diff --git a/.gitattributes b/.gitattributes
index b17d448d5..a455f6f5c 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,4 +1,4 @@
 *.res linguist-language=ReScript
 *.resi linguist-language=ReScript
 
-/public/playground-bundles/**  binary linguist-vendored
+/apps/docs/public/playground-bundles/**  binary linguist-vendored
diff --git a/.github/scripts/deployment-environment.sh b/.github/scripts/deployment-environment.sh
index 41c3f1715..79d173324 100644
--- a/.github/scripts/deployment-environment.sh
+++ b/.github/scripts/deployment-environment.sh
@@ -1,10 +1,13 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
-# Export the canonical production URL or the branch-specific Pages preview URL
-# for later GitHub Actions steps.
-if [[ "$RAW_BRANCH" == "master" ]]; then
+# Pages selects production by branch. Manual previews of master must use a
+# preview alias, while a manual production deploy must explicitly target master.
+if [[ "${GITHUB_EVENT_NAME:-}" == "push" && "$RAW_BRANCH" == "master" ]] ||
+   [[ "${GITHUB_EVENT_NAME:-}" == "workflow_dispatch" && "${DEPLOY_ENVIRONMENT:-}" == "production" ]]; then
   {
+    echo "SAFE_BRANCH=master"
+    echo "DOCS_DEPLOYMENT_ENVIRONMENT=production"
     echo "VITE_DEPLOYMENT_URL="
     echo "DOCS_DEPLOYMENT_URL=https://rescript-lang.org"
   } >> "$GITHUB_ENV"
@@ -19,6 +22,7 @@ else
   SAFE_BRANCH="${BRANCH_PREFIX}-${BRANCH_DIGEST}"
   {
     echo "SAFE_BRANCH=$SAFE_BRANCH"
+    echo "DOCS_DEPLOYMENT_ENVIRONMENT=preview"
     echo "VITE_DEPLOYMENT_URL=https://${SAFE_BRANCH}.rescript-lang.pages.dev"
     echo "DOCS_DEPLOYMENT_URL=https://${SAFE_BRANCH}.rescript-lang.pages.dev"
   } >> "$GITHUB_ENV"
diff --git a/.github/scripts/lighthouse-environment.sh b/.github/scripts/lighthouse-environment.sh
index 3bf5320f7..701c1d9c2 100644
--- a/.github/scripts/lighthouse-environment.sh
+++ b/.github/scripts/lighthouse-environment.sh
@@ -7,12 +7,14 @@ REPOSITORY_ROOT=$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)
 
 if [[ "$GITHUB_EVENT_NAME" == "pull_request" ]]; then
   RAW_TARGET_BRANCH=$(gh api "/repos/${GITHUB_REPOSITORY}/pulls/${PR_NUMBER}" --jq '.base.ref')
+  TARGET_ENVIRONMENT=""
 else
   RAW_TARGET_BRANCH="$RAW_BRANCH"
+  TARGET_ENVIRONMENT="${DOCS_DEPLOYMENT_ENVIRONMENT:-}"
 fi
 
-ARTIFACT_NAME=$(node "$REPOSITORY_ROOT/apps/docs/scripts/lighthouse-report.mjs" artifact-name "$RAW_BRANCH")
-TARGET_ARTIFACT_NAME=$(node "$REPOSITORY_ROOT/apps/docs/scripts/lighthouse-report.mjs" artifact-name "$RAW_TARGET_BRANCH")
+ARTIFACT_NAME=$(node "$REPOSITORY_ROOT/apps/docs/scripts/lighthouse-report.mjs" artifact-name "$RAW_BRANCH" "${DOCS_DEPLOYMENT_ENVIRONMENT:-}")
+TARGET_ARTIFACT_NAME=$(node "$REPOSITORY_ROOT/apps/docs/scripts/lighthouse-report.mjs" artifact-name "$RAW_TARGET_BRANCH" "$TARGET_ENVIRONMENT")
 
