What's New in Blazor in .NET 10: Features Every ASP.NET Core Team Should Know in 2026
Blazor in .NET 10 is not a quiet maintenance release. It ships with changes that directly affect production systems — circuit resilience, significantly smaller script bundles, enhanced security integrations, and component model improvements that enterprise teams have been asking for since Blazor Web Apps were introduced. If your team is running Blazor Server or Blazor WebAssembly in production, or planning a migration to the Blazor Web App unified model, this release is worth your full attention.
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Circuit State Persistence: The Reliability Feature Blazor Server Has Always Needed
The most impactful change for Blazor Server production teams is circuit state persistence. In every version before .NET 10, a dropped connection meant lost state. Users who lost their browser tab's WebSocket link — even momentarily — would reload and find their form data, wizard progress, or UI state completely gone. That wasn't a Blazor bug; it was an architectural constraint.
.NET 10 changes this. When a Blazor Server connection is lost for an extended period, or when Blazor.pause() is called proactively, the framework can now persist the circuit state to browser storage. If the user reconnects without a full-page refresh, the component tree is restored from that persisted state rather than re-initialized from scratch.
What this means for enterprise teams:
- Multi-step forms, checkout flows, and wizard components can survive network blips without forcing users to restart
- You can now proactively pause circuits during planned reconnections (browser hibernation, mobile sleep mode)
- Circuit state persistence integrates with the existing
PersistentComponentStateAPI that teams using SSR rendering transitions may already be familiar with
What to watch: Persisted circuit state increases browser storage usage. Teams running sensitive financial or healthcare data through Blazor components should review what ends up in that persisted state and apply appropriate encryption or selective persistence.
Blazor Script Served as a Static Web Asset
Before .NET 10, the blazor.web.js and blazor.server.js scripts were served from embedded resources inside the ASP.NET Core shared framework. In .NET 10, they are served as static web assets — with automatic compression, cache fingerprinting, and CDN-friendliness.
The practical result: blazor.web.js drops from approximately 183 KB to around 43 KB — a 76% reduction in uncompressed script size. For applications serving Blazor to users on slower or metered connections, this is a meaningful improvement in time-to-interactive.
Fingerprinting also eliminates the stale-cache problem that plagued previous Blazor deployments when framework updates landed. Browser caches will automatically bust on version changes.
Enterprise impact: If your team manages Blazor deployments behind a CDN or reverse proxy, this change simplifies caching rules for the Blazor script. You can now treat blazor.web.js like any other fingerprinted static asset.
QuickGrid Gets the RowClass Parameter
The QuickGrid component — introduced as a high-performance data grid for Blazor — receives a practical but frequently-requested addition in .NET 10: the RowClass parameter.
Teams building admin panels, reporting dashboards, or data tables frequently need conditional row styling: highlight overdue items in red, archived records in grey, flagged rows in amber. Previously this required workarounds using custom column renderers or JavaScript interop.
The new RowClass parameter accepts a delegate that receives each row's item and returns a CSS class name (or null for no class). The result is clean, idiomatic Razor that keeps styling logic in C# where it belongs.
What to adopt now: If you are using QuickGrid in any capacity, RowClass is an immediate improvement. It is a purely additive change with no migration cost.
WASM Preloading and Performance Improvements
Blazor WebAssembly applications in .NET 10 benefit from improved preloading behaviour. The framework now supports more granular control over when and how WASM assemblies are fetched, reducing the perceived cold-start latency that has historically been WASM's biggest UX liability.
Additionally, .NET 10 Blazor WASM supports automatic memory pool eviction — the runtime more aggressively releases memory pools that are no longer needed, improving memory footprint for long-running WASM applications.
Who benefits most: Teams running Blazor WASM in Progressive Web App (PWA) or offline-capable configurations will see the biggest wins from both preloading improvements and the memory eviction changes.
Enhanced Security: OIDC, Entra ID, and Passkey Authentication
Security in Blazor .NET 10 has been substantially expanded across three areas.
OIDC and Microsoft Entra ID samples: Microsoft has updated and expanded the official Blazor Web App security samples to include a separate MinimalApiJwt web API project, demonstrating the correct pattern for calling external APIs from Blazor applications using token handlers. Teams integrating Blazor with enterprise identity providers now have first-party reference architectures to follow rather than piecing together approaches from blog posts.
Encrypted distributed token cache for web farms: The updated Entra guidance now covers encrypted distributed token caches for web farm hosting scenarios — a gap that previously sent teams to Stack Overflow or third-party libraries.
Passkey authentication via ASP.NET Core Identity: ASP.NET Core Identity in .NET 10 includes built-in WebAuthn/FIDO2 support, enabling passkey authentication (fingerprint, Face ID, hardware security keys) without third-party libraries. This integrates directly into the Blazor Web App authentication pipeline.
Enterprise adoption note: The OIDC and Entra ID sample restructuring reflects how Microsoft expects enterprise apps to be built on .NET 10. If your team has been deferring identity consolidation, the updated samples are the right starting point in 2026.
