Sending emails from your app

Choose how to send emails from your Base44 app: built-in emails, workflows that send automatically, a custom email domain, Resend, or another email provider.

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.

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.

Who you can email

Who your app can email depends on whether the person has signed up to your app:

• People who’ve signed up: Your app can email them on any plan, including the Free plan.
• People who haven’t signed up: Your app needs a paid plan and a custom domain connected and verified. This is the domain your app is served on, not a custom email sending domain. Each of these emails goes to one recipient at a time.

If you use a workflow to send emails instead, its Send email step can only email people who’ve signed up to your app, whatever your plan. To email anyone else from a workflow, use a backend function step.

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.

Setting up email with the AI chat

Notes:

• Built-in emails 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 [e-mail]. 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.

Daily sending limits

How many built-in emails your app can send each day depends on whether the people you’re emailing have signed up to your app.

How many emails your app can send:

• People who’ve signed up: There’s no daily cap. Each email uses integration credits, so your plan’s credits set how many you can send.
• People who haven’t signed up: Your app can email up to 20 new people a day, and each person can get up to 3 emails a day from your app.

These limits reset the next day. Emails to people who haven’t signed up also have an hourly limit, and if your app keeps trying to send over it, those emails are paused for a few hours. Emails to people who’ve signed up keep working. To send newsletters or other high-volume emails, use the Resend integration.

Changing the sender name

Built-in emails come from [e-mail] and show your app’s name as the sender. To show a different name in people’s inboxes, ask the AI chat. This changes only the name, not the email address. For example:

Send all emails from my app with the sender name "Hattery Support".

If you’ve connected a custom email domain, your emails use the sender name and address you set for that domain instead, and the AI chat can’t change them. You can edit them on your Domains page, as covered in editing sender details.

Built-in emails don’t support a separate reply-to address, so replies go to the address the email came from. To get replies, connect a custom email domain with an address you check, such as [e-mail], or use the Resend integration.

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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

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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 that send emails from your Base44 app

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Emailing form submissions

When someone fills in a form in your app, such as a contact form, each submission is saved as a record in your app’s data. You can see every submission on the Data page, and you can also have the details emailed to you or send a confirmation to the person who filled in the form. Each email uses integration credits, like any other built-in email.

Who can receive these emails:

• People who have signed up to your app: Your app can email them whatever plan you’re on.
• Anyone else: To email someone who hasn’t signed up to your app, such as a separate business inbox or the person who filled in the form, you need a paid plan and a verified custom domain on your app. Learn more about who you can email.

There are 2 ways to set this up. Ask the AI chat for a simple email each time someone submits the form, or use a workflow when you want more steps:

Ask the AI chat to email you

Describe the form, who should get the email, and what it should include. For example:

When someone submits my contact form, email the submission to [e-mail] with their name, email address, and message.

The AI sets this up using the built-in email integration. Send a test submission from your app to check that the email arrives.

Send the email from a workflow

Use a workflow when you want more than one step, such as emailing yourself and then following up with the person a few days later. Ask the AI chat, for example:

Create a workflow that runs when a new contact form submission is created and emails me the details.

The workflow starts each time a new submission is saved. Learn more about workflows that react to your data.

You need the Builder plan or above to use workflows. A workflow’s Send email step only emails people who have signed up to your app. To email anyone else, ask the AI chat to send the email from a backend function step instead.

If a submission email doesn’t arrive, check your spam folder and mark it as not spam. To send from your own branded address instead of the default sender, connect a custom email domain.

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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, [e-mail]) instead of [e-mail] 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.

How do I decide between built-in emails and the Resend integration?

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.

Can I combine different email options in the same app?

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.

Can I use Zapier to send emails from my app?

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.

Do I need a custom domain to send emails?

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.

Can my app email people who have not signed up to it?

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. This works for built-in emails, not for a workflow’s Send email step.

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.