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When you create an app with AI in Base44, you can choose how to send emails, from quick transactional messages to scheduled campaigns. You can use Base44 built-in emails or send from a custom email domain for branded messages. For more control, you can connect an external email provider such as Resend, use another external integration, or connect your own email service. You can also combine any of these options with workflows to send emails on a schedule or when something changes in your data, and design how your emails look.
Welcome email from Hattery with a greeting, account confirmation, and three getting-started tips

A welcome email sent from a Base44 app

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Base44 built-in emails

Base44’s built-in SendEmail integration comes preinstalled in every app and needs no extra setup or API keys. It lets you send transactional emails from your app, customize the sender name that appears in the recipient’s inbox, and include plain text or rich HTML content in the email body. You can ask the AI chat to set this up for you, for example by saying When someone signs up, send them a welcome email. Base44 calls the built-in email integration, which you can edit and test using the AI chat or from Code in your dashboard. To make these emails look like your app, design them from Emails in your dashboard. Learn more about designing your app’s emails.

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Who you can email

On any plan, including the Free plan, your app can email anyone who has signed up to it. To email an address that has not signed up, your app needs to be on a paid plan and have a custom domain connected and verified. Each of these emails goes to one recipient at a time. This is your app’s own custom domain, the one your app is served on, not a custom email sending domain. If an email is not sent, it appears in your app logs with the reason, so you can see whether the plan, the custom domain, or a sending limit stopped it.
Asking the AI chat to set up emails from your app

Setting up email with the AI chat

Notes:
  • Built-in emails do not support external mailing lists. They can include up to 5 file attachments, such as PDFs, images, CSV, Word, or Excel files, up to 5 MB each and 10 MB in total.
  • If you want built-in emails to come from a branded address instead of a generic sender, you can connect a custom email domain so messages send from an address like support@your-domain.com. See more below.
  • Standard emails that use the default sending domain typically consume ~1 integration credit per email, while emails sent from a custom email domain consume ~2 integration credits.

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Resend external integration

Resend is an external email delivery service that you connect to Base44. When you use Resend, emails are sent through your own Resend account rather than Base44’s built-in email delivery.
Note: Resend is an external service, and Base44 does not provide support for issues related to Resend.
The Resend integration connects your app to Resend for more advanced or higher-volume email flows. You can use richer templates and layouts, improve deliverability with domain authentication, and track performance in the Resend dashboard. Resend works well for transactional emails such as password reset links or order confirmations, as well as newsletters, lifecycle campaigns, and other outbound email from your own domain. You connect Resend through the integrations catalog and add your API key, then describe the email flows you want in the AI chat. You can ask the AI to use Resend for specific events (for example, when someone subscribes or completes a purchase), and generate the backend functions that call the Resend integration. Learn more about setting up the Resend integration
Note: The Resend integration is available on the Builder plan and above.
Setting up Resend on your Base44 app to send emails

Setting up Resend

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Automated emails

Use workflows to send emails automatically, on a schedule or when something happens in your app. For example, send a welcome email when someone signs up, a follow-up 2 days later, or a summary every Monday morning. To set one up, ask the AI chat, for example When someone signs up, send them a welcome email, then a tips email 2 days later. The AI designs each email in your app’s style and adds it to a workflow as a Send email step. You can see and manage your workflows from Workflows in your app’s dashboard, and the emails themselves from Emails. Learn more about creating workflows and designing your app’s emails.
Workflows are available on the Builder plan and above. If your app still uses automations, you can switch them to workflows.
Workflows page in the app dashboard listing active workflows

Workflows that send emails from your Base44 app

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Emails from custom domains

With the Base44 built-in email service, you can send emails from your own domain (for example, support@your-domain.com) instead of no-reply@base44-apps.com for all built-in email types. To use this, you need your app to be connected to a custom domain. Each app can connect one custom email domain, and you cannot set multiple sender addresses on the same domain.
Notes:
  • Custom domain emails are available on the Starter plan and above.
  • Emails sent from a custom email domain consume 2 integration credits.
Learn how to send emails from a custom domain

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Additional email providers

You are not limited to Resend. If you already use another email provider that exposes an HTTP API, you can connect it to your Base44 app. One option is to call the provider directly from backend functions, using secrets to store API keys and other credentials. This gives you full control over the payload without creating a reusable catalog integration. Another option is to wrap the provider in a custom integration so it appears in your private catalog. You can then reuse that integration across multiple apps or share it with your workspace without repeating the setup each time. This approach is helpful when your team already relies on a specific provider, when you need features that only that provider offers, or when you want consistent email behavior across many apps built on Base44. Learn more about external API calls with backend functions and creating your own custom integrations
Note: External and custom integrations are available on the Builder plan and above.

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FAQs

Click a question below to learn more about sending emails from your app.
Use built-in emails when you want branded emails you can design in your dashboard with no extra setup.Use the Resend integration when you need deliverability tools, tracking, audiences, or higher-volume sending through your own Resend account.
Yes. You do not need one email approach for your whole app. Use built-in emails for low-volume flows, Resend for higher-volume or marketing emails, workflows for scheduled and recurring messages, and a custom email domain for branded sending.Some teams also connect a specialist or in-house provider through backend functions or custom integrations. You can move individual flows to more advanced options as your needs grow.
Yes, in an indirect way. The Zapier integration lets your app send data to Zapier, and then Zapier can trigger emails through tools such as Gmail, Outlook, or its own email actions. This is useful when you already automate workflows in Zapier and want your Base44 app to be another trigger. For details, see the Zapier integration guide.
You do not need one to email people who have signed up to your app. Adding a custom email sending domain becomes more important when you care about consistent branding, higher deliverability, or larger sending volumes.Emailing addresses that have not signed up is different. That needs a paid plan and a verified custom domain on the app itself.You also need a custom email domain to send your own version of the email verification email. Learn more about customizing built-in emails.
Yes, when your app is on a paid plan and has a custom domain connected and verified. Each message goes to one recipient at a time.Without both of those, built-in emails reach only the people who have signed up to your app. Sending to addresses that have not signed up is meant for transactional messages, and your app’s sending can be paused if recipients report the messages as spam or too many of them fail to deliver.