# Bundle Facts Source: https://lumeo.nativ.sh/docs/bundle-facts Performance # How Lumeo stays at 0 KB What the browser actually downloads — brotli-compressed assembly size, measured 2026-05-13 (rc.45). ## Per-package breakdown Install only the satellites you use. Each row shows the brotli-compressed size that package adds to your published WASM app. Lumeocore — 135 components 400 KB Lumeo.Chartsopt-in satellite 120 KB Lumeo.DataGridopt-in satellite 100 KB Lumeo.Editoropt-in satellite 26 KB Lumeo.Motionopt-in satellite 18 KB Lumeo.Scheduleropt-in satellite 16 KB Lumeo.Ganttopt-in satellite 12 KB ## What's actually in the core .nupkg The .nupkg contains more than what reaches the browser. Here's the full inventory. Lumeo.dll 400 KB brotli 1.9 MB raw IL → 400 KB after WASM linker trimming + brotli compression. This is the only file the browser downloads from the Lumeo package. lumeo.css 49 KB Theme tokens, dark-mode variable swaps, and component-scoped styles. Generated by Tailwind v4 at build time — no CSS-in-JS, no runtime style injection. components.js 57 KB Focus traps, scroll lock, element measurement, and third-party canvas wrappers. JS is reserved for what Blazor genuinely cannot do in pure Razor. Build props + symbols ~50 KB MSBuild .props integration (auto-imports lumeo.css + components.js), PDB symbols for debugging. Never reaches the browser. Total: ~556 KB compressed in the .nupkg — matches the NuGet "Download package" badge. The 400 KB brotli number is just the DLL, which is the only thing the WASM linker ships to the browser. ## What's not in core The dependencies we said no to. Newtonsoft.Json AutoMapper ReactiveUI Theme-provider JS CSS-in-JS runtime Bootstrap CSS jQuery MudBlazor dependency tree Telerik runtime Syncfusion bloat Runtime reflection helpers Source generators in core hot path Newtonsoft.Json AutoMapper ReactiveUI Theme-provider JS CSS-in-JS runtime Bootstrap CSS Newtonsoft.Json AutoMapper ReactiveUI Theme-provider JS CSS-in-JS runtime Bootstrap CSS jQuery MudBlazor dependency tree Telerik runtime Syncfusion bloat Runtime reflection helpers Source generators in core hot path Newtonsoft.Json AutoMapper ReactiveUI Theme-provider JS CSS-in-JS runtime Bootstrap CSS ## How it compares Brotli-compressed DLL size for the core package of each library. Library Core brotli size Note You Lumeo (core) 400 KB Brotli DLL — measured 2026-05-13 (rc.45) FluentUI Blazor ~500 KB Approximate; varies by component set referenced MudBlazor ~600 KB Approximate; typical published-app measurement Radzen Blazor ~700 KB Approximate; includes bundled JS interop Telerik UI Blazor ~1 MB+ Estimate; runtime licensing + JS runtime included \* Approximate brotli sizes for the core library DLL of each project at their latest stable release as of 2026. Independent verification recommended — numbers vary by build configuration and linker trimming. ## Heavy features are opt-in Don't need charts? ECharts never touches your build. Don't need a data grid? ClosedXML and QuestPDF aren't downloaded. 120 KB ### Charts Lumeo.Charts ECharts lazy-loaded only when a chart component mounts — never included unless you reference the package. 100 KB ### DataGrid Lumeo.DataGrid ClosedXML + QuestPDF are pulled in only when the package is referenced. Full virtualization, group-by, and export — on demand. 26 KB ### Rich Text Editor Lumeo.Editor TipTap JS lazy-loaded at component mount time. The DLL is only 26 KB — the heavy JS only streams when the editor renders. ## Why brotli, not .nupkg? NuGet shows 1.35 MB for the core .nupkg — here's what that actually means. Why isn't .nupkg size the right number? What does WASM linker trimming do? How was this measured? Developer experience ## Hot Reload that actually works Six architectural choices that keep `dotnet watch` fast and reliable on Lumeo apps — the same choices most Blazor UI libs make differently and pay for in slow rebuilds, stale styles, or forced full-restart loops. ### No Blazor CSS isolation Lumeo styles every component via Tailwind utility classes composed directly in markup. Tailwind v4 watch mode regenerates the single utility bundle in under 100 ms; the browser swaps it without losing state. What other libs do Libraries that rely on Blazor's per-component .razor.css isolation generate a new scoped-class hash on every change, force the SDK to re-emit the static-web-assets manifest, and often invalidate browser caches mid-session. ### Theme is CSS variables — not a C# object Switching themes in Lumeo means swapping --color-primary, --color-background, etc. in lumeo.css. No C# rebuild needed. dotnet watch picks up the CSS change and the browser re-paints with the new tokens. What other libs do MudThemeProvider passes a C# MudTheme record via CascadingValue. Editing colors requires recompiling C#, which triggers a delta-rebuild and re-render of every consuming component — Hot Reload often falls back to full restart. ### No source generators in the runtime hot path Lumeo.SourceGenerators only emits code for the opt-in \[LumeoForm\] attribute. Normal component edits never re-run a generator, so the dotnet watch inner loop is just Roslyn incremental compile + DOM patch. What other libs do Libraries that wrap every component in a base-class source generator (or AOT-style codegen) re-run the generator on every keystroke — multi-second incremental builds, and Hot Reload often gives up entirely. ### No reflection in the render path DataGridColumn.GetValue is a compiled Expression> cached per field (rc.44). Component parameters are strongly typed records. Hot Reload can swap method bodies without invalidating any cached type-handle metadata. What other libs do Reflection-heavy libs (PropertyInfo.GetValue, Activator.CreateInstance in render) cache Type instances that don't refresh on Hot Reload — you get "works after restart" bugs because old reflection caches are still alive. ### CascadingValue composition, not inheritance Compound components like Select / SelectTrigger / SelectContent share state via a record passed through CascadingValue. Each Razor file is independent and Hot Reload swaps it in isolation. What other libs do Libs with deep inheritance (MyButton : MudFormComponent : MudComponentBase) force the runtime to rebuild the whole class table when a base changes. Hot Reload prints "unable to apply edits" and you lose state. ### Razor SDK + Tailwind watch — one CSS bundle lumeo.css + lumeo-utilities.css are two files generated by Tailwind from your source. dotnet watch + npm run watch:css run in parallel; CSS swaps don't go through Blazor at all. No virtual-DOM diff for visual-only changes. What other libs do CSS-in-JS libs (or libs shipping a JS theme runtime) need to re-execute JS to recompute styles on every component touch — slower, and sometimes blocked by Blazor's circuit lifecycle. The net effect Edit a Razor component → DOM patches in ~120 ms. Edit `lumeo.css` or a theme variable → CSS swaps in ~50 ms with zero C# rebuild. Edit a Lumeo source-of-truth record (e.g. `DataGridColumn`) → delta build + DOM patch in under a second. No "Hot Reload not supported, restarting" spinner on the inner loop. ## See it for yourself Add Lumeo to a project, publish it, and measure. We believe the numbers. [Get Started](/docs/installation) [GitHub Releases](https://github.com/mberger/lumeo/releases)