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Routes And Render Modes

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github-actions[bot] edited this page Aug 10, 2026 · 5 revisions

Routes and render modes

A route is a URL + render mode + metadata + offline strategy. Render mode is a per-route property. SEO is enforced by the build, not described in a guide.

v1.0.0 As of 2026-08. Stable API — semver from here (Upgrading).

The canonical shape

export const config = defineRoute({
  render:     'isr',                  // static | isr | ssr | stream | spa
  revalidate: { tags: [tag.post] },
  prerender:  () => db.posts.slugs(),
  offline:    'precache',             // precache | runtime | network-only
  hydrate:    'visible',              // idle | visible | interaction | never
  budget:     { js: '40kb', lcp: 2000 },
  meta:       ({ post }) => ({ title: post.title, description: post.excerpt,
                               og: { image: post.cover }, ld: ld.Article(post) }),
});
Aspect Rule
Projects to router entry, prerender list, sw.js precache/runtime rule, sitemap + RSS row, <head> + JSON-LD, per-route budget check
Owns render mode, hydration timing, metadata, offline strategy
Never touch the DB directly, hold business logic, or omit meta.description in site/ — that is a build error

The descriptor

route is the one primitive whose façade is a normalized descriptor rather than a set of projection methods, because a route declares no behaviour to project. It is read by the router, the prerenderer, sw.js generation, the sitemap and the budget check, and the descriptor's job is to hand all five one shape so none of them branches. There is no .describe() on a route either — describeRoutes() is the one route list.

Member Is Rule
kind: 'route' the brand lets the registry reject a non-route export. isRouteConfig(value) is the guard
meta(data) the <head> producer always returns a promise. A synchronous declared meta is wrapped, and a meta that throws synchronously becomes a rejection — so await config.meta(data) is the one way to fail as well as the one way to succeed, and no consumer branches on a thenable
budget the per-route limits always an object, {} when undeclared, rather than a second undefined-check at every call site
render revalidate prerender offline hydrate policy the declaration, carried through unchanged. Optional keys are omitted, never set to undefined
the whole object Object.freezed no consumer can mutate the route another consumer is about to read

The always-present budget does not weaken the site/ JS-budget check. budget is always an object, but its fields stay optional — so budget.js === undefined still means "this route declared no JS budget", and a site/ route that opts into any hydrate other than never without one is X_ROUTE_MODE_INVALID, exactly as before the normalization. Measuring the declared numbers against the built output is the separate concern in Budgets, below.

Validation runs at module evaluation. defineRoute checks the shape and the mode-local invariants immediately, so a bad route fails at build time rather than on the first request in production.

Checked Where Code
offline present and a known strategy defineRoute X_ROUTE_OFFLINE_MISSING
meta is a function defineRoute X_ROUTE_META_MISSING
mode-local: known render and hydrate; static with a policy or a revalidate; isr with no trigger; ssr with a prerender; spa with no policy defineRoute X_ROUTE_MODE_INVALID
surface-dependent: mode allowed on the surface; site/ hydration without budget.js; stream with no <Suspense>; prerender on a non-prerenderable mode registerRoute X_ROUTE_MODE_INVALID
the config came from defineRoute and not straight from the author registerRoute X_ROUTE_UNNORMALIZED
two files claiming one URL registerRoute X_ROUTE_DUPLICATE

The split is about what is knowable, not about strictness: everything decidable from the config alone is decided at import; the rest needs the file's surface, which only the route table knows.

Five render modes

Mode Behavior Use
static built once, served as a file marketing, docs
isr static + background regen on tag/TTL catalogs, profiles
ssr per-request full render fresh SEO pages
stream static shell flushed instantly, holes streamed default for app pages
spa shell only, client fetches dashboards behind auth
Surface Default Allowed
site/ static static, isr, ssr
app/ stream stream, spa, ssr
api/ n/a no rendering at all

A mode outside a surface's allowed set is a build error, not a runtime fallback. Surfaces and their boundaries: Project layout.

Why stream is the app default

An authed page needs fresh data and fast first paint. ssr gives freshness and a slow TTFB (the whole page waits for the slowest query). spa gives an instant shell, a spinner farm, and no HTML for anything. stream gives both halves: shell now, data as it resolves.

export default function Dashboard() {
  return (
    <Layout>
      <Header />                                {/* in the first flush */}
      <Suspense fallback={<StatsSkeleton />}>
        <Stats />                               {/* streamed when the query resolves */}
      </Suspense>
      <Suspense fallback={<FeedSkeleton />}>
        <Feed />                                {/* independent hole, independent flush */}
      </Suspense>
    </Layout>
  );
}

Solid's fine-grained reactivity is what makes this cheap:

Property Consequence
No VDOM streamed HTML is patched into place; nothing re-renders to reconcile
Signals, not component re-execution a resolved hole updates the exact DOM nodes bound to it
No hydration pass over the shell the static shell costs 0 hydration work — a <Suspense> boundary hydrates only its own island, only when its hydrate timing fires
Compile-time templates the shell's JS is markup-shaped, not a component tree to replay

In a VDOM framework a streaming shell still pays for hydrating the whole tree, which is why streaming there buys TTFB but not TBT. Here it buys both.

