Are Power BI Custom Visuals Safe? What the Data Says (2026)

A Power BI custom visual is a .pbiviz package — bundled TypeScript/JavaScript (usually with a library like D3) plus a capabilities file — that Power BI runs inside a sandboxed iframe. That sandbox is the whole security story: the visual only ever sees the data the report author explicitly binds to it, which Power BI pushes in. It cannot reach your file system, read your other visuals or pages, touch the semantic model directly, or interfere with the rest of the Power BI service. Microsoft's security white paper puts it plainly: all custom visual code runs in a sandbox environment so that errant code cannot adversely affect the rest of the service. The flip side, in Microsoft's own words, is that Microsoft does not security-review most visuals before they reach the gallery — 'it's the customer's responsibility to review and determine whether custom visual code should be relied upon.' Sandboxing contains the blast radius; it does not, by itself, stop a visual from sending the data it legitimately receives somewhere else.

Certification is the dividing line that matters. A certified Power BI visual is one in AppSource that has met Microsoft's code requirements and passed testing specifically designed to confirm the visual does not access external services or resources. In practice that means a certified visual makes no outbound network calls at all: no HTTP/S or WebSocket requests leave Power BI, WebAccess privileges must be empty or omitted in capabilities.json, and the code may not use fetch, XMLHttpRequest, eval(), Function(), or unsanitized innerHTML. Microsoft reviews the actual source — submitted on a branch literally named 'certification' — and confirms the compiled package matches it. Certified visuals also unlock features uncertified ones can't use, such as export to PowerPoint and rendering inside subscription emails. Two honest caveats keep this balanced. First, certification is optional, so a visual being uncertified does not make it unsafe — many good visuals simply use a commercial library or connect to a map service and therefore can't qualify. Second, an uncertified visual can legitimately call external services: Microsoft notes, for example, that Bing Maps and ESRI visuals transmit data out of the Power BI service in order to render. That outbound capability is exactly what a governance review needs to reason about.

You don't have to take a vendor's word for it. Inside Power BI Desktop or the service, a certified visual shows a blue certified badge, and the 'Get more visuals' dialog offers a 'Power BI Certified' filter so you can browse only certified options. In AppSource, look for the small yellow badge on the visual's card, or the 'PBI Certified' badge on the visual's detail page. One timing gotcha worth knowing: after a visual is approved, Microsoft says its certification badge can take up to about three weeks to appear, so a brand-new certified visual might not display the badge immediately. If a visual claims certification but shows no badge in the Power BI interface, treat that claim as unverified until it does.

Strip away the anxiety and the concrete risk is narrow and specific: an uncertified visual that makes outbound web calls could, in principle, send the data bound to it — the summarized values and configuration it can see — to an external endpoint. It cannot exfiltrate your file system, your other reports, or your credentials; the sandbox never receives them. A few adjacent tenant settings widen what a visual can touch and are worth knowing: 'Allow downloads from custom visuals' lets a visual export its bound data to a file; 'AppSource Custom Visuals SSO' lets a visual request Microsoft Entra tokens that carry the signed-in user's name and email across regions; and browser local-storage access lets a visual cache data on the device. None of these are back doors — each requires the visual to be built for it and the tenant setting to be enabled — but they are the surface a security review should enumerate. The mitigation is straightforward and covered next: prefer certified visuals, and gate everything else through admin controls.

Power BI gives Fabric administrators direct levers, all under Tenant settings > Power BI visuals in the Fabric admin portal. The strictest is 'Add and use certified visuals only (block uncertified)': when enabled, only certified visuals render, and any uncertified AppSource or .pbiviz visual returns an error. One level broader is 'Allow visuals created using the Power BI SDK', which controls whether users can add AppSource or uploaded .pbiviz visuals at all. Both settings are disabled by default and can be scoped to specific security groups. Crucially, neither setting applies to your organizational store: an admin can vet a specific visual — even an uncertified .pbiviz — and publish it to the org store as an allow-listed exception that overrides the tenant restriction for just that visual. Microsoft even warns at that step that a visual uploaded from a file could contain code with security or privacy risks, so trust the author and source first. That is the recommended pattern: block broadly, allow-list deliberately. The UI toggles govern the Power BI service; to enforce the same policy in Power BI Desktop, set the matching Group Policy registry values.

Here's the governance gap the settings above can't fully close: even a certified visual is, to your security team, a black box — you trust Microsoft's review, but you never read the code. VizForge inverts that. Because VizForge generates the visual from your prompt and hands you the complete TypeScript source of the .pbiviz, the visual is auditable rather than opaque. Your reviewer can read every line, grep for fetch, XMLHttpRequest, WebSocket, or WebAccess privileges, and confirm for themselves that nothing phones home — the same properties Microsoft's certification checks, but on code you own and can diff over time. Generated visuals are built to avoid external network calls in the first place, which keeps them on the right side of that no-external-services requirement and lets you deploy them through your organizational store as a vetted, allow-listed visual. And because VizForge is priced as one-time credit packs rather than a subscription, owning that source isn't a recurring rental — the code is yours to audit, modify, and keep.

This explainer is the qualitative half of a bigger project. We're compiling a State of Power BI Custom Visuals 2026 data study, measuring how the ecosystem actually behaves: how many popular visuals are certified, how many request network, export, or SSO capabilities, and how those numbers are shifting. We won't quote figures we can't yet stand behind, so this piece sticks to what Microsoft's documentation verifiably states today; the measured numbers follow when the study publishes. Either way, if you govern a Power BI tenant the practical takeaways don't change — prefer certified, gate the rest through admin controls, and favor visuals whose source you can actually read.