# Qsolve

> Qsolve is a platform for running published quantum and hybrid workflows. Each workflow is benchmarked against the best classical method, every result is measured by the platform, and the price is quoted before a run starts. New accounts get 100 free credits (1 credit = 1 US dollar).

Qsolve is used by researchers and enterprises who run workflows, and by developers who publish workflows as Qiskit programs in a Git repository. Every page below is plain markdown; the full text of all pages is in llms-full.txt.

## Start here

- [What is Qsolve](https://qsolve.omlabs.co/docs/start/what-is-qsolve.md): Qsolve is a platform where you run validated quantum and hybrid workflows at a quoted price and see their measured results against the best classical method.
- [How a run works](https://qsolve.omlabs.co/docs/start/how-it-works.md): What happens between pressing Run and reading the result: sizing, the quote, the credit hold, execution, settlement and the run record you can open afterwards.
- [Quickstart](https://qsolve.omlabs.co/docs/start/quickstart.md): Create a Qsolve account, use the 100 free credits to run the max-cut workflow on the CPU simulator, and read the result in about five minutes.
- [Glossary](https://qsolve.omlabs.co/docs/start/glossary.md): Plain definitions of the terms you meet in Qsolve, from shots, fidelity and post-selection to QUBO, VQE, ZNE, noise models, transpilation and active spaces.
- [Frequently asked questions](https://qsolve.omlabs.co/docs/start/faq.md): Direct answers to common questions about Qsolve: cost, failed runs, quantum hardware, accuracy against classical methods, privacy, reproducibility and limits.

## Using Qsolve

- [Choosing a workflow](https://qsolve.omlabs.co/docs/use/choosing-a-workflow.md): How to find the right Qsolve workflow for your problem and judge it before you spend credits: search, track record, problem limits and the classical baseline.
- [Running an experiment](https://qsolve.omlabs.co/docs/use/running-an-experiment.md): How to set up and launch a Qsolve run: enter your input, pick a machine, adjust solver settings, set a spend limit, then approve the quote, stop or rerun it.
- [Reading your results](https://qsolve.omlabs.co/docs/use/reading-your-results.md): A guide to the Qsolve run page: the answer, the verdict against the classical baseline, fidelity and shots kept, circuits, cost, receipt and failed runs.
- [Accuracy, fidelity and noise](https://qsolve.omlabs.co/docs/use/accuracy-fidelity-and-noise.md): What Qsolve's accuracy, fidelity and shots-kept numbers mean, why correct hardware answers can have noisy distributions, and what is measured versus reported.
- [Machines and targets](https://qsolve.omlabs.co/docs/use/machines-and-targets.md): The three Qsolve targets (CPU simulator, GPU simulator, quantum computer), when to use each, what they cost, and how to read availability on the Compute page.
- [Credits and pricing](https://qsolve.omlabs.co/docs/use/credits-and-pricing.md): How Qsolve prices a run: the quote and hold formulas, how charges and returns are settled, spend limits and monthly budgets, with worked examples in credits.
- [Run records](https://qsolve.omlabs.co/docs/use/run-records.md): What Qsolve stores for every run, how to browse your run history, and how to read the evidence on a run page: receipt, circuits, events and credit movements.
- [Reproducibility](https://qsolve.omlabs.co/docs/use/reproducibility.md): How to reproduce a Qsolve run: the seed, workflow version and settings that fix a simulator result, what the receipt lets you compare, why hardware differs.
- [Data and privacy](https://qsolve.omlabs.co/docs/use/data-and-privacy.md): What data you give Qsolve when you run a workflow, what is stored and for how long, who can see it, and what a workflow's code can do with your input.
- [Qsolve for enterprises](https://qsolve.omlabs.co/docs/use/for-enterprises.md): How an enterprise team can evaluate a Qsolve workflow, control spend with limits and budgets, audit runs, and what its results can and cannot be relied on for.