 {
   echo "LIGHTHOUSE_ARTIFACT_NAME=$ARTIFACT_NAME"
diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 9bd8bc6e2..7bbe3ff2c 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -6,7 +6,11 @@ on:
   workflow_dispatch:
     inputs:
       environment:
-        description: "Choose an environment to deploy to: <preview|production>"
+        description: "Deployment environment for docs and guide"
+        type: choice
+        options:
+          - preview
+          - production
         required: true
         default: "preview"
   pull_request:
@@ -41,6 +45,7 @@ jobs:
       - name: Set VITE_DEPLOYMENT_URL
         env:
           RAW_BRANCH: ${{ github.head_ref || github.ref_name }}
+          DEPLOY_ENVIRONMENT: ${{ inputs.environment }}
         shell: bash
         run: bash .github/scripts/deployment-environment.sh
       - name: Build
@@ -93,6 +98,7 @@ jobs:
       - name: Set deployment URL
         env:
           RAW_BRANCH: ${{ github.head_ref || github.ref_name }}
+          DEPLOY_ENVIRONMENT: ${{ inputs.environment }}
         shell: bash
         run: bash .github/scripts/deployment-environment.sh
       - name: Set Lighthouse environment
@@ -250,6 +256,7 @@ jobs:
       - name: Set deployment URL
         env:
           RAW_BRANCH: ${{ github.head_ref || github.ref_name }}
+          DEPLOY_ENVIRONMENT: ${{ inputs.environment }}
         shell: bash
         run: bash .github/scripts/deployment-environment.sh
       - name: Cypress E2E tests
diff --git a/.gitignore b/.gitignore
index eed8655e7..86bfbc802 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,7 +7,6 @@
 apps/docs/public/blog/feed.xml
 
 node_modules/
-.next/
 out/
 apps/docs/out/
 index_data/*.json
@@ -28,15 +27,8 @@ apps/docs/lib/
 apps/guide/lib/
 packages/*/lib/
 
-.vercel
-
-apps/docs/src/**/*.mjs
 apps/docs/src/**/*.jsx
-apps/guide/src/**/*.mjs
-apps/guide/src/**/*.jsx
-packages/*/src/**/*.mjs
 packages/*/src/**/*.jsx
-apps/docs/scripts/generate_*.mjs
 apps/docs/scripts/generate_*.jsx
 apps/docs/scripts/LogAlgoliaEnvStatus.jsx
 apps/docs/scripts/__tests__/**/*.jsx
@@ -48,38 +40,23 @@ apps/docs/public/llms/react/**/llm*.txt
 apps/docs/markdown-pages/docs/**/**/llms.mdx
 
 apps/docs/public/playground-bundles/
-!apps/docs/public/_redirects
 
-dist
 build
-apps/docs/dist
 apps/docs/build
-apps/guide/dist
 apps/guide/build
 .react-router
 apps/docs/.react-router
 apps/guide/.react-router
-mdx-manifest.json
-apps/docs/mdx-manifest.json
 
-apps/docs/app/**/*.mjs
 apps/docs/app/**/*.jsx
-apps/guide/app/**/*.mjs
 apps/guide/app/**/*.jsx
 !apps/guide/app/root.jsx
 !apps/guide/app/routes.jsx
-apps/docs/functions/**/*.mjs
 apps/docs/functions/**/*.jsx
-apps/docs/__tests__/**/*.mjs
 apps/docs/__tests__/**/*.jsx
-apps/docs/test-utils/**/*.mjs
 apps/docs/test-utils/**/*.jsx
-apps/guide/__tests__/**/*.mjs
 apps/guide/__tests__/**/*.jsx
-apps/docs/e2e/**/*.mjs
 apps/docs/e2e/**/*.jsx
-!_shims.mjs
-!_shims.jsx
 
