diff --git a/lib/params/base_validator.rb b/lib/params/base_validator.rb
index 964ad553..c394519a 100644
--- a/lib/params/base_validator.rb
+++ b/lib/params/base_validator.rb
@@ -2,6 +2,8 @@
 
 module Params
   class BaseValidator
+    EMAIL_REGEXP = /\A[a-z0-9][\.']?(?:(?:[a-z0-9_-]+[\.\+'])*[a-z0-9_-]+)*@(?:[a-z0-9]+[\.-])*[a-z0-9]+\.[a-z]{2,}\z/i
+
     InvalidParameterError = Class.new(StandardError)
 
     def self.call(...)
@@ -65,6 +67,14 @@ module Params
       raise_error(message || "#{key} must follow the #{regexp.source} format")
     end
 
+    def email_format(params, key, message: nil)
+      return if params.blank?
+      return if params[key].blank?
+      return if params[key].to_s.strip.split(/\s*[;,]\s*/).all? { |email| email.match?(EMAIL_REGEXP) }
+
+      raise_error(message || "#{key} must follow the email format")
+    end
+
     def unique_value(params, key, message: nil)
       return unless params.is_a?(Array)
       return if params.none?
diff --git a/lib/params/submission_create_validator.rb b/lib/params/submission_create_validator.rb
index 0658aac2..eef14391 100644
--- a/lib/params/submission_create_validator.rb
+++ b/lib/params/submission_create_validator.rb
@@ -22,6 +22,7 @@ module Params
       required(params, %i[emails email])
 
       type(params, :emails, String)
+      email_format(params, :emails, message: 'emails are invalid')
       boolean(params, :send_email)
       type(params, :message, Hash)
 
@@ -43,8 +44,8 @@ module Params
       type(params, :completed_redirect_url, String)
       type(params, :bcc_completed, String)
       type(params, :reply_to, String)
-      format(params, :bcc_completed, /@/, message: 'bcc_completed email is invalid')
-      format(params, :reply_to, /@/, message: 'reply_to email is invalid')
+      email_format(params, :bcc_completed, message: 'bcc_completed email is invalid')
+      email_format(params, :reply_to, message: 'reply_to email is invalid')
       type(params, :message, Hash)
       type(params, :submitters, Array)
 
@@ -75,8 +76,8 @@ module Params
       type(submitter_params, :name, String)
       type(submitter_params, :reply_to, String)
       type(submitter_params, :email, String)
-      format(submitter_params, :email, /@/, message: 'email is invalid')
-      format(submitter_params, :reply_to, /@/, message: 'reply_to email is invalid')
+      email_format(submitter_params, :email, message: 'email is invalid')
+      email_format(submitter_params, :reply_to, message: 'reply_to email is invalid')
       type(submitter_params, :phone, String)
       format(submitter_params, :phone, /\A\+\d+\z/,
              message: 'phone should start with +<country code> and contain only digits')
@@ -106,7 +107,7 @@ module Params
       type(params, :order, String)
       type(params, :completed_redirect_url, String)
       type(params, :bcc_completed, String)
-      format(params, :bcc_completed, /@/, message: 'bcc_completed email is invalid')
+      email_format(params, :bcc_completed, message: 'bcc_completed email is invalid')
       type(params, :message, Hash)
 
