Architecture & Data Flow

This page is written for IT, information security, and network engineering teams evaluating Presto. It describes the topology: what runs on your infrastructure, what runs in Presto’s cloud, what data crosses the boundary between them, and what you need to allow through the firewall.

It is the companion to Security & Compliance, which covers the controls — encryption, authentication mechanics, HIPAA compliance, code signing, monitoring. This page covers the shape of the integration; that page covers how it is protected. Neither repeats the other.

Presto is a reporting workflow integration tool. It reads the report a radiologist is drafting in their existing reporting platform, restructures and formats it against the organization’s documentation templates, and writes the result back into that same draft.

The boundaries of that role matter more to a security review than any single control:

• Presto does not originate clinical findings. Everything it writes is derived from content the radiologist authored, plus — only if you enable it — findings produced by an AI vendor you selected. It restructures and formats that content, and can summarize it into an impression, which is a setting your organization controls and can turn off.
• Presto does not produce a diagnosis. It is a documentation tool, not a diagnostic one.
• Every Presto output is unsigned draft text inside the radiologist’s own template. The radiologist reviews, edits, and signs. Nothing enters the medical record without that signature.
• Presto never signs, files, or transmits a report downstream. The signed report leaves your reporting platform by the route it already uses today.
• Presto is not in the critical path. If Presto is unavailable, radiologists continue to dictate and sign natively in the reporting platform, exactly as they would without it.

Report merge and Capture are the product itself — both are active from day one. AIRPort is a separate integration you opt into, and it is the only one of the three that changes what crosses your firewall.

Only AIRPort changes the network picture, and it is drawn as a dashed line throughout this page. Without it, the deployment is a single outbound HTTPS connection from each workstation.

Three properties of this topology drive most security-review questions:

1. The workstation is the only Presto component inside your network. Nothing in Presto’s cloud reaches back into your environment.
2. Every connection is outbound-initiated from your side. No inbound firewall rule, no VPN, no site-to-site link, no IP allowlisting, no remote-access agent.
3. Presto Desktop and your reporting platform talk to each other locally, as two processes in the same interactive user session on the same machine. That traffic never touches the network.

All interaction happens locally, between two processes in the same interactive user session on the same machine. There is no network hop, no reporting-platform server involvement, and no elevated privilege.

Presto Desktop does not inject DLLs into the reporting platform, read its process memory, or modify its files or configuration. This matters for endpoint-security review: the mechanisms above are the vendor-supported and OS-supported ones, not the kind that EDR products flag as tampering.

On hotkeys and keystrokes. Presto Desktop registers a small set of specific, user-configurable hotkeys through the Windows RegisterHotKey API, and reads button presses from the radiologist’s existing USB dictation microphone. It does not install a low-level keyboard hook. It cannot and does not observe general keystrokes, and there is no keystroke logging anywhere in the product.

Presto runs in AWS, in US regions only.

• Public ingress to the application API passes through a web application firewall and load balancer. TLS 1.2 minimum; plaintext HTTP is redirected to HTTPS, never served.
• Application services and all data stores run in private network segments with no route from the internet.
• Data at rest is encrypted with AES-256, with automated multi-AZ backups.
• Each organization’s data is isolated at the database level, with no cross-tenant query path.
• Report merge runs on inference managed by Presto, in US regions, under BAA.

The controls behind each of these — key management, authentication mechanics, RBAC, logging and monitoring, vulnerability management — are covered in Security & Compliance.

The required capability, and for most organizations the whole deployment. The radiologist drafts as they do today; when they trigger a merge, Presto restructures and formats that draft against the organization’s documentation templates and writes it back.

The radiologist remains the author of record throughout. Presto never signs, files, or transmits a report to any downstream system — the signed report leaves your reporting platform by the route it already uses.

AIRPort is a separate capability from report merge, and most deployments do not use it. Report merge works with no AI vendor, no API key, and no vendor coordination of any kind. Skip this section if AIRPort is not in scope for you.

Where it is in scope:

• You choose the vendor and the model. Presto does not supply, recommend, or bundle a vision model, and does not select one on your behalf.
• You or your vendor host it. The model can run inside your network or as vendor SaaS — Presto is not involved in that decision and does not host models in customer environments.
• Presto receives the findings; it does not produce them. The vendor submits findings text to a documented ingest endpoint, and the radiologist’s workstation retrieves them later, by accession.
• Images never reach Presto. DICOM pixel data flows from your imaging systems to the model you chose. Presto receives the findings text that model produced.

The interface itself is public: see the AIRPort API reference for the exact contract your vendor implements.

An AIRPort integration is scoped by an API key issued to your organization. The mechanics:

Findings are presented for the radiologist’s review and selection. Nothing is inserted into a report without an explicit radiologist action.

Capture is part of the product and on by default. It adds no network path and no new integration.

The radiologist selects a region of their own screen — a sonographer worksheet, a DEXA worksheet, a prior report, an intake form, a labeled chart — and Presto returns the text it reads there for insertion into the draft: measurements, plus patient age and sex where those are present.

The image sent is a screen-region capture the radiologist initiated, not DICOM pixel data, and it travels on the same outbound HTTPS connection the workstation already uses. Because the radiologist chooses the region, the capture contains whatever is on screen inside it. Source images are held only briefly and then deleted automatically — see Data retention.

Not transmitted in any configuration: DICOM pixel data from your PACS, HL7 or FHIR messages, EHR records, or credentials for any of your systems.

All traffic is HTTPS on TCP 443, initiated from your network. No inbound rule is required on your perimeter.

A few notes IT teams usually ask about:

• Sign-in uses an ephemeral loopback listener at http://localhost:9876/callback. It is loopback-only and needs no firewall rule.
• Presto Desktop makes no plaintext HTTP connections over the network. The only exception is the loopback sign-in callback above, which never leaves the machine.
• TLS-intercepting proxies are supported. Presto Desktop validates certificates against the Windows trust store, so a properly installed corporate root CA works without further configuration.
• A minimum client version is signalled by the server and enforced by the client. Even with automatic updates disabled, workstations need a periodic update cadence to stay above the floor. Minimum-version changes are announced at least one release in advance — see the Installer Guide.

These hold for every deployment, with every capability enabled:

• No inbound connection to your network. No VPN, no site-to-site link, no IP allowlisting, no remote-access agent, no jump host.
• No PACS connection. Presto has no DICOM interface.
• No EHR or RIS integration. No HL7 interface, no FHIR interface, no writeback to the medical record.
• No network listening ports on the workstation. Presto Desktop opens an ephemeral loopback listener during sign-in, and a local named pipe restricted to the signed-in user so a second copy cannot start. Neither is reachable from the network.
• No administrator rights required to install or run Presto Desktop.
• No Presto staff credential grants access to any of your clinical systems.

Each integration uses an isolated credential. Revoking or rotating any one has no effect on the others, and there is no shared password anywhere in the design.

Your organization is provisioned as a dedicated tenant with its own subdomain and its own isolated data scope. An AIRPort API key is tenant-scoped: findings submitted with it are retrievable only within your tenant. There is no cross-tenant query path. For the mechanics, see Security & Compliance → Multi-Tenant Data Isolation.

• Security & Compliance — encryption, authentication, RBAC, code signing, monitoring
• Installer Guide — silent install flags, Intune and SCCM deployment, uninstall
• What is Presto.exe? — endpoint-security reference for the executable itself
• AIRPort API reference — the interface an AI vendor implements
• Business Associate Agreement

For a question this page does not answer, or to request a more detailed security assessment, contact your Presto account representative.