 # Yarn
 .yarn/*
@@ -101,9 +78,6 @@ apps/docs/_scripts
 .env.local
 apps/docs/.env.local
 
-# Local git worktrees
-.worktrees
-
 # Vitest screenshots
 !apps/docs/__tests__/**/__screenshots__/**/*
 .vitest-attachments
diff --git a/.oxfmtrc.json b/.oxfmtrc.json
index 85a79c701..aade3da38 100644
--- a/.oxfmtrc.json
+++ b/.oxfmtrc.json
@@ -3,15 +3,11 @@
   "printWidth": 80,
   "sortPackageJson": false,
   "ignorePatterns": [
-    "!_shims.mjs",
-    "!apps/docs/public/_redirects",
     ".DS_Store",
     ".worktrees/",
-    ".next/",
     ".react-router",
     "*.swo",
     "*.swp",
-    "apps/docs/app/**/*.mjs",
     "apps/guide/app/**/*.jsx",
     "build",
     "data/api/**/*.json",
@@ -21,22 +17,15 @@
     "apps/docs/out/",
     "apps/docs/public/playground-bundles/",
     "apps/docs/public/blog/feed.xml",
-    "_tempFile.cmi",
-    "_tempFile.cmj",
-    "_tempFile.cmt",
-    "_tempFile.res",
     "temp",
     ".bsb.lock",
     ".merlin",
     "lib/",
     "apps/docs/lib/",
-    ".vercel",
-    "apps/docs/src/**/*.mjs",
-    "apps/docs/scripts/generate_*.mjs",
     "apps/docs/public/llms/manual/**/llm*.txt",
     "apps/docs/public/llms/react/**/llm*.txt",
     "apps/docs/markdown-pages/docs/**/**/llms.mdx",
     "apps/docs/markdown-pages/docs/manual/installation.mdx",
-    ".yarn/releases/yarn-4.12.0.cjs"
+    ".yarn/releases/*.cjs"
   ]
 }
diff --git a/Makefile b/Makefile
index 11380d35a..7079af3a3 100644
--- a/Makefile
+++ b/Makefile
@@ -19,4 +19,4 @@ clean:
 
 .DEFAULT_GOAL := build
 
-.PHONY: clean test
+.PHONY: build dev clean test
diff --git a/apps/docs/scripts/__tests__/LighthouseFixtures.res b/apps/docs/scripts/__tests__/LighthouseFixtures.res
index e0e171fad..4c2f194f4 100644
--- a/apps/docs/scripts/__tests__/LighthouseFixtures.res
+++ b/apps/docs/scripts/__tests__/LighthouseFixtures.res
@@ -27,7 +27,7 @@ type commentInput = {
 }
 
 @module("../lighthouse-report.mjs")
-external artifactName: string => string = "lighthouseArtifactName"
+external artifactName: (string, ~environment: string=?) => string = "lighthouseArtifactName"
 @module("../lighthouse-report.mjs") external median: array<float> => float = "median"
 @module("../lighthouse-report.mjs")
 external createBaseline: baselineInput => baseline = "createBaseline"
diff --git a/apps/docs/scripts/__tests__/LighthouseReport_.test.res b/apps/docs/scripts/__tests__/LighthouseReport_.test.res
index 5f4a7ab43..1ef51a79b 100644
--- a/apps/docs/scripts/__tests__/LighthouseReport_.test.res
+++ b/apps/docs/scripts/__tests__/LighthouseReport_.test.res
@@ -25,6 +25,25 @@ test("artifact-name CLI prints the same key used by the report helper", async ()
   expect(result.stdout)->toBe(`${artifactName("perf/fonts")}\n`)
 })
 
+for_([
+  ("master", "preview"),
+  ("perf/homepage", "production"),
+])("artifact-name CLI separates %s baselines in %s", async ((branch, deploymentEnvironment)) => {
+  let state = await workspace()
+  let result = run(state, ["artifact-name", branch, deploymentEnvironment], ())
+  expectSuccess(result)
+  let artifact = artifactName(branch, ~environment=deploymentEnvironment)
+  expect(result.stdout)->toBe(`${artifact}\n`)
+  expect(artifact != artifactName(branch))->toBe(true)
+})
+
+test("artifact-name CLI rejects an invalid environment", async () => {
+  let state = await workspace()
+  let result = run(state, ["artifact-name", "master", "staging"], ())
+  expectStatus(result, 1)
+  expect(result.stderr)->toContain("Invalid Lighthouse deployment environment: staging")
+})
+
 for_([[], [""]])("artifact-name CLI rejects missing or empty branch %j", async arguments => {
   let state = await workspace()
   let result = run(state, ["artifact-name", ...arguments], ())
diff --git a/apps/docs/scripts/__tests__/LighthouseWorkflowFixtures.res b/apps/docs/scripts/__tests__/LighthouseWorkflowFixtures.res
index 4853409d8..50dd575e0 100644
--- a/apps/docs/scripts/__tests__/LighthouseWorkflowFixtures.res
+++ b/apps/docs/scripts/__tests__/LighthouseWorkflowFixtures.res
@@ -62,6 +62,8 @@ let fixture = async (~overrides=[], ()) => {
         ("CALLS", join([directory, "calls.jsonl"])),
         ("GITHUB_ENV", join([directory, "environment"])),
         ("GITHUB_EVENT_NAME", "pull_request"),
+        ("DEPLOY_ENVIRONMENT", ""),
+        ("DOCS_DEPLOYMENT_ENVIRONMENT", ""),
         ("GITHUB_REPOSITORY", "owner/site"),
         ("PR_NUMBER", "1355"),
         ("RAW_BRANCH", "Perf/Homepage"),
diff --git a/apps/docs/scripts/__tests__/LighthouseWorkflow_.test.res b/apps/docs/scripts/__tests__/LighthouseWorkflow_.test.res
index 749da9848..7c8ec1bbf 100644
--- a/apps/docs/scripts/__tests__/LighthouseWorkflow_.test.res
+++ b/apps/docs/scripts/__tests__/LighthouseWorkflow_.test.res
@@ -28,23 +28,74 @@ test("production uses its own baseline without a PR lookup", async () => {
   expect(exists(join([state.directory, "calls.jsonl"])))->toBe(false)
 })
 
