diff --git a/.github/workflows/e2e.yaml b/.github/workflows/e2e.yaml
index 3c87f319..d7c5ca2e 100644
--- a/.github/workflows/e2e.yaml
+++ b/.github/workflows/e2e.yaml
@@ -43,10 +43,24 @@ jobs:
         working-directory: packages/core
         run: pnpm build
 
+      - name: Build viewer
+        working-directory: packages/viewer
+        run: |
+          VITE_BUNDLE_HOST=http://localhost:4173 pnpm run build
+
+      - name: Copy fixtures
+        working-directory: packages/viewer
+        # The viewer build is configured to load data from the local server's
+        # static assets, so we populate the main branch location with fixture
+        # data, for deterministic testing.
+        run: |
+          mkdir -p dist/refs/heads
+          cp cypress/fixtures/main.min.json dist/refs/heads/main.json
+
       - name: Cypress run
         uses: cypress-io/github-action@v5
         with:
           browser: chrome
           build: echo "Start runs build"
-          command: pnpm --filter viewer run cy:run
-          start: pnpm --filter viewer run dev
+          command: pnpm --filter viewer run cy:run --config baseUrl=http://localhost:4173
+          start: pnpm --filter viewer run preview
diff --git a/packages/viewer/.github/workflows/ci-cd.yaml b/packages/viewer/.github/workflows/ci-cd.yaml
deleted file mode 100644
index c36cce3e..00000000
--- a/packages/viewer/.github/workflows/ci-cd.yaml
+++ /dev/null
@@ -1,114 +0,0 @@
-name: CI/CD
-on:
-  push:
-
-jobs:
-  test:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Cache node modules
-        uses: actions/cache@v2
-        env:
-          cache-name: cache-node-modules
-        with:
-          path: ~/.npm
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.os }}-build-${{ env.cache-name }}-
-            ${{ runner.os }}-build-
-            ${{ runner.os }}-
-      - name: Install
-        run: npm ci
-      - name: Lint
-        run: npm run lint:check
-      - name: Formatting
-        run: npm run fmt:check
-      - name: Test
-        run: npm run test:cov
-      - name: Report coverage
-        uses: coverallsapp/github-action@master
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Cache node modules
-        uses: actions/cache@v2
-        env:
-          cache-name: cache-node-modules
-        with:
-          path: ~/.npm
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
-          restore-keys: |
-            ${{ runner.os }}-build-${{ env.cache-name }}-
-            ${{ runner.os }}-build-
-            ${{ runner.os }}-
-      - name: Install
-        run: npm ci
-      - name: Build
-        run: npm run build
-      - name: Upload build
-        uses: actions/upload-artifact@v2
-        with:
-          name: public
-          path: public
-
-  e2e:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Cypress run
-        uses: cypress-io/github-action@v2
-        with:
-          build: npm run build
-          start: npm run start
-          record: true
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          CYPRESS_RECORD_KEY: ${{ secrets.CYPRESS_RECORD_KEY }}
-      - name: Capture screenshots
-        if: ${{ failure() }}
-        uses: actions/upload-artifact@v2
-        with:
-          name: screenshots
-          path: cypress/screenshots
-      - name: Capture videos
-        if: ${{ failure() }}
-        uses: actions/upload-artifact@v2
-        with:
-          name: videos
-          path: cypress/videos
-
-  release:
-    if: github.ref == 'refs/heads/master' || github.ref == 'refs/heads/dev'
-    runs-on: ubuntu-latest
-    needs:
-      - build
-      - test
-      - e2e
-    steps:
-      - name: Download build
-        uses: actions/download-artifact@v1
-        with:
-          name: public
-          path: public
-      - name: Release to dev
-        if: github.ref == 'refs/heads/dev'
-        run: |
-          aws s3 sync ./public s3://pi-base-viewer-dev
-        env:
-          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
-          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
-      - name: Release to prod
-        if: github.ref == 'refs/heads/master'
-        run: |
-          aws s3 sync ./public s3://pi-base-viewer
-        env:
-          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
-          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
diff --git a/packages/viewer/cypress/e2e/deduction.spec.ts b/packages/viewer/cypress/e2e/deduction.spec.ts
index ee728c86..7ef44934 100644
--- a/packages/viewer/cypress/e2e/deduction.spec.ts
+++ b/packages/viewer/cypress/e2e/deduction.spec.ts
@@ -1,6 +1,7 @@
 import { isLegacy } from '../constants'
 
