diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e30a5cc22c..0ef16299fa 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,10 +2,10 @@ name: CI
 
 on:
   push:
-    branches: [master, 11.0_release]
+    branches: [master, maintenance/*]
 
   pull_request:
-    branches: [master, 11.0_release]
+    branches: [master, maintenance/*]
 
   # Release builds are started by publish.yml after a maintainer indicates
   # whether the package version is current stable. The npm tag is derived from
@@ -32,6 +32,7 @@ jobs:
   build-compiler:
     outputs:
       api-docs-artifact-id: ${{ steps.upload-api-docs.outputs.artifact-id }}
+      website-branch: ${{ steps.api-docs-plan.outputs.website-branch }}
     strategy:
       fail-fast: false
       matrix:
@@ -381,6 +382,11 @@ jobs:
             !packages/@rescript/runtime/lib/ocaml/*.ast
             !packages/@rescript/runtime/lib/ocaml/*.iast
 
+      - name: Select API docs website branch
+        id: api-docs-plan
+        if: ${{ matrix.generate_api_docs }}
+        run: node scripts/releasePlan.js --github-output "$GITHUB_OUTPUT"
+
       - name: Generate API Docs
         if: ${{ matrix.generate_api_docs }}
         run: yarn apidocs:generate
@@ -488,6 +494,7 @@ jobs:
         uses: actions/checkout@v7
         with:
           repository: rescript-lang/rescript-lang.org
+          ref: ${{ needs.build-compiler.outputs.website-branch }}
 
       - name: Download artifacts
         uses: actions/download-artifact@v8
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index e42924a2a7..fb3be6c787 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -19,6 +19,7 @@ jobs:
       version: ${{ steps.plan.outputs.version }}
       npm-tag: ${{ steps.plan.outputs.npm-tag }}
       publish-tag: ${{ steps.plan.outputs.publish-tag }}
+      website-branch: ${{ steps.plan.outputs.website-branch }}
     steps:
       - name: Checkout
         uses: actions/checkout@v7
@@ -156,6 +157,7 @@ jobs:
         uses: actions/checkout@v7
         with:
           repository: rescript-lang/rescript-lang.org
+          ref: ${{ needs.release-plan.outputs.website-branch }}
           path: rescript-lang.org
           ssh-key: ${{ secrets.RESCRIPT_LANG_ORG_DEPLOY_KEY }}
 
@@ -194,12 +196,16 @@ jobs:
 
       - name: Publish API docs
         if: steps.api-docs-diff.outputs.changed == 'true'
+        env:
+          WEBSITE_BRANCH: ${{ needs.release-plan.outputs.website-branch }}
         run: |
           git config user.name "github-actions[bot]"
           git config user.email "github-actions@rescript-lang.org"
           git add data/api
           git commit -m "Update API docs for v${{ needs.release-plan.outputs.version }}"
-          git push
+          # The deploy key lets this push trigger the website branch's
+          # deployment workflow.
+          git push origin "HEAD:$WEBSITE_BRANCH"
         working-directory: rescript-lang.org
 
       - name: Update Website Playground
diff --git a/changes/versioned-api-docs.internal.md b/changes/versioned-api-docs.internal.md
new file mode 100644
index 0000000000..e3c3823f82
--- /dev/null
+++ b/changes/versioned-api-docs.internal.md
@@ -0,0 +1,3 @@
+- Route API documentation checks and publication to the website branch matching
+  the compiler major (`v12`, `v13`, and later), keeping the target unchanged when
+  a release becomes current stable or moves to a maintenance branch.
diff --git a/scripts/releasePlan.js b/scripts/releasePlan.js
index 058d69f88c..f2e1267e97 100644
--- a/scripts/releasePlan.js
+++ b/scripts/releasePlan.js
@@ -3,6 +3,7 @@
 import fs from "node:fs/promises";
 import path from "node:path";
 import process from "node:process";
+import { fileURLToPath } from "node:url";
 import { parseArgs } from "node:util";
 import semver from "semver";
 
@@ -36,6 +37,7 @@ export function createReleasePlan(version, currentStable = false) {
     currentStable,
     npmTag,
     publishTag: currentStable ? null : npmTag,
+    websiteBranch: `v${parsedVersion.major}`,
   };
 }
 
@@ -112,6 +114,7 @@ async function main() {
       `git-tag=${plan.gitTag}`,
       `npm-tag=${plan.npmTag}`,
       `publish-tag=${plan.publishTag ?? ""}`,
+      `website-branch=${plan.websiteBranch}`,
     ].join("\n");
     await fs.appendFile(values["github-output"], `${output}\n`);
   }
@@ -125,6 +128,7 @@ async function main() {
       `| Version | \`${plan.version}\` |`,
       `| Git tag | \`${plan.gitTag}\` |`,
       `| npm tag | \`${plan.npmTag}\` |`,
+      `| Website branch | \`${plan.websiteBranch}\` |`,
       `| Source commit | \`${process.env.GITHUB_SHA ?? "local"}\` |`,
       "",
       "The protected `npm-release` job publishes this plan after approval.",
@@ -136,7 +140,10 @@ async function main() {
   console.log(JSON.stringify(plan, null, 2));
 }
 