+test("preview PR audits compare against the target branch's default environment", async () => {
+  let state = await Workflow.fixture(
+    ~overrides=[("GH_RESPONSE", "master\n"), ("DOCS_DEPLOYMENT_ENVIRONMENT", "preview")],
+    (),
+  )
+  expectSuccess(Workflow.run("lighthouse-environment.sh", state))
+  let environment = await Workflow.environmentContents(state)
+  expect(environment)->toContain(
+    `LIGHTHOUSE_TARGET_ARTIFACT_NAME=${LighthouseFixtures.artifactName("master")}\n`,
+  )
+  expect(environment)->toContain("LIGHTHOUSE_TARGET_BRANCH=master\n")
+})
+
+let productionEnvironment = "SAFE_BRANCH=master\nDOCS_DEPLOYMENT_ENVIRONMENT=production\nVITE_DEPLOYMENT_URL=\nDOCS_DEPLOYMENT_URL=https://rescript-lang.org\n"
+let homepagePreviewEnvironment = "SAFE_BRANCH=perf-homepage-19ab1c0e\nDOCS_DEPLOYMENT_ENVIRONMENT=preview\nVITE_DEPLOYMENT_URL=https://perf-homepage-19ab1c0e.rescript-lang.pages.dev\nDOCS_DEPLOYMENT_URL=https://perf-homepage-19ab1c0e.rescript-lang.pages.dev\n"
+let masterPreviewEnvironment = "SAFE_BRANCH=master-fc613b4d\nDOCS_DEPLOYMENT_ENVIRONMENT=preview\nVITE_DEPLOYMENT_URL=https://master-fc613b4d.rescript-lang.pages.dev\nDOCS_DEPLOYMENT_URL=https://master-fc613b4d.rescript-lang.pages.dev\n"
+
 for_([
-  ("master", "VITE_DEPLOYMENT_URL=\n", "DOCS_DEPLOYMENT_URL=https://rescript-lang.org\n"),
-  (
-    "Perf/Homepage",
-    "VITE_DEPLOYMENT_URL=https://perf-homepage-19ab1c0e.rescript-lang.pages.dev\n",
-    "DOCS_DEPLOYMENT_URL=https://perf-homepage-19ab1c0e.rescript-lang.pages.dev\n",
-  ),
-])("deployment environment for %s does not depend on GitHub artifact access", async ((
+  ("master", "preview"),
+  ("Perf/Homepage", "production"),
+])("manual Lighthouse baselines for %s in %s stay separate from the default environment", async ((
   branch,
-  expectedViteUrl,
-  expectedDocsUrl,
+  deploymentEnvironment,
 )) => {
-  let state = await Workflow.fixture(~overrides=[("RAW_BRANCH", branch), ("GH_FAIL", "1")], ())
-  expectSuccess(Workflow.run("deployment-environment.sh", state))
+  let state = await Workflow.fixture(
+    ~overrides=[
+      ("GITHUB_EVENT_NAME", "workflow_dispatch"),
+      ("RAW_BRANCH", branch),
+      ("DOCS_DEPLOYMENT_ENVIRONMENT", deploymentEnvironment),
+      ("GH_FAIL", "1"),
+    ],
+    (),
+  )
+  expectSuccess(Workflow.run("lighthouse-environment.sh", state))
   let environment = await Workflow.environmentContents(state)
-  expect(environment)->toContain(expectedViteUrl)
-  expect(environment)->toContain(expectedDocsUrl)
+  let artifact = LighthouseFixtures.artifactName(branch, ~environment=deploymentEnvironment)
+  expect(artifact != LighthouseFixtures.artifactName(branch))->toBe(true)
+  expect(environment)->toContain(`LIGHTHOUSE_ARTIFACT_NAME=${artifact}\n`)
+  expect(environment)->toContain(`LIGHTHOUSE_TARGET_ARTIFACT_NAME=${artifact}\n`)
+  expect(environment)->toContain(`LIGHTHOUSE_BRANCH=${branch}\n`)
+  expect(exists(join([state.directory, "calls.jsonl"])))->toBe(false)
+})
+
+for_([
+  ("push", "master", "", productionEnvironment),
+  ("pull_request", "Perf/Homepage", "", homepagePreviewEnvironment),
+  ("pull_request", "master", "", masterPreviewEnvironment),
+  ("workflow_dispatch", "master", "preview", masterPreviewEnvironment),
+  ("workflow_dispatch", "Perf/Homepage", "preview", homepagePreviewEnvironment),
+  ("workflow_dispatch", "master", "production", productionEnvironment),
+  ("workflow_dispatch", "Perf/Homepage", "production", productionEnvironment),
+])("deployment environment for %s on %s with selection '%s'", async ((
+  event,
+  branch,
+  selection,
+  expectedEnvironment,
+)) => {
+  let state = await Workflow.fixture(
+    ~overrides=[
+      ("GITHUB_EVENT_NAME", event),
+      ("RAW_BRANCH", branch),
+      ("DEPLOY_ENVIRONMENT", selection),
+      ("GH_FAIL", "1"),
+    ],
+    (),
+  )
+  expectSuccess(Workflow.run("deployment-environment.sh", state))
+  expect(await Workflow.environmentContents(state))->toBe(expectedEnvironment)
   expect(exists(join([state.directory, "calls.jsonl"])))->toBe(false)
 })
 
