diff --git a/src/components/join-flow/email-step.jsx b/src/components/join-flow/email-step.jsx
index 88a24c97a..5e42edeac 100644
--- a/src/components/join-flow/email-step.jsx
+++ b/src/components/join-flow/email-step.jsx
@@ -4,9 +4,9 @@ const React = require('react');
 const PropTypes = require('prop-types');
 import {Formik} from 'formik';
 const {injectIntl, intlShape} = require('react-intl');
-const emailValidator = require('email-validator');
 const FormattedMessage = require('react-intl').FormattedMessage;
 
+const validate = require('../../lib/validate');
 const JoinFlowStep = require('./join-flow-step.jsx');
 const FormikInput = require('../../components/formik-forms/formik-input.jsx');
 const FormikCheckbox = require('../../components/formik-forms/formik-checkbox.jsx');
@@ -75,11 +75,16 @@ class EmailStep extends React.Component {
     }
     validateEmail (email) {
         if (!email) return this.props.intl.formatMessage({id: 'general.required'});
-        const isValidLocally = emailValidator.validate(email);
-        if (isValidLocally) {
-            return null; // TODO: validate email address remotely
-        }
-        return this.props.intl.formatMessage({id: 'registration.validationEmailInvalid'});
+        const localResult = validate.validateEmailLocally(email);
+        if (!localResult.valid) return this.props.intl.formatMessage({id: localResult.errMsgId});
+        return validate.validateEmailRemotely(email).then(
+            remoteResult => {
+                if (remoteResult.valid === true) {
+                    return null;
+                }
+                return this.props.intl.formatMessage({id: remoteResult.errMsgId});
+            }
+        );
     }
     validateForm () {
         return {};
@@ -119,6 +124,8 @@ class EmailStep extends React.Component {
                         handleSubmit,
                         isSubmitting,
                         setFieldError,
+                        setFieldTouched,
+                        setFieldValue,
                         validateField
                     } = props;
                     return (
@@ -161,7 +168,11 @@ class EmailStep extends React.Component {
                                 validationClassName="validation-full-width-input"
                                 /* eslint-disable react/jsx-no-bind */
                                 onBlur={() => validateField('email')}
-                                onFocus={() => setFieldError('email', null)}
+                                onChange={e => {
+                                    setFieldValue('email', e.target.value);
+                                    setFieldTouched('email');
+                                    setFieldError('email', null);
+                                }}
                                 /* eslint-enable react/jsx-no-bind */
                                 onSetRef={this.handleSetEmailRef}
                             />
diff --git a/src/lib/validate.js b/src/lib/validate.js
index b4fd84f31..5df20b0e4 100644
--- a/src/lib/validate.js
+++ b/src/lib/validate.js
@@ -1,5 +1,6 @@
 module.exports = {};
 const api = require('./api');
+const emailValidator = require('email-validator');
 
 module.exports.validateUsernameLocally = username => {
     if (!username || username === '') {
@@ -67,3 +68,36 @@ module.exports.validatePasswordConfirm = (password, passwordConfirm) => {
     }
     return {valid: true};
 };
+
+module.exports.validateEmailLocally = email => {
+    if (!email || email === '') {
+        return {valid: false, errMsgId: 'general.required'};
+    } else if (emailValidator.validate(email)) {
+        return {valid: true};
+    }
+    return ({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+};
+
+module.exports.validateEmailRemotely = email => (
+    new Promise(resolve => {
+        api({
+            host: '', // not handled by API; use existing infrastructure
+            params: {email: email},
+            uri: '/accounts/check_email/'
+        }, (err, body, res) => {
+            if (err || res.statusCode !== 200 || !body || body.length < 1 || !body[0].msg) {
+                resolve({valid: false, errMsgId: 'general.apiError'});
+            }
+            switch (body[0].msg) {
+            case 'valid email':
+                resolve({valid: true});
+                break;
+            case 'Scratch is not allowed to send email to this address.': // e.g., bad TLD or block-listed
+            case 'Enter a valid email address.':
+            default:
+                resolve({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+                break;
+            }
+        });
+    })
+);
diff --git a/test/unit/lib/validate.test.js b/test/unit/lib/validate.test.js
index 03922882f..a051e1faa 100644
--- a/test/unit/lib/validate.test.js
+++ b/test/unit/lib/validate.test.js
@@ -63,4 +63,52 @@ describe('unit test lib/validate.js', () => {
         response = validate.validatePasswordConfirm('', 'abcdefg');
         expect(response).toEqual({valid: false, errMsgId: 'registration.validationPasswordConfirmNotEquals'});
     });
+
+    test('validate email address locally', () => {
+        let response;
+        expect(typeof validate.validateEmailLocally).toBe('function');
+
+        // permitted addresses:
+        response = validate.validateEmailLocally('abc@def.com');
+        expect(response).toEqual({valid: true});
+        response = validate.validateEmailLocally('abcdefghijklmnopqrst@abcdefghijklmnopqrst.info');
+        expect(response).toEqual({valid: true});
+        response = validate.validateEmailLocally('abc-def-ghi@jkl-mno.org');
+        expect(response).toEqual({valid: true});
+        response = validate.validateEmailLocally('_______@example.com');
+        expect(response).toEqual({valid: true});
+        response = validate.validateEmailLocally('email@example.museum');
+        expect(response).toEqual({valid: true});
+        response = validate.validateEmailLocally('email@example.co.jp');
+        expect(response).toEqual({valid: true});
+
+        // non-permitted addresses:
+        response = validate.validateEmailLocally('');
+        expect(response).toEqual({valid: false, errMsgId: 'general.required'});
+        response = validate.validateEmailLocally('a');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('abc@def');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('abc@def.c');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('abc😄def@emoji.pizza');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('あいうえお@example.com');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('Abc..123@example.com');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('Joe Smith <email@example.com>');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('email@example@example.com');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('email@example..com');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+
+        // edge cases:
+        // these are strictly legal according to email addres spec, but rejected by library we use:
+        response = validate.validateEmailLocally('email@123.123.123.123');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+        response = validate.validateEmailLocally('much."more unusual"@example.com');
+        expect(response).toEqual({valid: false, errMsgId: 'registration.validationEmailInvalid'});
+    });
 });