Teams ask which LLM is HIPAA-compliant, and the answer rearranges the question: none are, because compliance is a property of deployments — the infrastructure, the serving configuration, the data flows — and a perfectly compliant program can run an open-weights model while a certified-looking vendor stack fails its audit. The deployment framing converts anxiety into procedure, and this page is the procedure.
Quick Answer: How Do You Host an LLM Under HIPAA?
Four steps. 1) Choose the route: API model under vendor BAA (zero-ops, shared-processing terms) versus self-hosted weights (full control) — PHI-heavy workloads usually land on self-hosting. 2) Infrastructure: a BAA-covered environment whose scope contains your serving stack — single-tenant environments simplify scope to the estate boundary. 3) Serving controls: the inference path becomes a PHI system — access control, audit logging of prompts and outputs, retention policy, encryption. 4) Data flows: harden ingestion, serving, and egress — no PHI in telemetry or third-party hooks. Then verify before PHI flows: BAA scope matched, controls exercised, synthetic prompts traced through every store, incident scenario walked.
Prerequisites: Model Route and the Deployment Frame
Two decisions frame everything. The model route: an API model under a vendor BAA (available for specific models — the trade is zero-ops against shared-infrastructure terms and limited control) versus self-hosting open or licensed weights (the trade is full stack control against the hosting work this page describes) — and for PHI-heavy workloads the control argument usually lands on self-hosting. The deployment frame: no model is HIPAA-certified, deployments are — which means readiness is a property of your configuration (infrastructure, serving, data flows), built and verified per deployment, never inherited from the model card or the vendor logo.
| Route | You Get | You Trade |
| API under vendor BAA | Zero operations, vendor scale | Shared-processing terms, limited control |
| Self-hosted weights | Full stack control | The hosting procedure this page describes |

The deployment frame — the one every OneSource Cloud healthcare environment is documented against — explains why the route decision matters less than teams fear: whichever route wins, the same three hosting layers follow — infrastructure, serving controls, data flows — with the API route outsourcing the first layer and keeping the other two, and the self-hosted route owning all three. The readiness work is the same shape either way.
The Steps: Infrastructure, Serving Controls, Data Flows
Build in three layers. Infrastructure: a BAA-covered environment whose scope actually contains your serving stack — the verification this batch's hosting page details, with single-tenant environments simplifying scope to the estate boundary. Serving controls: the inference path becomes a PHI system — access control on the serving API, audit logging of prompts and outputs, a retention policy for prompt and output stores, and encryption throughout. Data flows: harden every path PHI travels — ingestion (de-identification where possible before prompting), the serving path (no PHI in telemetry or third-party instrumentation), and egress (outputs to PHI-classified stores only) — the data-flow audit that finds the log line, the analytics hook, or the error report quietly carrying prompts to nowhere.
| Layer | Controls | Classic Gap |
| Infrastructure | BAA scope containing the stack | Serving tier outside eligible services |
| Serving | Access, audit, retention, encryption | Prompt stores without PHI controls |
| Data flows | Ingestion, serving path, egress hardened | Telemetry and hooks leaking prompts |
The serving layer is where LLM deployments differ from every HIPAA guide written for databases, and where the serving environments OneSource Cloud delivers on single-tenant bare metal keep the inference path inside one auditable estate: the prompt and output stores are PHI systems the moment clinical text flows, and they inherit every duty — access control, audit, retention, deletion — that the EHR database carries. Teams that treat the serving stack as infrastructure plumbing discover the distinction during incident response, which is the expensive classroom.
Verification: The Pre-PHI Checklist
Run the pre-PHI checklist against the deployed stack, not the plan: confirm the BAA scope language matches the deployed architecture verbatim; exercise the access controls (revoke a test identity, confirm denial); generate synthetic prompts and trace them through every store and log the data-flow audit claimed (synthetic-first tracing finds what diagrams miss); verify retention settings on prompt and output stores; and walk one incident scenario end to end — who detects, who contains, what the notification clock produces. The verified state: the checklist documented with results, dated, attached to the deployment — readiness as evidence, which is what an auditor or your own incident response will actually ask for.
| Checklist Item | Passes When |
| BAA scope match | Language matches deployed architecture verbatim |
| Access exercise | Revoked identity denied, logged |
| Synthetic trace | Test prompts found only in sanctioned stores |
| Retention settings | Prompt and output stores configured to policy |
| Incident walk | Scenario produces detection, containment, clock |
The synthetic trace deserves its emphasis: it is the only checklist item that tests the system rather than the paperwork, and its findings — the prompt in the debug log, the hook sending context to a vendor — are exactly the gaps that diagrams never show. The infrastructure layer of the procedure arrives pre-verified on BAA-eligible single-tenant environments such as the ones documented at OneSource Cloud Healthcare AI — U.S. data centers, SOC 2 Type II audit readiness — leaving the serving and data-flow layers to the checklist that proves them.
FAQ
Can API-based LLMs ever be HIPAA-ready?
Yes, conditionally: where the model vendor offers a BAA covering their processing, API routes can be part of a compliant deployment — the conditions are real (PHI-bearing prompts flow to the vendor under their controls, retention and training-use terms bind them, and your data-flow audit extends to their boundary); for PHI-heavy or high-volume workloads the control trade usually favors self-hosting on BAA-covered infrastructure, which is why that route anchors the procedure here.
What proves an LLM deployment is ready before PHI flows?
The executed checklist: BAA scope matched to the deployed architecture, access controls exercised, synthetic prompts traced through every store and log, retention verified, and one incident scenario walked end to end — documented, dated, and attached to the deployment; the infrastructure layer arrives pre-verified on BAA-eligible single-tenant environments like the ones OneSource Cloud delivers with SOC 2 audit readiness, leaving the serving and data-flow layers to the checklist.