diff --git a/apps/docs/scripts/lighthouse-report.mjs b/apps/docs/scripts/lighthouse-report.mjs
index fea5129cb..15d5e2150 100644
--- a/apps/docs/scripts/lighthouse-report.mjs
+++ b/apps/docs/scripts/lighthouse-report.mjs
@@ -17,16 +17,32 @@ const reportCategoryKeys = {
   seo: "seo",
 };
 
-export function lighthouseArtifactName(branch) {
+export function lighthouseArtifactName(branch, environment) {
+  const defaultEnvironment = branch === "master" ? "production" : "preview";
+  const effectiveEnvironment = environment || defaultEnvironment;
+  if (!["production", "preview"].includes(effectiveEnvironment)) {
+    throw new Error(
+      `Invalid Lighthouse deployment environment: ${effectiveEnvironment}`,
+    );
+  }
+  // Preserve existing production-master and branch-preview keys. Alternative
+  // environments use a separate identity so they cannot overwrite those keys.
+  const isDefaultEnvironment = effectiveEnvironment === defaultEnvironment;
+  const identity = isDefaultEnvironment
+    ? branch
+    : `${effectiveEnvironment}\0${branch}`;
+  const environmentPrefix = isDefaultEnvironment
+    ? ""
+    : `${effectiveEnvironment}-`;
   const slug = branch
     .toLowerCase()
     .replace(/[^a-z0-9-]+/g, "-")
     .replace(/^-+|-+$/g, "")
     .replace(/-+/g, "-")
     .slice(0, 80);
-  const digest = createHash("sha256").update(branch, "utf8").digest("hex");
+  const digest = createHash("sha256").update(identity, "utf8").digest("hex");
 
-  return `homepage-lighthouse-${slug || "branch"}-${digest}`;
+  return `homepage-lighthouse-${environmentPrefix}${slug || "branch"}-${digest}`;
 }
 
 function getFiniteNumber(value, description) {
@@ -224,13 +240,13 @@ async function writeComment() {
   );
 }
 
-async function main(command, branch) {
+async function main(command, branch, environment) {
   if (command === "artifact-name") {
     if (!branch) {
       throw new Error("A branch name is required for artifact-name");
     }
 
-    console.log(lighthouseArtifactName(branch));
+    console.log(lighthouseArtifactName(branch, environment));
     return;
   }
 
@@ -252,5 +268,5 @@ const entryPath = process.argv[1]
   : "";
 
 if (import.meta.url === entryPath) {
-  await main(process.argv[2], process.argv[3]);
+  await main(process.argv[2], process.argv[3], process.argv[4]);
 }