diff --git a/index.js b/index.js
index 963a5d8..75312d3 100644
--- a/index.js
+++ b/index.js
@@ -9,7 +9,7 @@ import { dashboardController } from "./lib/controllers/dashboard.js";
 import { followersController } from "./lib/controllers/followers.js";
 import { followingController } from "./lib/controllers/following.js";
 import { activitiesController } from "./lib/controllers/activities.js";
-import { migrateGetController, migratePostController } from "./lib/controllers/migrate.js";
+import { migrateGetController, migratePostController, migrateImportController } from "./lib/controllers/migrate.js";
 
 const defaults = {
   mountPath: "/activitypub",
@@ -179,7 +179,8 @@ export default class ActivityPubEndpoint {
     router.get("/admin/following", followingController(mp));
     router.get("/admin/activities", activitiesController(mp));
     router.get("/admin/migrate", migrateGetController(mp, this.options));
-    router.post("/admin/migrate", express.urlencoded({ extended: true, limit: "5mb" }), migratePostController(mp, this.options));
+    router.post("/admin/migrate", migratePostController(mp, this.options));
+    router.post("/admin/migrate/import", express.json({ limit: "5mb" }), migrateImportController(mp, this.options));
 
     return router;
   }
diff --git a/lib/controllers/migrate.js b/lib/controllers/migrate.js
index 1677279..3f36296 100644
--- a/lib/controllers/migrate.js
+++ b/lib/controllers/migrate.js
@@ -2,7 +2,8 @@
  * Migration controller — handles Mastodon account migration UI.
  *
  * GET: shows the 3-step migration page
- * POST: processes alias update or CSV file import
+ * POST /admin/migrate: alias update (small form POST)
+ * POST /admin/migrate/import: CSV import (JSON via fetch, bypasses body size limit)
  */
 
 import {
@@ -30,86 +31,16 @@ export function migrateGetController(mountPath, pluginOptions) {
 export function migratePostController(mountPath, pluginOptions) {
   return async (request, response, next) => {
     try {
-      const { application } = request.app.locals;
-      const action = request.body.action;
       let result = null;
 
-      if (action === "alias") {
-        // Update alsoKnownAs on the actor config
-        const aliasUrl = request.body.aliasUrl?.trim();
-        if (aliasUrl) {
-          pluginOptions.alsoKnownAs = aliasUrl;
-          result = {
-            type: "success",
-            text: response.locals.__("activitypub.migrate.aliasSuccess"),
-          };
-        }
-      }
-
-      if (action === "import") {
-        const followingCollection =
-          application?.collections?.get("ap_following");
-        const followersCollection =
-          application?.collections?.get("ap_followers");
-
-        const importFollowing = request.body.importTypes?.includes("following");
-        const importFollowers = request.body.importTypes?.includes("followers");
-
-        // Read file content (submitted as text via client-side FileReader)
-        const fileContent = request.body.csvContent?.trim();
-        if (!fileContent) {
-          result = {
-            type: "error",
-            text: response.locals.__("activitypub.migrate.errorNoFile"),
-          };
-        } else {
-          let followingResult = { imported: 0, failed: 0, errors: [] };
-          let followersResult = { imported: 0, failed: 0, errors: [] };
-
-          if (importFollowing && followingCollection) {
-            const handles = parseMastodonFollowingCsv(fileContent);
-            console.log(`[ActivityPub] Migration: parsed ${handles.length} following handles from CSV`);
-            followingResult = await bulkImportFollowing(
-              handles,
-              followingCollection,
-            );
-          }
-
-          if (importFollowers && followersCollection) {
-            const entries = parseMastodonFollowersList(fileContent);
-            console.log(`[ActivityPub] Migration: parsed ${entries.length} follower entries from CSV`);
-            followersResult = await bulkImportFollowers(
-              entries,
-              followersCollection,
-            );
-          }
-
-          const totalFailed =
-            followingResult.failed + followersResult.failed;
-          const allErrors = [
-            ...followingResult.errors,
-            ...followersResult.errors,
-          ];
-
-          let text = response.locals
-            .__("activitypub.migrate.success")
-            .replace("%d", followingResult.imported)
-            .replace("%d", followersResult.imported)
-            .replace("%d", totalFailed);
-
-          if (allErrors.length > 0) {
-            text += " " + response.locals
-              .__("activitypub.migrate.failedList")
-              .replace("%s", allErrors.join(", "));
-          }
-
-          result = {
-            type: totalFailed > 0 && followingResult.imported + followersResult.imported === 0
-              ? "error"
-              : "success",
-            text,
-          };
-        }
+      // Only handles alias updates (small payload, regular form POST)
+      const aliasUrl = request.body.aliasUrl?.trim();
+      if (aliasUrl) {
+        pluginOptions.alsoKnownAs = aliasUrl;
+        result = {
+          type: "success",
+          text: response.locals.__("activitypub.migrate.aliasSuccess"),
+        };
       }
 
