# Alice & Bob

> Alice & Bob is a quantum computing company (Paris, with a Boston presence) building a universal, fault-tolerant quantum computer on cat qubits — superconducting qubits that are intrinsically protected against bit-flip errors. Its commercial developer surface is Felis Cloud, a Quantum Computing as a Service product that runs quantum circuits on Boson 4 cat-qubit QPUs and on physical- and logical-qubit emulators, reached through a public REST API and an open-source Qiskit provider.

<!--
generated: 2026-08-06
method: generated
source: Generated by the API Evangelist enrichment pipeline from apis.yml and the artifacts in
  this repository. Alice & Bob does not publish an llms.txt of its own — /llms.txt returns 404
  on felis.alice-bob.com and a 202 captcha challenge on alice-bob.com (probed 2026-08-06).
  This file is a third-party description, not a provider-published document.
-->

## What it is

Cat qubits are Alice & Bob's core technology: a qubit encoded in the two coherent states of a
superconducting resonator, whose bit-flip lifetime grows exponentially with the number of
photons while the phase-flip rate grows only linearly. That noise bias lets error correction
be done with much simpler codes — Alice & Bob's published claim is a reduction of up to 200x
in hardware needed for a useful large-scale machine. The trade-off shows up in the API: the
physical cat-qubit backends deliberately do not implement the Hadamard gate, because H is not
bias-preserving.

## Felis Cloud

Felis Cloud is the QCaaS product. It executes circuits on:

- **QPU targets** — real Boson 4 single-cat-qubit chips (`QPU:1Q:BOSON_4A`, `4B`, `4C`),
  hosted in Alice & Bob's own premises and available on a published schedule.
- **Emulator targets** — `EMU:1Q:LESCANNE_2020` (digital twin of the 2020 Lescanne cat qubit),
  `EMU:6Q:PHYSICAL_CATS`, `EMU:40Q:PHYSICAL_CATS`, `EMU:15Q:LOGICAL_EARLY`,
  `EMU:40Q:LOGICAL_TARGET`, `EMU:40Q:LOGICAL_NOISELESS`.

Backends are named `[EMU|QPU]:<n>Q:<NAME>`. The same emulators also run entirely locally,
inside the Python client, with no account and no API key.

Pricing is usage-time based: 1 free hour per month on each class, then $5,000/hour for the
Boson 4 QPU and $25/hour for emulators. Subscription and billing run through Google Cloud
Marketplace. Jobs are capped at 15 minutes so one user cannot monopolise the single chip.

## The API

- Base URL: `https://api-gcp.alice-bob.com/v1` (legacy host `https://api.alice-bob.com/`
  still answers)
- OpenAPI 3.1.0, 14 operations, served unauthenticated at
  [https://api-gcp.alice-bob.com/openapi.json](https://api-gcp.alice-bob.com/openapi.json)
- Reference (ReDoc): [https://api-gcp.alice-bob.com/reference](https://api-gcp.alice-bob.com/reference)
- Auth: `Authorization: Basic <API key>` — the raw key string after the literal word `Basic`,
  NOT base64-encoded RFC 7617 credentials. Keys are issued per person in the console.
- Every path on the API host returns `401 {"error":{"code":401,"message":"Unauthorized"}}`
  without a key.

The flow is: create a job against a target, upload the circuit as QIR, poll the job, download
the results.

