, rolled into one report |
| **CI policy bundles** | team policy files, GitHub/GitLab gate templates |
| **Receipt dashboard + history** | hosted, shared, searchable receipt storage over time |
| **DriftGate / SafetyGate / QEC-preflight bundle** | the governance stack |
| **Result Passport** | end-to-end provenance for a quantum result |
| **Deep QEC audit (services)** | private DEM/decoder audit + report + recommendations |
| Custom vendor/backend adapters, private support | |

Pro is in development at <https://qubitboost.io/compiler>.

## Design principle

> Every check becomes a receipt. The check is free; the trusted, signed, stored, team-shared receipt is
> the product.

ObservableGate is the first of them (fidelity receipt · drift receipt · ObservableGate receipt ·
SafetyGate receipt · QEC preflight receipt · Result Passport). The Pro layer is additive and never
blocks the open-source path.