       response.render("activitypub-migrate", {
@@ -124,3 +55,63 @@ export function migratePostController(mountPath, pluginOptions) {
   };
 }
 
+/**
+ * JSON endpoint for CSV import — receives { csvContent, importTypes }
+ * via fetch() to bypass Express's app-level urlencoded body size limit.
+ */
+export function migrateImportController(mountPath, pluginOptions) {
+  return async (request, response, next) => {
+    try {
+      const { application } = request.app.locals;
+      const { csvContent, importTypes } = request.body;
+
+      if (!csvContent?.trim()) {
+        return response.status(400).json({
+          type: "error",
+          text: "No CSV content provided.",
+        });
+      }
+
+      const followingCollection =
+        application?.collections?.get("ap_following");
+      const followersCollection =
+        application?.collections?.get("ap_followers");
+
+      const importFollowing = importTypes?.includes("following");
+      const importFollowers = importTypes?.includes("followers");
+
+      let followingResult = { imported: 0, failed: 0, errors: [] };
+      let followersResult = { imported: 0, failed: 0, errors: [] };
+
+      if (importFollowing && followingCollection) {
+        const handles = parseMastodonFollowingCsv(csvContent);
+        console.log(`[ActivityPub] Migration: parsed ${handles.length} following handles from CSV`);
+        followingResult = await bulkImportFollowing(handles, followingCollection);
+      }
+
+      if (importFollowers && followersCollection) {
+        const entries = parseMastodonFollowersList(csvContent);
+        console.log(`[ActivityPub] Migration: parsed ${entries.length} follower entries from CSV`);
+        followersResult = await bulkImportFollowers(entries, followersCollection);
+      }
+
+      const totalFailed = followingResult.failed + followersResult.failed;
+      const totalImported = followingResult.imported + followersResult.imported;
+      const allErrors = [...followingResult.errors, ...followersResult.errors];
+
+      return response.json({
+        type: totalFailed > 0 && totalImported === 0 ? "error" : "success",
+        followingImported: followingResult.imported,
+        followersImported: followersResult.imported,
+        failed: totalFailed,
+        errors: allErrors,
+      });
+    } catch (error) {
+      console.error("[ActivityPub] Migration import error:", error.message);
+      return response.status(500).json({
+        type: "error",
+        text: error.message,
+      });
+    }
+  };
+}
diff --git a/locales/en.json b/locales/en.json
index dc96b12..b2ed946 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -44,6 +44,7 @@
       "errorNoFile": "Please select a CSV file before importing.",
       "success": "Imported %d following, %d followers (%d failed).",
       "failedList": "Could not resolve: %s",
+      "failedListSummary": "Failed handles",
       "aliasSuccess": "Alias saved — your actor document now includes this account as alsoKnownAs."
     }
   }
diff --git a/package.json b/package.json
index a180233..28247e4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@rmdes/indiekit-endpoint-activitypub",
-  "version": "0.1.8",
+  "version": "0.1.9",
   "description": "ActivityPub federation endpoint for Indiekit via Fedify. Adds full fediverse support: actor, inbox, outbox, followers, following, syndication, and Mastodon migration.",
   "keywords": [
     "indiekit",
diff --git a/views/activitypub-migrate.njk b/views/activitypub-migrate.njk
index c103e1d..39c1f23 100644
--- a/views/activitypub-migrate.njk
+++ b/views/activitypub-migrate.njk
@@ -47,9 +47,7 @@
   {{ heading({ text: __("activitypub.migrate.step2Title"), level: 2 }) }}
   {{ prose({ text: __("activitypub.migrate.step2Desc") }) }}
 