-if (import.meta.url === `file://${process.argv[1]}`) {
+if (
+  process.argv[1] &&
+  path.resolve(process.argv[1]) === fileURLToPath(import.meta.url)
+) {
   main().catch(error => {
     console.error(error.message || error);
     process.exitCode = 1;
diff --git a/scripts/releasePlan.test.js b/scripts/releasePlan.test.js
index 18b01d168c..41d244b652 100644
--- a/scripts/releasePlan.test.js
+++ b/scripts/releasePlan.test.js
@@ -1,14 +1,26 @@
 import assert from "node:assert/strict";
+import { spawnSync } from "node:child_process";
 import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
 import test from "node:test";
+import { fileURLToPath } from "node:url";
 import {
   createReleasePlan,
   findFirstReleasedVersion,
   findPendingFragments,
 } from "./releasePlan.js";
 
+const websiteTargets = [
+  ["12.3.1", "v12"],
+  ["12.4.0-alpha.1", "v12"],
+  ["13.0.0-alpha.7", "v13"],
+  ["13.0.0", "v13"],
+  ["13.0.1", "v13"],
+  ["14.0.0-alpha.1", "v14"],
+  ["14.0.0", "v14"],
+];
+
 test("plans a maintenance release", () => {
   assert.deepEqual(createReleasePlan("12.3.0"), {
     version: "12.3.0",
@@ -16,6 +28,7 @@ test("plans a maintenance release", () => {
     currentStable: false,
     npmTag: "latest-12",
     publishTag: "latest-12",
+    websiteBranch: "v12",
   });
 });
 
@@ -23,6 +36,7 @@ test("plans a current stable release", () => {
   const plan = createReleasePlan("13.0.0", true);
   assert.equal(plan.npmTag, "latest");
   assert.equal(plan.publishTag, null);
+  assert.equal(plan.websiteBranch, "v13");
 });
 
 test("derives the prerelease tag", () => {
@@ -33,6 +47,100 @@ test("derives the prerelease tag for an older major", () => {
   assert.equal(createReleasePlan("12.4.0-beta.1").npmTag, "next-12");
 });
 
+test("routes stable and prerelease API docs by compiler major", () => {
+  for (const [version, branch] of websiteTargets) {
+    assert.equal(createReleasePlan(version).websiteBranch, branch);
+  }
+});
+
+test("promoting a release changes its npm tag without moving its docs", () => {
+  for (const [version, branch] of websiteTargets) {
+    if (version.includes("-")) continue;
+    const maintenance = createReleasePlan(version);
+    const stable = createReleasePlan(version, true);
+    assert.notEqual(maintenance.npmTag, stable.npmTag);
+    assert.equal(maintenance.websiteBranch, branch);
+    assert.equal(stable.websiteBranch, branch);
+  }
+});
+
+test("exports the selected website branch for release workflows", async t => {
+  const root = await fs.mkdtemp(path.join(os.tmpdir(), "rescript-api-docs-"));
+  t.after(() => fs.rm(root, { recursive: true, force: true }));
+  const script = fileURLToPath(new URL("./releasePlan.js", import.meta.url));
+
+  for (const [version, branch] of websiteTargets) {
+    const output = path.join(root, `${version}.output`);
+    const summary = path.join(root, `${version}.summary`);
+    const result = spawnSync(
+      process.execPath,
+      [
+        script,
+        "--version",
+        version,
+        "--github-output",
+        output,
+        "--github-summary",
+        summary,
+      ],
+      { encoding: "utf8" },
+    );
+    assert.equal(result.status, 0, result.stderr);
+    assert.ok(
+      (await fs.readFile(output, "utf8")).includes(
+        `website-branch=${branch}\n`,
+      ),
+    );
+    assert.ok(
+      (await fs.readFile(summary, "utf8")).includes(
+        `| Website branch | \`${branch}\` |`,
+      ),
+    );
+  }
+});
+
+test("keeps CI routing when master advances and a maintenance branch is cut", async t => {
+  const root = await fs.mkdtemp(path.join(os.tmpdir(), "rescript-api-docs-"));
+  t.after(() => fs.rm(root, { recursive: true, force: true }));
+  const cases = [
+    ["maintenance/12.x", "12.3.1", "v12"],
+    ["master", "13.0.0-alpha.7", "v13"],
+    ["maintenance/13.x", "13.0.1", "v13"],
+    ["master", "14.0.0-alpha.1", "v14"],
+  ];
+  for (const [index, [ref, version, branch]] of cases.entries()) {
+    await fs.writeFile(
+      path.join(root, "package.json"),
+      JSON.stringify({ version }),
+    );
+    const output = path.join(root, `github-output-${index}`);
+    const result = spawnSync(
+      process.execPath,
+      [
+        fileURLToPath(new URL("./releasePlan.js", import.meta.url)),
+        "--github-output",
+        output,
+      ],
+      {
+        cwd: root,
+        encoding: "utf8",
+        env: {
+          ...process.env,
+          GITHUB_REF: `refs/heads/${ref}`,
+          GITHUB_REF_NAME: ref,
+        },
+      },
+    );
+    assert.equal(result.status, 0, result.stderr);
+    assert.ok(
+      (await fs.readFile(output, "utf8")).includes(
+        `website-branch=${branch}\n`,
+      ),
+      `${ref} at ${version} should use ${branch}`,
+    );
+  }
+});
+
 test("rejects promoting a prerelease to current stable", () => {
   assert.throws(
     () => createReleasePlan("13.0.0-alpha.6", true),