Hot Reload Improvements for Blazor WASM
Developer experience in Blazor WASM gets a meaningful boost in .NET 10 via improved Hot Reload support. In earlier versions, certain component changes — particularly changes to code-behind logic or component parameters — forced a full rebuild rather than a hot reload. .NET 10 expands the set of changes that Hot Reload handles gracefully, reducing the feedback loop for WASM development.
For teams with larger Blazor WASM applications where full rebuilds take 30-60 seconds, this has a direct impact on daily developer productivity.
Required Component Parameters
The component model in .NET 10 formalizes support for required component parameters — parameters marked as mandatory at compile time rather than only failing at runtime with a null reference. This was a long-standing friction point for teams building shared component libraries.
Required parameters integrate with the C# required keyword, allowing the compiler to enforce correct component usage at the call site. Teams maintaining internal design systems or component libraries will benefit from faster feedback and fewer runtime surprises.
PWA Service Worker Registration Changes
.NET 10 includes updates to PWA service worker registration to prevent stale caching issues that have affected Blazor WASM PWAs in previous versions. The registration pattern now aligns more closely with web standards best practices, reducing the frequency of users running stale app versions after deployments.
What to adopt: If your team operates Blazor WASM as a PWA and has experienced caching-related incident reports after deploys, upgrading to .NET 10's registration pattern is recommended.
ASP.NET Core Identity Metrics for Blazor Apps
New ASP.NET Core Identity-specific metrics — covering user management and login tracking — are now available in .NET 10. These metrics light up natively in Aspire dashboards, giving teams visibility into authentication activity without custom instrumentation.
Enterprise monitoring note: For teams already invested in .NET Aspire for observability, identity metrics are automatically available post-upgrade. No additional configuration is required.
What to Adopt Now vs. What to Evaluate Later
| Feature | Recommendation |
|---|---|
| Circuit state persistence | Adopt now — high impact for Blazor Server production apps |
| Blazor script as static asset | Adopt now — automatic benefit on upgrade, no code changes |
QuickGrid RowClass |
Adopt now — zero migration cost, immediate UX improvement |
| Passkey authentication (WebAuthn) | Evaluate — requires identity pipeline review, strong for new projects |
| WASM preloading improvements | Adopt now — passive gain on upgrade |
| Required component parameters | Adopt gradually — highest value in shared component libraries |
| PWA service worker updates | Adopt now if operating a PWA |
| OIDC/Entra ID sample patterns | Adopt for new builds — use as architecture reference |
What Does Blazor .NET 10 Mean for Enterprise Teams in 2026?
Blazor in .NET 10 closes several gaps that previously gave enterprise architects pause: circuit resilience, identity integration completeness, bundle performance, and compile-time component safety. The framework is no longer a promising preview-grade technology — it is a production-hardened platform with LTS support through .NET 10.
Teams evaluating Blazor for line-of-business applications in 2026 will find fewer reasons to defer. The combination of circuit state persistence, OIDC/Entra ID guidance, and WASM performance improvements answers the three most common objections: what happens when the connection drops, how do we integrate with our identity provider, and why is the initial load so slow.
For existing Blazor Server teams: circuit state persistence is the feature to prioritise in your upgrade planning. For WASM teams: the bundle size reduction and Hot Reload improvements make .NET 10 a clear upgrade path. For teams evaluating Blazor for the first time: the updated security samples give you a production-ready starting point.
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Frequently Asked Questions
What is circuit state persistence in Blazor .NET 10? Circuit state persistence allows Blazor Server applications to save the active circuit state (component tree and UI state) to browser storage when a connection is lost or proactively paused. When the user reconnects without a full-page refresh, the state is restored rather than re-initialized, preventing data loss during network disruptions.
How much smaller is the Blazor script in .NET 10?
The blazor.web.js script is approximately 76% smaller in .NET 10 compared to previous versions — reducing from around 183 KB to approximately 43 KB uncompressed. This improvement comes from serving the script as a static web asset with automatic compression and fingerprinting.
Does Blazor .NET 10 support passkey authentication natively? Yes. ASP.NET Core Identity in .NET 10 includes built-in WebAuthn/FIDO2 support for passkey authentication (fingerprint, Face ID, hardware security keys). This integrates into Blazor Web App authentication pipelines without requiring third-party libraries.
What is the QuickGrid RowClass parameter in .NET 10?
The RowClass parameter on the Blazor QuickGrid component accepts a delegate that receives each row's data item and returns a CSS class name. This enables conditional row styling — for example, highlighting overdue, archived, or flagged rows — directly in C# without JavaScript interop.
Is Blazor .NET 10 an LTS release? Yes. .NET 10 is a Long-Term Support (LTS) release, meaning it receives support for three years. Enterprise teams adopting Blazor on .NET 10 have until at least November 2028 for security updates and bug fixes.
Can circuit state persistence store sensitive data like authentication tokens? Circuit state persistence writes component state to browser storage. Teams should carefully control what data is included in persisted state. Authentication tokens should not be stored via this mechanism — they should remain in secure cookie or session storage managed by the identity pipeline, not the Blazor persistence API.
What changed with Blazor WASM Hot Reload in .NET 10? .NET 10 expands the set of component changes that trigger a Hot Reload rather than a full rebuild, including changes to component logic and parameter definitions. This reduces the feedback loop for WASM development, which previously required full rebuilds for many common code changes.
