BYO ESP
Bring Your Own ESP
Connect SendGrid, Google Workspace, SMTP, or IMAP and EmailUX renders or triggers from your account. Your ESP handles delivery, warming, and bounces — EmailUX handles the design and developer experience.
01
Connect any ESP
Plug in SendGrid, Google Workspace, or any SMTP/IMAP account. Mail goes out from your sending account, on your reputation, with no proxying through EmailUX infrastructure.
02
Render via /v1/render
Call the render endpoint to receive ready-to-send HTML and a subject line for any stored Studio experience. Hand the result to your ESP yourself or to any internal pipeline.
03
Send via /v1/deliver
Call the deliver endpoint and EmailUX renders the template and dispatches the message through your connected ESP in a single call.
Why bring your own ESP?
Most product teams already have an ESP relationship — a SendGrid account, a Google Workspace tenant, or a self-hosted SMTP server. Switching costs are real: warmed IPs, sender reputation, contracts, and support relationships.
EmailUX does not try to replace any of that. We sit between your application and your ESP, providing a Studio for designing templates and an API for rendering or triggering sends through the account you already trust.
Supported integrations
- SendGrid. Connect a SendGrid API key and the
/v1/deliverendpoint will dispatch through your SendGrid account using your domain and your IPs. - Google Workspace. Authenticate a Workspace mailbox and EmailUX will trigger sends from that mailbox.
- SMTP / IMAP. Use any standards-compliant server — self-hosted Postfix, Amazon SES SMTP, Mailgun SMTP, or anything in between.
What your ESP handles, not EmailUX
Because the actual send happens from your ESP account, the deliverability stack lives there too. Your ESP is responsible for:
- Sender reputation and IP/domain warming.
- Bounce, complaint, and unsubscribe processing.
- SPF, DKIM, and DMARC alignment for your sending domain.
- Compliance with the Gmail and Yahoo bulk-sender rules.
EmailUX publishes educational guides on these topics so your team can configure things correctly on whichever ESP you pick — see the email authentication guide, the subdomain strategy guide, and the Gmail and Yahoo 2025 bulk-sender requirements.
Why EmailUX with your ESP
Most ESPs have weak template tooling. EmailUX brings an accessible, localization-aware, AI-assisted Studio — plus a typed transactional email API and a marketing campaigns workspace — on top of the ESP you already use.
Design once, send through your existing ESP
Reserve early access to EmailUX and start designing on-brand, localized templates, then render or trigger sends through your connected SendGrid, Google Workspace, SMTP, or IMAP account.