Independent holes each resolve their own queries; the tier-1 request memo means three holes reading the same query hit Postgres once.

hydrate timings

Value Wakes when Use
idle after first paint, on requestIdleCallback default in app/ — above-the-fold interactivity
visible the island intersects the viewport below-the-fold lists, comment threads, charts
interaction first pointer/focus/key event on the island menus, modals, popovers, dropdowns
never not at all — server HTML is final static islands, rendered markdown, badges

Hydration is per-island, never per-page. A blown budget.js is a build failure, so islands cannot quietly accumulate.

Budgets

Per route. budget.js in bytes, budget.lcp in milliseconds.

Check Source of truth
Per-route JS bytes budget.js on the route; measured from the real bundle graph
LCP / CLS / TBT headless Lighthouse against the built output, median of N runs
Lighthouse SEO + a11y scores minimum thresholds in app.config.ts, defaults 100 / 95
Precache size total sw.js precache set, see PWA and offline
Regression budgets ratchet — the recorded baseline can tighten, never loosen silently

A blown budget is a build failure, not a warning:

x verify
  ✓ typecheck            ✓ import boundaries      ✓ migration drift
  ✓ lint                 ✓ tests (6 types)        ✓ contract diff
  ✗ budgets
      site/pricing   js 61kb > 40kb   (chart.js via shared/ui/button.tsx)
      app/reports    lcp 2400 > 2000

Failures name the cause — the transitive import that added the bytes — because "bundle too big" without a chain is not an instruction. x verify --json emits the same content machine-readably.

SEO enforcement

Concern Enforcement
meta.title missing on any route build error X_SEO_NO_TITLE
meta.description missing on a site/ route build error X_SEO_NO_DESCRIPTION + fix: add description to meta in <file>
Description outside 50–160 chars build error, with the measured length
Duplicate title/description across routes build error — duplicate meta is a ranking bug, not a style issue
og.image missing on a shareable route build error; the generated fallback OG image must be opted into explicitly
Broken internal link build error, resolved against the route table
Missing alt on an <Image> build error
Canonical URL emitted for every route from the route table; never hand-written
robots / noindex a route-level field, so "we shipped staging to Google" is impossible without editing the route

A convention that isn't a build error doesn't exist. SEO is the archetype — every SEO regression in history was a documented convention someone forgot.

Typed JSON-LD

meta: ({ post }) => ({ /* ... */ ld: ld.Article(post) })

Helpers, typed against schema.org shapes:

Helper For
ld.Article posts, news, docs pages
ld.Product catalog and detail pages with price + availability
ld.Organization the site's own identity, emitted once
ld.BreadcrumbList derived from the route's path segments
ld.FAQPage Q&A blocks
ld.SoftwareApplication app landing pages
ld.Event dated, located events
ld.Recipe ingredient + step content

A missing required property is a type error, not a Rich Results Test failure discovered next week. Output is a single <script type="application/ld+json">, deduped per page.

Generated from the route table

Artifact Derived from Notes
sitemap.xml all indexable routes + prerender() results lastmod from the entity's updatedAt; auto-split at 50k URLs into a sitemap index
robots.txt route robots fields + app.config.ts sitemap reference included
rss.xml / atom.xml / feed.json routes tagged as feed items one declaration, three formats
llms.txt site/ route titles + descriptions machine-readable site summary for agents
404 / 500 required routes missing one is a build error

Nothing here is a plugin. Deleting a route removes it from the sitemap in the same build.

i18n routing

Feature Behavior
Locale routing /, /es/, /de/ from the configured locale list — no per-route wiring
hreflang full reciprocal set emitted per route, including x-default
Per-locale static output each locale is prerendered separately; no client-side locale swap on site/
Missing key renders ⟦key⟧ in dev, fails x verify in CI
Numbers / dates / money Intl.* with an explicit IANA timeZone and ISO currency; never a hand-rolled format
Localized metadata meta receives locale; a locale missing a description is the same build error

See I18n, Timezones and dates, Money.

Image pipeline

<Image src={post.cover} alt={post.title} sizes="(max-width: 700px) 100vw, 700px" priority />

One <Image> shape, one capability contract, stated once — in docs/idea/07-rendering-seo.md → Image pipeline: variants, srcset, inlined dimensions, the blur placeholder, the @ultimat3/core runtime, and the ImageTransformDriver seam AVIF/WebP variants come from. Restating it here would let the two copies drift.

Rules

  • render and offline are declared on the route or defaulted by surface. Never inferred at runtime.
  • revalidate.tags are typed handles from the tag graph — an unknown tag is a compile error (Caching and invalidation).
  • Routes never touch the DB directly. Data comes from a query.
  • A route holds no business logic. That is a service, behind an action.
  • prerender() must be deterministic and bounded — it is a build input.
  • Never hand-write a canonical URL, a sitemap entry, or sw.js.

Ultimate — v1.1.0 As of 2026-08. Stable API, semver from here. MIT licensed.

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