-  <form method="post" novalidate x-data="csvImport()">
-    <input type="hidden" name="action" value="import">
-    <input type="hidden" name="csvContent" :value="csvContent">
+  <div x-data="csvImport('{{ mountPath }}')">
 
     {{ checkboxes({
       name: "importTypes",
@@ -86,8 +84,31 @@
       </template>
     </div>
 
-    {{ button({ text: __("activitypub.migrate.importButton") }) }}
-  </form>
+    <button class="button" type="button"
+            :disabled="importing || !csvContent"
+            @click="startImport()">
+      <span x-show="!importing">{{ __("activitypub.migrate.importButton") }}</span>
+      <span x-show="importing" x-text="statusText"></span>
+    </button>
+
+    {# Result notification #}
+    <template x-if="resultType">
+      <div :class="'notification-banner notification-banner--' + resultType"
+           role="alert" style="margin-top: 1em">
+        <p x-text="resultText"></p>
+        <template x-if="resultErrors.length > 0">
+          <details style="margin-top: 0.5em">
+            <summary>{{ __("activitypub.migrate.failedListSummary") }} (<span x-text="resultErrors.length"></span>)</summary>
+            <ul style="margin-top: 0.5em; font-size: 0.875em">
+              <template x-for="err in resultErrors" :key="err">
+                <li x-text="err"></li>
+              </template>
+            </ul>
+          </details>
+        </template>
+      </div>
+    </template>
+  </div>
 
   <hr>
 
@@ -96,12 +117,17 @@
   {{ prose({ text: __("activitypub.migrate.step3Desc") }) }}
 
   <script>
-  function csvImport() {
+  function csvImport(mountPath) {
     return {
       csvContent: '',
       fileName: '',
       lineCount: 0,
       fileError: '',
+      importing: false,
+      statusText: '',
+      resultType: '',
+      resultText: '',
+      resultErrors: [],
 
       readFile(event) {
         var self = this;
@@ -109,6 +135,9 @@
         self.fileName = '';
         self.lineCount = 0;
         self.fileError = '';
+        self.resultType = '';
+        self.resultText = '';
+        self.resultErrors = [];
 
         var file = event.target.files[0];
         if (!file) return;
@@ -130,6 +159,58 @@
           self.fileError = 'Could not read file';
         };
         reader.readAsText(file);
+      },
+
+      async startImport() {
+        var self = this;
+        self.importing = true;
+        self.resultType = '';
+        self.resultText = '';
+        self.resultErrors = [];
+        self.statusText = 'Importing\u2026';
+
+        // Collect checked import types
+        var checkboxes = document.querySelectorAll('input[name="importTypes"]:checked');
+        var importTypes = [];
+        for (var i = 0; i < checkboxes.length; i++) {
+          importTypes.push(checkboxes[i].value);
+        }
+
+        if (importTypes.length === 0) {
+          self.importing = false;
+          self.resultType = 'error';
+          self.resultText = 'Please select at least one import type.';
+          return;
+        }
+
+        try {
+          var res = await fetch(mountPath + '/admin/migrate/import', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+              csvContent: self.csvContent,
+              importTypes: importTypes
+            })
+          });
+
+          if (!res.ok) {
+            var errBody = await res.text();
+            throw new Error('Server error (' + res.status + '): ' + errBody);
+          }
+
+          var data = await res.json();
+          self.resultType = data.type;
+          self.resultText = 'Imported ' + (data.followingImported || 0) + ' following, '
+            + (data.followersImported || 0) + ' followers'
+            + (data.failed > 0 ? ' (' + data.failed + ' failed)' : '') + '.';
+          self.resultErrors = data.errors || [];
+        } catch (err) {
+          self.resultType = 'error';
+          self.resultText = err.message;
+        }
+
+        self.importing = false;
+        self.statusText = '';
       }
     };
   }