 beforeEach(() => {
+  cy.clearAllLocalStorage()
   cy.intercept({ hostname: /pi-base-bundles/ }, { fixture: 'main.min.json' })
 })
 
diff --git a/packages/viewer/cypress/e2e/search.spec.ts b/packages/viewer/cypress/e2e/search.spec.ts
index 836e2b7c..3ab5df62 100644
--- a/packages/viewer/cypress/e2e/search.spec.ts
+++ b/packages/viewer/cypress/e2e/search.spec.ts
@@ -4,14 +4,15 @@ const search = '/spaces'
 
 describe('with a working remote', () => {
   beforeEach(() => {
-    cy.intercept({ hostname: /pi-base-bundles/ }, { fixture: 'main.min.json' })
+    cy.clearAllLocalStorage()
+    cy.intercept({ path: /main.json/ }, { fixture: 'main.min.json' })
   })
 
   it('searches by text and formula', () => {
     cy.visit(search)
 
-    cy.get('input[name="text"]').type('plank')
-    cy.get('input[name="q"]').type('metacom')
+    cy.get('input[name="text"]').focus().type('plank')
+    cy.get('input[name="q"]').focus().type('metacom')
 
     cy.url().should('include', 'text=plank').should('include', 'q=metacom')
 
diff --git a/packages/viewer/cypress/tsconfig.json b/packages/viewer/cypress/tsconfig.json
index f0fd98dc..04fc8da8 100644
--- a/packages/viewer/cypress/tsconfig.json
+++ b/packages/viewer/cypress/tsconfig.json
@@ -1,8 +1,13 @@
 {
-  "extends": "../tsconfig.json",
   "compilerOptions": {
+    "target": "es5",
+    "lib": [
+      "es5",
+      "dom"
+    ],
     "types": [
-      "cypress"
+      "cypress",
+      "node"
     ],
     "isolatedModules": false
   },
diff --git a/packages/viewer/package.json b/packages/viewer/package.json
index 46efc868..741bb3b0 100644
--- a/packages/viewer/package.json
+++ b/packages/viewer/package.json
@@ -9,6 +9,7 @@
     "cy:open": "cypress open",
     "cy:run": "cypress run",
     "dev": "vite",
+    "preview": "vite preview",
     "test": "vitest run",
     "test:cov": "vitest run --coverage",
     "test:watch": "vitest",
@@ -41,7 +42,7 @@
     "@types/katex": "^0.16.5",
     "@types/page": "^1.11.8",
     "@types/unist": "^2.0.9",
-    "cypress": "^12.17.4",
+    "cypress": "^13.3.3",
     "svelte": "^3.59.2",
     "svelte-check": "^3.5.2",
     "svelte-preprocess": "^5.0.4",
diff --git a/packages/viewer/src/constants.ts b/packages/viewer/src/constants.ts
index e7fe410f..e46dfeb4 100644
--- a/packages/viewer/src/constants.ts
+++ b/packages/viewer/src/constants.ts
@@ -1,5 +1,8 @@
+import { bundle } from '@pi-base/core'
+
 export const mainBranch = 'main'
 export const contributingUrl = `https://github.com/pi-base/data/blob/${mainBranch}/CONTRIBUTING.md`
+export const defaultHost = bundle.defaultHost
 
 export const build = {
   branch: import.meta.env.VITE_BRANCH || 'unknown',
diff --git a/packages/viewer/src/context.ts b/packages/viewer/src/context.ts
index 6137afba..7dfcdc77 100644
--- a/packages/viewer/src/context.ts
+++ b/packages/viewer/src/context.ts
@@ -39,18 +39,20 @@ function project(store: Store) {
 export function initialize({
   db = local(),
   errorHandler = Errors.log(),
+  host,
   gateway,
   showDev = false,
   typesetter = renderer,
 }: {
   db?: Local<Prestore>
   errorHandler?: Errors.Handler
+  host?: string
   gateway: Gateway.Sync
   showDev?: boolean
   typesetter?: typeof renderer
 }): Context {
   const pre = db.load()
-  const store = create(pre, gateway)
+  const store = create(pre, gateway, { host })
 
   db.subscribe(project(store))
 
