An app that can only be used while someone is actively looking at it is a limited app. Email is what turns a passive tool into something that stays in touch with your users — confirming their order, reminding them of an upcoming event, verifying their identity, or keeping them up to date with a newsletter. It is the difference between an app that serves people and one that builds a relationship with them.
Caffeine apps can send emails natively — no external email provider and no API keys required. You describe what you want in the chat, and the AI generates the backend code that handles sending. All email delivery runs through Caffeine's managed infrastructure using Amazon SES.
Email sending is available on Plus and Pro plans.
What kinds of emails can your app send?
Caffeine supports five distinct email capabilities, each suited to a different use case:
Transactional emails
The most common type. Use these for event-driven, one-to-one messages: order confirmations, booking receipts, account notifications, password resets, reminders, and anything else triggered by something a user did. Each recipient gets their own individual message.
Email verification
Lets your app confirm that a user actually owns the email address they provided. The system sends a message containing a unique link; when the user clicks it, their address is marked as verified. Your app can then restrict certain actions to users with verified email addresses.
Marketing and newsletter emails
Send personalized bulk messages to subscribers who have opted in and verified their email address. Messages are organized by topic (for example, "Weekly Newsletter" or "Product Updates"), and every marketing email includes a working unsubscribe link. Users who unsubscribe from a topic are automatically removed from that audience.
Calendar event invitations
Send meeting or event invitations that attach to standard calendar applications — Google Calendar, Apple Calendar, Outlook, and others. Your app can send initial invitations, send updates when details change, and send cancellations. The invitation format follows the iCalendar standard, so recipients can add events to their calendars with one click.
Raw multi-recipient email
Sends a single message to a list of recipients using standard to, cc, and bcc addressing — all recipients can see who else received the message. This is suited for internal group communications (for example, notifying a team of attendees). It is not appropriate for sending individual service emails to multiple users, because it exposes all recipients' addresses to each other. Limited to 50 recipients per send.
How email delivery works
Caffeine handles delivery behind the scenes. When your app sends an email, the request is routed through Caffeine's infrastructure, which delivers the message via Amazon SES. You do not need to create an account with any email provider or manage delivery settings.
Outbound emails are sent from your app's domain — whatever address your project uses is the address that appears in the "from" field. How this works depends on which type of domain your project uses:
Default Caffeine domain
If your project uses the default your-project.caffeine.xyz address, emails are sent from that domain automatically. No setup is needed.
Custom domain purchased through Caffeine
If you purchased a domain through Caffeine (for example, mydomain.com), emails are sent from that domain automatically. Caffeine creates the required email DNS records (DKIM, SPF, and DMARC) on your behalf when the domain is set up.
External domain (bring your own)
If you connected a domain you already own (for example, www.mydomain.com), you must add additional DNS records at your registrar for email to work. Caffeine displays these records alongside the web routing records when you set up the domain — they are labeled as mail records in the setup instructions.
If your app sends email and these mail DNS records are not configured, emails will not be delivered. There is no error message — emails simply fail to arrive. Make sure all DNS records shown by Caffeine are added at your registrar, including the mail records.
Plan requirement
Email sending requires a Plus or Pro subscription. If you are on a Basic or Starter plan, the AI will not generate email-sending code when you ask for it. Upgrading your plan unlocks the feature immediately.
Beta status
Email sending is currently in beta. The core functionality works in production, but you may encounter rough edges. If something doesn't behave as expected, contact support.
Frequently asked questions
Do I need to set up an email provider or configure DNS to use email sending?
You do not need an account with any email provider, and you do not need API keys. If your project uses the default Caffeine domain or a domain purchased through Caffeine, no DNS setup is needed either — everything is handled automatically. If you connected your own external domain, you must add the mail DNS records that Caffeine provides during domain setup. Without those records, email will not be delivered.
Does my app send email from my custom domain?
Yes. Outbound emails are sent from whatever domain your project uses. If your project uses mydomain.com, emails come from that domain. If it uses the default Caffeine domain, emails come from that domain.
Can I choose the sender email address?
Partially. The sender address has the format prefix@your-app-domain. The domain part is always your project's domain and cannot be changed independently. The prefix (the part before the @) is chosen by the AI when it generates the email code — by default it uses no-reply. You can ask the AI to change the prefix in the chat, for example: "Change the sender address for order emails to 'orders'." See Setup the Email Integration for more details.
Is there a limit to how many emails my app can send?
There is no documented per-day or per-month sending limit for the standard email types. The raw multi-recipient email component is limited to 50 recipients per send (to + cc + bcc combined). If your app needs very high sending volumes, contact support to discuss your use case.
Can I use email sending on a Starter plan?
No. Email sending requires a Plus or Pro subscription. If you are on Basic or Starter, the AI will not generate email-sending code.
What happens to marketing emails sent to users who later unsubscribe?
Unsubscribed users are automatically excluded from future sends on that topic. The unsubscribe action is final — they will not receive further marketing emails for that topic unless they actively resubscribe.
Can my app receive incoming emails?
No. Caffeine's email integration is outbound only. There is no inbox, and replies to emails sent by your app are not delivered anywhere. Every sender address your app uses is effectively a no-reply address, regardless of the prefix you choose. If you need users to contact you, include a link to a contact form or support page in the email body rather than expecting them to reply.