diff --git a/src/WebformBuilder.js b/src/WebformBuilder.js
index de38ce9d6b..407d699be4 100644
--- a/src/WebformBuilder.js
+++ b/src/WebformBuilder.js
@@ -1289,6 +1289,9 @@ export default class WebformBuilder extends Component {
   highlightInvalidComponents() {
     const repeatablePaths = this.findRepeatablePaths();
     let hasInvalidComponents = false;
+    // Matches anything expect letters and  '_' at the beginning of the key and anything except of letters, numbers,
+    // '-', '.' and '_' in the rest of the key
+    const badCharacters = /^[^A-Za-z_]+|[^A-Za-z0-9\-._]+/g;
 
     this.webform.everyComponent((comp) => {
       const path = comp.path;
@@ -1296,6 +1299,11 @@ export default class WebformBuilder extends Component {
         comp.setCustomValidity(this.t('apiKey', { key: comp.key }));
         hasInvalidComponents = true;
       }
+
+      if (comp.key.replace(badCharacters, '') === '') {
+        comp.setCustomValidity(this.t('apiKeyNotValid', { key: comp.key }));
+        hasInvalidComponents = true;
+      }
     });
 
     this.emit('builderFormValidityChange', hasInvalidComponents);
diff --git a/src/translations/en.js b/src/translations/en.js
index aa3df6b2e1..163e241fb6 100644
--- a/src/translations/en.js
+++ b/src/translations/en.js
@@ -76,6 +76,7 @@ export default {
   reCaptchaTokenValidationError: 'ReCAPTCHA: Token validation error',
   reCaptchaTokenNotSpecifiedError: 'ReCAPTCHA: Token is not specified in submission',
   apiKey: 'API Key is not unique: {{key}}',
+  apiKeyNotValid: 'API Key is not valid: {{key}}',
   typeRemaining: '{{ remaining }} {{ type }} remaining.',
   typeCount: '{{ count }} {{ type }}',
   requiredDayField: '{{ field }} is required',
diff --git a/test/forms/formWithNumericKeys.js b/test/forms/formWithNumericKeys.js
new file mode 100644
index 0000000000..3e76bea557
--- /dev/null
+++ b/test/forms/formWithNumericKeys.js
@@ -0,0 +1,30 @@
+export default {
+  type: 'form',
+  display: 'form',
+  components: [
+    {
+      label: 'Text Field',
+      applyMaskOn: 'change',
+      tableView: true,
+      key: 'test',
+      type: 'textfield',
+      input: true,
+    },
+    {
+      label: 'Text Field',
+      applyMaskOn: 'change',
+      tableView: true,
+      key: '1234',
+      type: 'textfield',
+      input: true,
+    },
+    {
+      type: 'button',
+      label: 'Submit',
+      key: 'submit',
+      disableOnInvalid: true,
+      input: true,
+      tableView: false,
+    },
+  ],
+};
diff --git a/test/unit/WebformBuilder.unit.js b/test/unit/WebformBuilder.unit.js
index 2ef7149a91..21911c8346 100644
--- a/test/unit/WebformBuilder.unit.js
+++ b/test/unit/WebformBuilder.unit.js
@@ -10,6 +10,7 @@ import testApiKeysUniquifying from '../forms/testApiKeysUniquifying';
 import formBasedOnWizard from '../forms/formBasedOnWizard';
 import formWithFormController from '../forms/formWithFormController';
 import simpleWebform from '../forms/simpleWebform';
+import formWithNumericKeys from '../forms/formWithNumericKeys';
 
 global.requestAnimationFrame = (cb) => cb();
 global.cancelAnimationFrame = () => {};
@@ -378,7 +379,17 @@ describe('WebformBuilder tests', function() {
         }, 200);
       }, 200)
     }).catch(done);
-  })
+  });
+
+  it('Should show API error when components have invalid API keys', (done) => {
+    const builder = Harness.getBuilder();
+    builder.webform.setForm(formWithNumericKeys).then(() => {
+      builder.highlightInvalidComponents();
+      const component = builder.webform.components[1];
+      assert.equal(component.refs.messageContainer.textContent.trim(), 'apiKeyNotValid');
+      done();
+    }).catch(done);
+  });
 });
 
 describe('Select Component selectData property', () => {