@@ -79,17 +81,17 @@ export function initialize({
     until: Promise<unknown> = loaded(),
   ): Promise<T> {
     return new Promise((resolve, reject) => {
-      const unsubscribe = s.subscribe(state => {
+      var unsubscribe = s.subscribe(state => {
         const found = lookup(state)
         if (found) {
           resolve(found)
-          unsubscribe()
+          unsubscribe && unsubscribe()
         }
       })
 
       until.then(() => {
         reject()
-        unsubscribe()
+        unsubscribe && unsubscribe()
       })
     })
   }
diff --git a/packages/viewer/src/routes/+layout.ts b/packages/viewer/src/routes/+layout.ts
index 8a014a59..7c9319a0 100644
--- a/packages/viewer/src/routes/+layout.ts
+++ b/packages/viewer/src/routes/+layout.ts
@@ -1,7 +1,10 @@
-import * as errors from '../errors'
+import { initialize } from '@/context'
+import { defaultHost } from '@/constants'
+import * as errors from '@/errors'
+import { sync } from '@/gateway'
 import type { LayoutLoad } from './$types'
-import { initialize } from '../context'
-import { sync } from '../gateway'
+
+const bundleHost = import.meta.env.VITE_BUNDLE_HOST || defaultHost
 
 export const load: LayoutLoad = async ({ fetch, url: { host } }) => {
   const dev = host.match(/(dev(elopment)?[.-]|localhost)/) !== null
@@ -22,6 +25,7 @@ export const load: LayoutLoad = async ({ fetch, url: { host } }) => {
     showDev: dev,
     errorHandler,
     gateway: sync(fetch),
+    host: bundleHost,
   })
 
   await context.loaded()
diff --git a/packages/viewer/src/stores/index.ts b/packages/viewer/src/stores/index.ts
index f59f62ae..1c5f0344 100644
--- a/packages/viewer/src/stores/index.ts
+++ b/packages/viewer/src/stores/index.ts
@@ -1,21 +1,22 @@
-export { default as list } from './list'
-export { default as search } from './search'
-
-import { type Readable, type Writable, get, writable } from 'svelte/store'
+import { defaultHost, mainBranch } from '@/constants'
+import type * as Gateway from '@/gateway'
 import {
   Collection,
+  Theorems,
+  Traits,
   type Property,
   type SerializedTheorem,
   type Space,
-  Theorems,
   type Trait,
-  Traits,
-} from '../models'
+} from '@/models'
+import { read } from '@/util'
+import { get, writable, type Readable, type Writable } from 'svelte/store'
 import * as Deduction from './deduction'
 import * as Source from './source'
 import * as Sync from './sync'
-import type * as Gateway from '../gateway'
-import { read } from '../util'
+
+export { default as list } from './list'
+export { default as search } from './search'
 
 export type Meta = {
   etag?: string
@@ -42,12 +43,25 @@ export type Store = {
   deduction: Deduction.Store
 }
 