| Operation | Method / path | Purpose |
|---|---|---|
| `list_targets_v1_targets__get` | GET /v1/targets/ | List backends and their configuration |
| `target_status_v1_targets__target__health_get` | GET /v1/targets/{target}/health | OK / NOK / OFF |
| `list_target_availabilities_v1_targets__target__availabilities_get` | GET /v1/targets/{target}/availabilities | Planned availability history |
| `create_job_v1_jobs__post` | POST /v1/jobs/ | Create a job for a target |
| `upload_input_v1_jobs__job_id__input_post` | POST /v1/jobs/{job_id}/input | Upload the QIR circuit (multipart), triggering execution |
| `get_job_v1_jobs__job_id__get` | GET /v1/jobs/{job_id} | Job state via `events[]` and `errors[]` |
| `list_jobs_v1_jobs__get` | GET /v1/jobs/ | List your jobs (page / limit) |
| `cancel_job_v1_jobs__job_id__delete` | DELETE /v1/jobs/{job_id} | Cancel an active job |
| `download_output_v1_jobs__job_id__output_get` | GET /v1/jobs/{job_id}/output | Histogram of measurements to counts |
| `download_memory_v1_jobs__job_id__memory_get` | GET /v1/jobs/{job_id}/memory | Per-shot measurement results |
| `download_transpiled_v1_jobs__job_id__transpiled_get` | GET /v1/jobs/{job_id}/transpiled | QIR after transpilation to the target gate set |
| `download_input_v1_jobs__job_id__input_get` | GET /v1/jobs/{job_id}/input | The QIR as submitted |
| `get_job_metrics_v1_jobs__job_id__metrics_get` | GET /v1/jobs/{job_id}/metrics | qpu_duration_ns, simulation_duration_ns |
| `check_health_v1_health__get` | GET /v1/health/ | Service liveness |

Input format is `HUMAN_QIR` (QIR Alliance intermediate representation); output format is
`HISTOGRAM`. Job state is the last entry in `events[]`, one of CREATED, FETCHING_INPUT,
INPUT_READY, COMPILING, COMPILED, COMPILATION_FAILED, TRANSPILING, TRANSPILED,
TRANSPILATION_FAILED, EXECUTING, SUCCEEDED, EXECUTION_FAILED, CANCELLED, TIMED_OUT.

## Client library

`pip install qiskit-alice-bob-provider` (Apache-2.0, PyPI, 1.2.0 stable). It ships
`AliceBobRemoteProvider(api_key)` — the reference implementation of the REST API — and
`AliceBobLocalProvider()`, the free in-process cat-qubit emulator. No first-party JavaScript,
Go, Java or .NET client exists.

## What is NOT published

Recorded so an agent does not go looking: there is no MCP server, no A2A agent card, no
GraphQL endpoint, no gRPC/protobuf, no webhooks or AsyncAPI (job completion is polled), no
`/.well-known/*` document of any kind, no idempotency key, no rate-limit headers or 429, no
deprecation policy or Sunset header, no published SLA, no security.txt and no trust centre.
The API's own OpenAPI declares no security schemes and no tags; see
`overlays/alice--bob-felis-cloud-overlay.yaml`.

## Links

- Documentation: https://felis.alice-bob.com/docs/
- API reference: https://api-gcp.alice-bob.com/reference
- The API page: https://felis.alice-bob.com/docs/reference/the_api/
- Getting started: https://felis.alice-bob.com/docs/getting_started/install_the_qiskit_provider/
- Connect to Felis Cloud: https://felis.alice-bob.com/docs/felis_cloud/connect_to_felis_cloud/
- Backends: https://felis.alice-bob.com/docs/backends/about_backends/
- Hardware availability: https://felis.alice-bob.com/docs/felis_cloud/hardware_availability_schedule/
- Live backend status: https://api-gcp.alice-bob.com/console/status
- Changelog: https://felis.alice-bob.com/docs/reference/changelog/
- FAQ: https://felis.alice-bob.com/docs/reference/faq/
- Console (API keys): https://api-gcp.alice-bob.com/console/
- Subscribe: https://console.cloud.google.com/marketplace/product/cloud-prod-0/felis-cloud
- GitHub: https://github.com/Alice-Bob-SW
- Qiskit provider: https://pypi.org/project/qiskit-alice-bob-provider/
- Support: https://felis.alice-bob.com/docs/contact_us/ (The Cat Tree, Slack)
- Company: https://alice-bob.com/