diff --git a/ext/bg/css/settings.css b/ext/bg/css/settings.css
index 63cead6b..815a88fa 100644
--- a/ext/bg/css/settings.css
+++ b/ext/bg/css/settings.css
@@ -187,6 +187,23 @@ input[type=checkbox].storage-button-checkbox {
     margin: 0;
 }
 
+.error-data-show-button {
+    display: inline-block;
+    margin-left: 0.5em;
+    cursor: pointer;
+}
+.error-data-show-button:after {
+    content: "\2026";
+    font-weight: bold;
+}
+
+.error-data-container {
+    margin-top: 0.25em;
+    font-family: 'Courier New', Courier, monospace;
+    white-space: pre;
+    overflow-x: auto;
+}
+
 [data-show-for-browser],
 [data-show-for-operating-system] {
     display: none;
diff --git a/ext/bg/js/request.js b/ext/bg/js/request.js
index 778f933b..02eed6fb 100644
--- a/ext/bg/js/request.js
+++ b/ext/bg/js/request.js
@@ -36,8 +36,9 @@ async function requestJson(url, action, params) {
     const responseText = await requestText(url, action, params);
     try {
         return JSON.parse(responseText);
-    }
-    catch (e) {
-        throw new Error('Invalid response');
+    } catch (e) {
+        const error = new Error(`Invalid response (${e.message || e})`);
+        error.data = {url, action, params, responseText};
+        throw error;
     }
 }
diff --git a/ext/bg/js/settings/anki.js b/ext/bg/js/settings/anki.js
index 5f7989b8..9adb2f2a 100644
--- a/ext/bg/js/settings/anki.js
+++ b/ext/bg/js/settings/anki.js
@@ -37,13 +37,35 @@ function _ankiSetError(error) {
     if (error) {
         node.hidden = false;
         node.textContent = `${error}`;
-    }
-    else {
+        _ankiSetErrorData(node, error);
+    } else {
         node.hidden = true;
         node.textContent = '';
     }
 }
 
+function _ankiSetErrorData(node, error) {
+    const data = error.data;
+    let message = '';
+    if (typeof data !== 'undefined') {
+        message += `${JSON.stringify(data, null, 4)}\n\n`;
+    }
+    message += `${error.stack}`.trimRight();
+
+    const button = document.createElement('a');
+    button.className = 'error-data-show-button';
+
+    const content = document.createElement('div');
+    content.className = 'error-data-container';
+    content.textContent = message;
+    content.hidden = true;
+
+    button.addEventListener('click', () => content.hidden = !content.hidden, false);
+
+    node.appendChild(button);
+    node.appendChild(content);
+}
+
 function _ankiSetDropdownOptions(dropdown, optionValues) {
     const fragment = document.createDocumentFragment();
     for (const optionValue of optionValues) {
diff --git a/ext/mixed/js/core.js b/ext/mixed/js/core.js
index 54e8a9d2..7fc01c94 100644
--- a/ext/mixed/js/core.js
+++ b/ext/mixed/js/core.js
@@ -56,7 +56,8 @@ function errorToJson(error) {
     return {
         name: error.name,
         message: error.message,
-        stack: error.stack
+        stack: error.stack,
+        data: error.data
     };
 }
 
@@ -64,6 +65,7 @@ function jsonToError(jsonError) {
     const error = new Error(jsonError.message);
     error.name = jsonError.name;
     error.stack = jsonError.stack;
+    error.data = jsonError.data;
     return error;
 }
 
@@ -74,7 +76,11 @@ function logError(error, alert) {
 
     const errorString = `${error.toString ? error.toString() : error}`;
     const stack = `${error.stack}`.trimRight();
-    errorMessage += (!stack.startsWith(errorString) ? `${errorString}\n${stack}` : `${stack}`);
+    if (!stack.startsWith(errorString)) { errorMessage += `${errorString}\n`; }
+    errorMessage += stack;
+
+    const data = error.data;
+    if (typeof data !== 'undefined') { errorMessage += `\nData: ${JSON.stringify(data, null, 4)}`; }
 
     errorMessage += '\n\nIssues can be reported at https://github.com/FooSoft/yomichan/issues';