-export function create(pre: Prestore, gateway: Gateway.Sync): Store {
+export function create(
+  pre: Prestore,
+  gateway: Gateway.Sync,
+  {
+    host = defaultHost,
+    branch = mainBranch,
+  }: {
+    host?: string
+    branch?: string
+  } = {},
+): Store {
   const spaces = writable(Collection.empty<Space>())
   const properties = writable(Collection.empty<Property>())
   const theorems = writable(new Theorems())
   const traits = writable(new Traits())
-  const source = Source.create()
+  const source = Source.create({
+    host,
+    branch,
+  })
   const sync = Sync.create(refresh, pre.sync)
 
   const deduction = Deduction.create(
diff --git a/packages/viewer/src/stores/source.ts b/packages/viewer/src/stores/source.ts
index 50ef4159..6b4df224 100644
--- a/packages/viewer/src/stores/source.ts
+++ b/packages/viewer/src/stores/source.ts
@@ -1,7 +1,6 @@
 import { type Readable, writable } from 'svelte/store'
-import { bundle } from '@pi-base/core'
 
-import { mainBranch } from '../constants'
+import { defaultHost, mainBranch } from '../constants'
 import { trace } from '../debug'
 import type { Source } from '../types'
 
@@ -14,10 +13,10 @@ export interface Store extends Readable<Source> {
 
 export const initial: Source = {
   branch: mainBranch,
-  host: bundle.defaultHost,
+  host: defaultHost,
 }
 
-export function create(source?: Source): Store {
+export function create(source: Source): Store {
   const store = writable<Source>(source || initial)
 
   const { subscribe, update } = store
diff --git a/packages/viewer/vite.config.js b/packages/viewer/vite.config.js
index 7b9ea199..d265798f 100644
--- a/packages/viewer/vite.config.js
+++ b/packages/viewer/vite.config.js
@@ -1,9 +1,32 @@
 import { sveltekit } from '@sveltejs/kit/vite'
 import { defineConfig } from 'vitest/config'
+import { readFileSync } from 'node:fs'
+
+const pathExp = new RegExp('/refs/heads/(.*).json')
+
+/** @type {import('vite').Plugin} */
+const fixtures = {
+  name: 'fixtures-middleware',
+  // See https://kit.svelte.dev/docs/faq#how-do-i-use-x-with-sveltekit-how-do-i-use-middleware
+  configureServer(server) {
+    server.middlewares.use((req, res, next) => {
+      const match = pathExp.exec(req.url)
+      if (match) {
+        res.setHeader('Content-Type', 'application/json')
+
+        const ref = match[1]
+        const data = readFileSync(`./cypress/fixtures/${ref}.min.json`)
+        return res.end(data)
+      }
+
+      next()
+    })
+  },
+}
 
 // https://vitejs.dev/config/
 export default defineConfig({
-  plugins: [sveltekit()],
+  plugins: [sveltekit(), fixtures],
   test: {
     include: ['src/**/*.{test,spec}.{js,ts}'],
     coverage: {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 0ec9aec4..3996532a 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -221,8 +221,8 @@ importers:
         specifier: ^2.0.9
         version: 2.0.9
       cypress:
-        specifier: ^12.17.4
-        version: 12.17.4
+        specifier: ^13.3.3
+        version: 13.3.3
       svelte:
         specifier: ^3.59.2
         version: 3.59.2
@@ -273,8 +273,8 @@ packages:
       '@jridgewell/trace-mapping': 0.3.9
     dev: true
 
-  /@cypress/request@2.88.12:
-    resolution: {integrity: sha512-tOn+0mDZxASFM+cuAP9szGUGPI1HwWVSvdzm7V4cCsPdFTx6qMj29CwaQmRAMIEhORIUBFBsYROYJcveK4uOjA==}
+  /@cypress/request@3.0.1:
+    resolution: {integrity: sha512-TWivJlJi8ZDx2wGOw1dbLuHJKUYX7bWySw377nlnGOW3hP9/MUKIsEdXT/YngWxVdgNCHRBmFlBipE+5/2ZZlQ==}
     engines: {node: '>= 6'}
     dependencies:
       aws-sign2: 0.7.0
@@ -1218,14 +1218,16 @@ packages:
   /@types/ms@0.7.31:
     resolution: {integrity: sha512-iiUgKzV9AuaEkZqkOLDIvlQiL6ltuZd9tGcW3gwpnX8JbuiuhFlEGmmFXEXkN50Cvq7Os88IY2v0dkDqXYWVgA==}
 
