diff --git a/app/assets/javascripts/discourse/app/lib/load-oneboxes.js b/app/assets/javascripts/discourse/app/lib/load-oneboxes.js
index 29ced7b5919..0be10658ecf 100644
--- a/app/assets/javascripts/discourse/app/lib/load-oneboxes.js
+++ b/app/assets/javascripts/discourse/app/lib/load-oneboxes.js
@@ -23,19 +23,20 @@ export function loadOneboxes(
   container
     .querySelectorAll(`a.onebox, a.inline-onebox-loading`)
     .forEach((link) => {
-      const text = link.textContent;
-      const isInline = link.getAttribute("class") === "inline-onebox-loading";
-      const m = isInline ? inlineOneboxes : oneboxes;
+      const isInline = link.classList.contains("inline-onebox-loading");
+
+      // maps URLs to their link elements
+      const map = isInline ? inlineOneboxes : oneboxes;
 
       if (loadedOneboxes < maxOneboxes) {
-        if (m[text] === undefined) {
-          m[text] = [];
+        if (map[link.href] === undefined) {
+          map[link.href] = [];
           loadedOneboxes++;
         }
-        m[text].push(link);
+        map[link.href].push(link);
       } else {
-        if (m[text] !== undefined) {
-          m[text].push(link);
+        if (map[link.href] !== undefined) {
+          map[link.href].push(link);
         } else if (isInline) {
           link.classList.remove("inline-onebox-loading");
         }
diff --git a/app/assets/javascripts/discourse/tests/acceptance/composer-onebox-test.js b/app/assets/javascripts/discourse/tests/acceptance/composer-onebox-test.js
index 04ad220536d..cc8ea8eecef 100644
--- a/app/assets/javascripts/discourse/tests/acceptance/composer-onebox-test.js
+++ b/app/assets/javascripts/discourse/tests/acceptance/composer-onebox-test.js
@@ -41,3 +41,42 @@ This is another test <a href=\"http://www.example.com/has-title.html\" class=\"i
     );
   });
 });
+
+acceptance("Composer - Inline Onebox", function (needs) {
+  needs.user();
+  needs.settings({
+    max_oneboxes_per_post: 2,
+    enable_markdown_linkify: true,
+    markdown_linkify_tlds: "com",
+  });
+
+  let requestsCount;
+
+  needs.pretender((server, helper) => {
+    server.get("/inline-onebox", () => {
+      ++requestsCount;
+      return helper.response({ "inline-oneboxes": [] });
+    });
+  });
+
+  test("Uses cached inline onebox", async function (assert) {
+    requestsCount = 0;
+
+    await visit("/t/internationalization-localization/280");
+    await click("#topic-footer-buttons .btn.create");
+
+    await fillIn(".d-editor-input", `Test www.example.com/page`);
+    assert.equal(requestsCount, 1);
+    assert.equal(
+      queryAll(".d-editor-preview").html().trim(),
+      '<p>Test <a href="http://www.example.com/page" class="inline-onebox-loading">www.example.com/page</a></p>'
+    );
+
+    await fillIn(".d-editor-input", `Test www.example.com/page Test`);
+    assert.equal(requestsCount, 1);
+    assert.equal(
+      queryAll(".d-editor-preview").html().trim(),
+      '<p>Test <a href="http://www.example.com/page">www.example.com/page</a> Test</p>'
+    );
+  });
+});
diff --git a/app/assets/javascripts/pretty-text/addon/inline-oneboxer.js b/app/assets/javascripts/pretty-text/addon/inline-oneboxer.js
index cbed77dd4f9..010b6a9f064 100644
--- a/app/assets/javascripts/pretty-text/addon/inline-oneboxer.js
+++ b/app/assets/javascripts/pretty-text/addon/inline-oneboxer.js
@@ -3,14 +3,20 @@ const _cache = {};
 export function applyInlineOneboxes(inline, ajax, opts) {
   opts = opts || {};
 
-  Object.keys(inline).forEach((url) => {
+  const urls = Object.keys(inline).filter((url) => !_cache[url]);
+
+  urls.forEach((url) => {
     // cache a blank locally, so we never trigger a lookup
     _cache[url] = {};
   });
 
-  return ajax("/inline-onebox", {
+  if (urls.length === 0) {
+    return;
+  }
+
+  ajax("/inline-onebox", {
     data: {
-      urls: Object.keys(inline),
+      urls,
       category_id: opts.categoryId,
       topic_id: opts.topicId,
     },