## Build a workflow

- [What a Qsolve workflow is](https://qsolve.omlabs.co/docs/build/overview.md): A Qsolve workflow is a plain Qiskit program in a public Git repository plus a qsolve.yaml manifest; the SDK bridges to Qsolve, which runs and measures it.
- [Your first workflow](https://qsolve.omlabs.co/docs/build/your-first-workflow.md): Build, test and submit a Qsolve workflow from scratch: install the SDK, scaffold with qsolve init, run, validate, lint, benchmark, push to GitHub and submit.
- [Project layout](https://qsolve.omlabs.co/docs/build/project-layout.md): The files and folders of a Qsolve workflow repository, what each one is for, which are required, what is left out of the published snapshot and the size limits.
- [The manifest](https://qsolve.omlabs.co/docs/build/manifest.md): Complete reference for qsolve.yaml: every field, its type, default, valid values and limits, the error each mistake raises, how the platform uses it, and annotated examples from published workflows.
- [Writing the workflow](https://qsolve.omlabs.co/docs/build/writing-the-workflow.md): The contract of src/workflow.py: the Workflow class, what each method receives and returns, the Outcome object, solver details and how answers are rechecked.
- [Input and output schemas](https://qsolve.omlabs.co/docs/build/input-and-output-schemas.md): The two JSON Schemas of a workflow, the rules both must follow, alternatives for the input, and where to find the full references.
- [Input schema reference](https://qsolve.omlabs.co/docs/build/input-schema-reference.md): Complete reference for authoring schemas/input.json: which JSON Schema keywords the run form honours, every x-ui key with accepted values and effects, worked widget examples, validation rules and a pre-publish checklist.
- [Output schema reference](https://qsolve.omlabs.co/docs/build/output-schema-reference.md): Everything about schemas/output.json: how the answer is validated, how each JSON shape is drawn for users, every x-ui hint the answer view reads, what happens on misuse, with examples from published workflows.
- [Parameters](https://qsolve.omlabs.co/docs/build/parameters.md): How to declare parameters in qsolve.yaml: every field, the five types and their exact checks, ranges and choices, how defaults and overrides are validated, how the run form shows them and how they reach your code.
- [SDK reference](https://qsolve.omlabs.co/docs/build/sdk-reference.md): Overview of the qsolve-sdk Python package: install, import map of every module, how the pieces fit together, and which names are public API and which are internal.
- [SDK: the Workflow class](https://qsolve.omlabs.co/docs/build/sdk-workflow-class.md): Reference for qsolve.workflow: Workflow and every method you override, Outcome, Context (including emit and report_mitigation), and the exceptions WorkflowError, InvalidSolution, MethodUnavailable and QuantumNotAllowed.
- [SDK: runner and manifest](https://qsolve.omlabs.co/docs/build/sdk-runner-and-manifest.md): Reference for qsolve.runner, qsolve.manifest and qsolve.comparison: run_workflow, estimate_run, validate_input, RunOutput, load_workflow, Manifest and its parts, run_methods, headline and implementation.
- [SDK: backends and the Qiskit bridge](https://qsolve.omlabs.co/docs/build/sdk-backends-and-bridge.md): Reference for qsolve.backends and qsolve.bridge: targets and get_backend, Backend and AsyncBackend, AerBackend, FakeHardwareBackend, IBMBackend, RemoteBackend, QsolveBackend, QsolveSampler and QsolveEstimator.
- [SDK: metering and cost](https://qsolve.omlabs.co/docs/build/sdk-metering-and-cost.md): Reference for qsolve.metering and qsolve.sim: how the SDK records what crosses the backend, how fidelity and circuit size are measured, and how Estimate and run-time prediction feed the price quote.
- [SDK: results, events and circuit records](https://qsolve.omlabs.co/docs/build/sdk-results-and-events.md): Reference for qsolve.results, qsolve.events and qsolve.circuit_record: every field of Result, MethodResult, Metrics, Quality, Mitigation, CircuitStats, Provenance, Uncertainty and Estimate, plus emit, capture and the drawable circuit records.
- [SDK: testing, linting and the sandbox](https://qsolve.omlabs.co/docs/build/sdk-testing-and-benchmarks.md): Reference for qsolve.benchmark, qsolve.lint and qsolve.sandbox_entry: run_benchmarks, the gate and case models, check_quality, check_estimate, lint_workflow, Finding, and the framed protocol of the sandbox entry point.
- [Backends and targets](https://qsolve.omlabs.co/docs/build/backends-and-targets.md): How workflow code runs circuits through QsolveBackend, QsolveSampler and QsolveEstimator on simulators, noise models and quantum computers, and what Qsolve meters.
- [Error mitigation and fidelity](https://qsolve.omlabs.co/docs/build/error-mitigation-and-fidelity.md): How Qsolve measures fidelity, how to declare error mitigation with report_mitigation, how mitigated figures are scored and labelled, and what you may claim.
- [Lint codes](https://qsolve.omlabs.co/docs/build/lint-codes.md): Every error and warning code that qsolve lint and the submission's static checks can report, what triggers it, the message and how to fix it.
- [Benchmarks](https://qsolve.omlabs.co/docs/build/benchmarks.md): Every key of benchmarks/cases.yaml, the exact pass and fail rules, the eight validation gates, hardware cases, how results enter the track record and what the workflow page shows, with the lint code for each mistake.
- [The qsolve command line](https://qsolve.omlabs.co/docs/build/cli.md): Reference for every qsolve command, argument and option: init, validate, lint, run, estimate and test, with defaults, exit codes, output formats, environment variables, error messages and examples.
- [Validation and publishing](https://qsolve.omlabs.co/docs/build/validation-and-publishing.md): What happens when you submit a GitHub repository to Qsolve: the five stages, the checklist you see, limits and timeouts, how failures look and are fixed, and how a workflow is listed.
- [Private repositories](https://qsolve.omlabs.co/docs/build/private-repositories.md): Publish a workflow from a private GitHub repository: connect the Qsolve GitHub app, choose repositories, and what other people can and cannot see.
- [Versioning](https://qsolve.omlabs.co/docs/build/versioning.md): How Qsolve versions a workflow: the semver string in qsolve.yaml, the content digest and what it covers, what happens when you resubmit a version, what is stored per version, which version runs and what happens to old results.
- [The seven example workflows](https://qsolve.omlabs.co/docs/build/examples.md): A walkthrough of the seven published Qsolve example workflows: what each solves, its inputs, outputs and parameters, and what to learn from reading its code.
- [Troubleshooting](https://qsolve.omlabs.co/docs/build/troubleshooting.md): Real errors from qsolve lint, validation gates, the SDK and failed runs, with the cause of each and how to fix it, listed by the code or message you see.

## Optional

- [All documentation as one file](https://qsolve.omlabs.co/llms-full.txt): every page in full
- [Run an experiment](https://qsolve.omlabs.co/bench): the catalogue of published workflows
- [Compute](https://qsolve.omlabs.co/compute): which machines are available now