-  /@types/node@16.18.59:
-    resolution: {integrity: sha512-PJ1w2cNeKUEdey4LiPra0ZuxZFOGvetswE8qHRriV/sUkL5Al4tTmPV9D2+Y/TPIxTHHgxTfRjZVKWhPw/ORhQ==}
-    dev: true
-
   /@types/node@18.16.6:
     resolution: {integrity: sha512-N7KINmeB8IN3vRR8dhgHEp+YpWvGFcpDoh5XZ8jB5a00AdFKCKEyyGTOPTddUf4JqU1ZKTVxkOxakDvchNVI2Q==}
     dev: true
 
+  /@types/node@18.18.7:
+    resolution: {integrity: sha512-bw+lEsxis6eqJYW8Ql6+yTqkE6RuFtsQPSe5JxXbqYRFQEER5aJA9a5UH9igqDWm3X4iLHIKOHlnAXLM4mi7uQ==}
+    dependencies:
+      undici-types: 5.26.5
+    dev: true
+
   /@types/node@20.1.1:
     resolution: {integrity: sha512-uKBEevTNb+l6/aCQaKVnUModfEMjAl98lw2Si9P5y4hLu9tm6AlX2ZIoXZX6Wh9lJueYPrGPKk5WMCNHg/u6/A==}
     dev: true
@@ -1288,7 +1290,7 @@ packages:
     resolution: {integrity: sha512-Cn6WYCm0tXv8p6k+A8PvbDG763EDpBoTzHdA+Q/MF6H3sapGjCm9NzoaJncJS9tUKSuCoDs9XHxYYsQDgxR6kw==}
     requiresBuild: true
     dependencies:
-      '@types/node': 18.16.6
+      '@types/node': 18.18.7
     dev: true
     optional: true
 
@@ -2005,15 +2007,15 @@ packages:
       type-fest: 1.4.0
     dev: true
 
-  /cypress@12.17.4:
-    resolution: {integrity: sha512-gAN8Pmns9MA5eCDFSDJXWKUpaL3IDd89N9TtIupjYnzLSmlpVr+ZR+vb4U/qaMp+lB6tBvAmt7504c3Z4RU5KQ==}
-    engines: {node: ^14.0.0 || ^16.0.0 || >=18.0.0}
+  /cypress@13.3.3:
+    resolution: {integrity: sha512-mbdkojHhKB1xbrj7CrKWHi22uFx9P9vQFiR0sYDZZoK99OMp9/ZYN55TO5pjbXmV7xvCJ4JwBoADXjOJK8aCJw==}
+    engines: {node: ^16.0.0 || ^18.0.0 || >=20.0.0}
     hasBin: true
     requiresBuild: true
     dependencies:
-      '@cypress/request': 2.88.12
+      '@cypress/request': 3.0.1
       '@cypress/xvfb': 1.2.4(supports-color@8.1.1)
-      '@types/node': 16.18.59
+      '@types/node': 18.18.7
       '@types/sinonjs__fake-timers': 8.1.1
       '@types/sizzle': 2.3.3
       arch: 2.2.0
@@ -5864,6 +5866,10 @@ packages:
     resolution: {integrity: sha512-WxONCrssBM8TSPRqN5EmsjVrsv4A8X12J4ArBiiayv3DyyG3ZlIg6yysuuSYdZsVz3TKcTg2fd//Ujd4CHV1iA==}
     dev: true
 
+  /undici-types@5.26.5:
+    resolution: {integrity: sha512-JlCMO+ehdEIKqlFxk6IfVoAUVmgz7cU7zD/h9XZ0qzeosSHmUJVOzSQvvYSYWXkFXC+IfLKSIffhv0sVZup6pA==}
+    dev: true
+
   /undici@5.26.5:
     resolution: {integrity: sha512-cSb4bPFd5qgR7qr2jYAi0hlX9n5YKK2ONKkLFkxl+v/9BvC0sOpZjBHDBSXc5lWAf5ty9oZdRXytBIHzgUcerw==}
     engines: {node: '>=14.0'}