       in_path(params, :message) do |message_params|
diff --git a/spec/lib/params/base_validator_spec.rb b/spec/lib/params/base_validator_spec.rb
new file mode 100644
index 00000000..193b9b33
--- /dev/null
+++ b/spec/lib/params/base_validator_spec.rb
@@ -0,0 +1,139 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Params::BaseValidator do
+  let(:validator) { described_class.new({}) }
+
+  describe '#email_format' do
+    it 'when email is valid' do
+      emails = [
+        '  john.doe@example.com  ',
+        'john.doe@example.com',
+        'jane+newsletter@domain.org',
+        'mike_smith@company.net',
+        'lisa-wong@sub.example.co.uk',
+        'peter@webmail.com',
+        'anna.jones123@my-domain.com',
+        'contact@company.email',
+        'info@my-company123.org',
+        'hello.world@business.info',
+        'feedback@new-domain.com',
+        'alerts+user@localdomain.net',
+        'webmaster@industry.biz',
+        'services@agency.example',
+        'george123@consultant.pro',
+        'sales-team@company.io'
+      ]
+
+      emails.each do |email|
+        expect { validator.email_format({ email: }, :email) }.not_to raise_error
+      end
+    end
+
+    it 'when signle email is invalid' do
+      emails = [
+        'jone.doe@',
+        'mike.smith@',
+        'jane.doe@@example.com',
+        '@example.com',
+        'lisa.wong@example',
+        'peter.parker..@example.com',
+        'anna.jones@.com',
+        'jack.brown@com',
+        'john doe@example.com',
+        'laura.martin@ example.com',
+        'dave.clark@example .com',
+        'susan.green@example,com',
+        'chris.lee@example;com',
+        'jenny.king@.example.com',
+        '.henry.ford@example.com',
+        'amy.baker@sub_domain.com',
+        'george.morris@-example.com',
+        'nancy.davis@example..com',
+        'kevin.white@.',
+        'diana.robinson@.example..com',
+        'oliver.scott@example.c',
+        'email1@g.comemail@g.com',
+        'user.name@subdomain.example@example.com',
+        'double@at@sign.com',
+        'user@@example.com',
+        'email@123.123.123.123',
+        'this...is@strange.but.valid.com',
+        'mix-and.match@strangely-formed-email_address.com',
+        'email@domain..com',
+        'user@-weird-domain-.com',
+        'user.name@[IPv6:2001:db8::1]',
+        'tricky.email@sub.example-.com',
+        'user@domain.c0m'
+      ]
+
+      emails.each do |email|
+        expect do
+          validator.email_format({ email: }, :email)
+        end.to raise_error(described_class::InvalidParameterError, 'email must follow the email format')
+      end
+    end
+
+    it 'when multiple emails are valid' do
+      emails = [
+
+        'john.doe@example.com, jane.doe+newsletter@domain.org',
+        'joshua@automobile.car ; chloe+fashion@food.delivery',
+        'mike-smith@company.net;lisa.wong-sales@sub.example.co.uk',
+        'peter.parker+info@webmail.com,laura.martin-office@company.co',
+        'anna.jones123@my-domain.com, jack.brown+work@college.edu',
+        'susan.green@business-info.org; dave.clark+personal@nonprofit.org',
+        'chris.lee+team@new-domain.com;jenny.king.marketing@localdomain.net',
+        'george.morris@consultant.pro; nancy.davis-office@company.io',
+        'joshua-jones@automobile.car; chloe.taylor+fashion@food.delivery',
+        'ryan.moore+alerts@music-band.com,isabella.walker.design@fashion.design',
+        'support-team@company.com, contact.us@domain.org',
+        'admin.office@industry.biz, hr.department@service.pro',
+        'feedback@agency-example.org; hello.world@creative-studio.net',
+        'sales-team@e-commerce.shop, support.department@technology.co',
+        'media.contact@financial.servicesl; events-coordinator@food.delivery',
+        'order@music-band.com; info.support@creative.example',
+        'design.team@webmail.com , admin-office@company.co',
+        'contact.sales@sub-example.co.uk, support+info@legal.gov',
+        'support@media.group;subscribe-updates@concert.events'
+      ]
+
+      emails.each do |email|
+        expect { validator.email_format({ email: }, :email) }.not_to raise_error
+      end
+    end
+
+    it 'when multiple emails are invalid' do
+      emails = [
+        'jone@gmail.com, ,mike@gmail.com',
+        'john.doe@example.com  dave@nonprofit.org',
+        '; oliver.scott@example.com',
+        'amy.baker@ example.com, george.morris@ example.com',
+        'jenny.king@example.com . diana.robinson@example.com',
+        'nancy.davis@.com, henry.ford@.com',
+        'jack.brown@example.com, laura.martin@example .com',
+        'anna.jones@example,com lisa.wong@example.com',
+        'dave.clark@example.com kevin.white@example;com',
+        'susan.green@ example.com; john.doe@example.com',
+        'amy.baker@sub_domain.com george.morris@-example.com',
+        'nancy.davis@example..com john.doe@example.c',
+        'peter.parker@example.com, .henry.ford@example.com',
+        'diana.robinson@.example..com, mike.smith@.',
+        'oliver.scott@example.com; laura.martin@ example.com, jane.doe@@example.com'
+      ]
+
+      emails.each do |email|
+        expect do
+          validator.email_format({ email: }, :email)
+        end.to raise_error(described_class::InvalidParameterError, 'email must follow the email format')
+      end
+    end
+
+    it 'when email is invalid with custom message' do
+      expect do
+        validator.email_format({ email: 'jone.doe@' }, :email, message: 'email is invalid')
+      end.to raise_error(described_class::InvalidParameterError, 'email is invalid')
+    end
+  end
+end
diff --git a/spec/requests/submissions_spec.rb b/spec/requests/submissions_spec.rb
index 5062662c..3a9590d8 100644
--- a/spec/requests/submissions_spec.rb
+++ b/spec/requests/submissions_spec.rb
@@ -83,6 +83,20 @@ describe 'Submission API', type: :request do
       expect(response.parsed_body[2]['email']).to eq('mike.doe@example.com')
     end
 
+    it 'returns an error if the submitter email is invalid' do
+      post '/api/submissions', headers: { 'x-auth-token': author.access_token.token }, params: {
+        template_id: templates[0].id,
+        send_email: true,
+        submitters: [
+          { role: 'First Role', email: 'john@example' }
+        ]
+      }.to_json
+
+      expect(response).to have_http_status(:unprocessable_entity)
+
+      expect(response.parsed_body).to eq({ 'error' => 'email is invalid in `submitters[0]`.' })
+    end
+
     it 'returns an error if the template fields are missing' do
       templates[0].update(fields: [])
 
@@ -113,16 +127,28 @@ describe 'Submission API', type: :request do
 
   describe 'POST /api/submissions/emails' do
     it 'creates a submission using email' do
-      post '/api/submissions', headers: { 'x-auth-token': author.access_token.token }, params: {
+      post '/api/submissions/emails', headers: { 'x-auth-token': author.access_token.token }, params: {
         template_id: templates[0].id,
-        emails: 'john.doe@example.com'
+        emails: 'john.doe@example.com,jane.doe@example.com'
       }.to_json
 
       expect(response).to have_http_status(:ok)
 
-      submission = Submission.last
+      submissions = Submission.last(2)
+      submissions_body = submissions.reduce([]) { |acc, submission| acc + create_submission_body(submission) }
 
-      expect(response.parsed_body).to eq(JSON.parse(create_submission_body(submission).to_json))
+      expect(response.parsed_body).to eq(JSON.parse(submissions_body.to_json))
+    end
+
+    it 'returns an error if emails are invalid' do
+      post '/api/submissions/emails', headers: { 'x-auth-token': author.access_token.token }, params: {
+        template_id: templates[0].id,
+        emails: 'amy.baker@example.com, george.morris@example.com@gmail.com'
+      }.to_json
+
+      expect(response).to have_http_status(:unprocessable_entity)
+
+      expect(response.parsed_body).to eq({ 'error' => 'emails are invalid' })
     end
   end