User problem. You want to read a PII-heavy document (a contract, a resume, an exported chat log) with every detected span highlighted by category, a filter in the sidebar, and a summary dashboard up top. The reading experience should feel like a normal document, not a form.

What Privacy Filter does here. The whole file goes through in a single 128k-context forward pass, so there's no chunking, no stitching, and span offsets line up directly with the rendered text. BIOES decoding keeps span boundaries clean through long ambiguous runs.

What gr.Server does here. You could wire this up in Blocks with gr.HighlightedText and a sidebar, and it would work. The reading experience we wanted (serif body, category filters that toggle CSS classes client-side instead of re-running the model, a summary dashboard that doesn't force a page re-render) was easier to hand-author than to compose. gr.Server lets us serve the reader view as a single HTML file and expose the model behind one queued endpoint:

Note the decorator: @server.api(name="analyze_document"), not a plain @server.post. That's the piece that plugs the handler into Gradio's queue, so concurrent uploads are serialized, @spaces.GPU composes correctly on ZeroGPU, and the same endpoint is reachable from both the browser and gradio_client with no duplicated code. The browser calls it with the Gradio JS client: