1. The SPA problem

In a SPA the initial HTML is almost empty and the content is built by JavaScript in the browser (in Blazor WebAssembly the .NET runtime is downloaded first, too). Many bots don't run JavaScript, or run it late and with limits: the result is incomplete indexing, generic titles and descriptions, empty previews when a link is shared and AI answers that never cite your site.

Prerendering hands each bot an already rendered HTML version of the page, with its content, its meta and Open Graph tags and the real status code (200, 404, redirect...), without changing anything in the app.

2. How it works

1. 1 A bot asks for a page Google, an AI bot or a social network asks for a URL of your site.
2. 2 Your integration recognizes it In the CDN, the server or a middleware the bot is recognized by its user agent and, instead of serving the SPA, the page is requested from the Jazui API with your token.
3. 3 Jazui renders it or serves it from cache It checks the token, the plan, the rules and that the site is verified. If the page is cached it returns it instantly; otherwise it opens it with Chrome, stores it and returns it.
4. 4 The bot gets the full HTML With the real status code (200, 404, redirect...). If Jazui is slow or fails, the integration serves the normal site.

To start: create the account, add the site, verify the domain (DNS or meta tag) and connect the integration.

3. What it includes

Render and cache

SEO and AI

Content

Metrics and account

4. Integrations

Choose where bots are recognized. Each card opens its guide in the Jazui documentation.

5. Jazui in a Blazor app with AstrolUI

Blazor served by ASP.NET Core (hosted WebAssembly or Blazor Web App): install Jazui.AspNetCore from the same AstrolUI feed and add the middleware before the static files and the fallback. It is the most robust option: if Jazui is slow or fails, the bot gets the normal page. The token goes in the Jazui__Token environment variable.

dotnet nuget add source https://nuget.astrolui.com/v3/index.json --name AstrolUI

dotnet add package Jazui.AspNetCore

// Program.cs of the ASP.NET Core app that serves the Blazor WebAssembly client

builder.Services.AddJazui(builder.Configuration);   // section "Jazui": Token, SiteUrl, Timeout...

var app = builder.Build();

app.UseForwardedHeaders();   // only behind a proxy or CDN

app.UseJazui();              // before the static files and the SPA fallback

app.UseStaticFiles();

app.MapFallbackToFile("index.html");

app.Run();

// Token: environment variable Jazui__Token (never in appsettings.json)

Static Blazor WebAssembly on IIS: add the «Jazui» rule as the first rule of the web.config the site already has (don't replace it: it carries the MIME types and Blazor's rules) and enable the ARR proxy and the server variables once per server. Behind Cloudflare, the bot IP comes from {HTTP_CF_CONNECTING_IP}. Turn the rule on once the site is verified in Jazui: with ARR, if Jazui answers with an error, the bot gets that error.

<!-- First rule of <rewrite><rules>, before the Blazor SPA fallback. Full bot list:

     https://docs.jazui.com/example_config/iis_web.xml -->

<rule name="Jazui" stopProcessing="true">

  <match url=".*" />

  <conditions logicalGrouping="MatchAll">

    <add input="{HTTP_USER_AGENT}#{QUERY_STRING}" pattern="^[^#]*(?:googlebot|bingbot|gptbot|chatgpt|claudebot|perplexity|facebookexternalhit|linkedinbot|whatsapp|...)|#.*_escaped_fragment_" />

    <add input="{REQUEST_METHOD}" pattern="^(GET|HEAD)$" />

    <add input="{HTTP_X_JAZUI}" pattern=".+" negate="true" />

    <add input="{URL}" pattern="\.(js|mjs|css|map|json|xml|txt|ico|png|jpg|svg|woff|woff2|wasm|dll|dat|blat|br|gz|pdf)$" negate="true" />

  </conditions>

  <serverVariables>

    <set name="HTTP_AUTHORIZATION" value="Bearer [JAZUI_TOKEN]" />

    <set name="HTTP_X_JAZUI_URL" value="https://{HTTP_HOST}{UNENCODED_URL}" />

    <set name="HTTP_X_JAZUI_CLIENT_IP" value="{REMOTE_ADDR}" />  <!-- behind Cloudflare: {HTTP_CF_CONNECTING_IP} -->

    <set name="HTTP_COOKIE" value="" />

  </serverVariables>

  <action type="Rewrite" url="https://api.jazui.com/Render" appendQueryString="false" />

</rule>

rem Once per server, as administrator: ARR proxy and the server variables the rule writes

%windir%\system32\inetsrv\appcmd.exe set config -section:system.webServer/proxy /enabled:"True" /commit:apphost

%windir%\system32\inetsrv\appcmd.exe set config -section:system.webServer/rewrite/allowedServerVariables /+"[name='HTTP_AUTHORIZATION']" /+"[name='HTTP_X_JAZUI_URL']" /+"[name='HTTP_X_JAZUI_CLIENT_IP']" /+"[name='HTTP_COOKIE']" /commit:apphost

On every page, so the SEO score goes up and previews look right:

• A <PageTitle> and a <HeadContent> with description, canonical and Open Graph (AstrolTitle accepts HeadContent): Jazui keeps them in the rendered HTML.
• A URL of its own for each piece of content and each language (like /jazui and /jazui/es in these docs), in the sitemap. Jazui can host the sitemap, robots.txt and llms.txt, and manage AI bots.
• Don't make the main content depend on a click or a scroll: what isn't painted on load isn't indexed.
• After publishing important changes, re-cache from the dashboard or with the cache API.

<PageTitle>Product X | MyStore</PageTitle>

<AstrolTitle Icon="astrol-basket" Text="Product X">

    <HeadContent>

        <meta name="description" content="Short description that will appear in Google" />

        <meta property="og:title" content="Product X" />

        <meta property="og:description" content="Preview text for WhatsApp, LinkedIn, X..." />

        <meta property="og:image" content="https://mystore.com/img/product-x.jpg" />

        <link rel="canonical" href="https://mystore.com/product/x" />

    </HeadContent>

</AstrolTitle>

6. API

Every integration calls GET https://api.jazui.com/Render?url= with the full encoded URL (or in the X-Jazui-Url header) and Authorization: Bearer with the account render token or a site token, kept by convention in the JAZUI_TOKEN variable (or Jazui__Token in .NET). Optional: botAgent, X-Jazui-Client-IP (the bot IP) and If-None-Match. The response is delivered to the bot only if it carries X-Jazui: true; with X-Jazui-Blocked the bot is blocked (403) and in any other case the normal site is served. To avoid loops, integrations let through requests that already carry the X-Jazui header. Never expose the token on the client.

There are also cache APIs (re-cache, purge), signed webhooks, blog and site files: see docs.jazui.com/api.

curl "https://api.jazui.com/Render?url=https%3A%2F%2Fexample.com%2F&botAgent=integration-test" \

     -H "Authorization: Bearer $JAZUI_TOKEN" -i

# Deliver the response to the bot only if it carries  X-Jazui: true  (any status: 200, 301, 404...).

# X-Jazui-Blocked = blocked bot (403). Anything else, or a timeout: serve the normal site.

7. Plans

Jazui has a free plan and monthly or yearly paid plans with a free trial. Prices and the limits of each plan are always up to date at jazui.com/plan.

8. Links