Installation

One package, one optional service registration.

Install the package#

dotnet add package Deja

Deja multi-targets net8.0, net9.0 and net10.0 and works on both Blazor WebAssembly and Blazor Server. It has no third-party dependencies.

Register the cache (recommended)#

AddDeja() registers the shared query cache. It's opt-in: without it, everything still works, but keyed queries don't share results across components.

Program.cs

using Deja;

builder.Services.AddDeja(options =>
{
    options.DefaultStaleTime = TimeSpan.FromSeconds(10);
    options.DefaultCacheTime = TimeSpan.FromMinutes(5);
});

The options shown are this site's own configuration. Every property has a sensible default — see DejaOptions for the full list.

Blazor Server: keep it Scoped

AddDeja() registers DejaClient as Scoped deliberately: one cache per browser tab on WebAssembly, one per user circuit on Server. Re-registering it as a singleton on Blazor Server would share one user's cached API responses with every other connected user — a data leak, not a performance win.

Add the using#

_Imports.razor

@using Deja

Inherit the component base#

Components that own queries or mutations inherit DejaComponentBase, which attaches to declared state and re-renders the component when it changes:

@inherits DejaComponentBase

Continue with the quick start.