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    GuideIntegrationsSupabase

    Supabase Integration

    Connect Supabase to Simply Send to route your project's auth emails — magic links, OTPs, password resets, and email confirmations — through your own branded domain with full deliverability control.

    Overview

    By default, Supabase sends auth emails from a shared Supabase domain. Connecting Simply Send gives you:

    Branded Sender Identity

    Magic links and OTPs arrive from [email protected], not Supabase's shared pool.

    Superior Deliverability

    Your dedicated sending reputation means auth emails land in inboxes, not spam folders.

    Real-time Analytics

    Track every magic link delivery, open, and bounce from your Simply Send dashboard.

    No Rate Cap Surprises

    Bypass Supabase's outbound email limits. Scale auth emails on your own terms.

    Connection Methods

    There are two ways to connect Supabase to Simply Send. Both result in Supabase auth emails flowing through your Simply Send SMTP infrastructure.

    Recommended

    Method 1: One-Click OAuth

    The OAuth flow handles everything automatically. Simply Send creates a dedicated SMTP credential and pushes the configuration directly to your Supabase project via the Supabase Management API — no manual copy-pasting required.

    1. 1Go to Integrations in your Simply Send dashboard and click Connect on the Supabase card.
    2. 2You'll be redirected to Supabase's OAuth authorization page. Grant Simply Send access to your organisation.
    3. 3Select the Supabase project you want to configure, choose your verified sending domain and a sender name.
    4. 4Click Configure. Simply Send automatically creates an SMTP credential and updates your Supabase project's Auth SMTP settings.
    • Automatic SMTP credential creation
    • Auto-configures Supabase Auth SMTP settings via Management API
    • Supports connecting multiple Supabase projects
    Free tier: 1 OAuth connection. Paid plans: 5 connections by default — submit a request to increase your limit.

    Method 2: Manual SMTP

    Prefer full control? Create an SMTP credential in Simply Send and manually enter the settings into your Supabase project's Auth configuration.

    No separate Supabase connection limit applies here. Your plan's standard SMTP credential quota applies instead.
    1. 1In Simply Send, go to SMTP Credentials and create a new credential tied to your verified domain.
    2. 2Copy the Host, Port, Username, and Password from the credential detail panel.
    3. 3In your Supabase project, go to Settings → Auth → SMTP Settings. Enable custom SMTP and paste the credentials.
    4. 4Set the Sender Email to [email protected] and click Save.
    Supabase → Settings → Auth → SMTP Settings
    Host:     <smtp-server-from-setup>
Port:     587  (STARTTLS)
Username: your-smtp-username
Password: ••••

Sender:   [email protected]

    Compliance Variables

    Simply Send requires two compliance variables in every email HTML body before it will deliver the message. You must add them to each of your Supabase Auth email templates in Supabase Dashboard → Auth → Email Templates.

    Edit each template (Confirm signup, Magic Link, Change Email Address, Reset Password, etc.) and paste the following variables into the HTML body. They will be substituted at send time with the unsubscribe link and company address configured under Templates → Compliance in Simply Send:

    <!-- Required in every email template -->
<div>{{unsubscribe_email_html}}</div>
<div>{{company_address_html}}</div>

<!-- Optional -->
<div>{{report_abuse_email_html}}</div>
    Emails missing {{unsubscribe_email_html}} or {{company_address_html}} will be rejected by Simply Send with a MISSING_TEMPLATE_VARIABLES error.

    Connection Limits

    Limits differ depending on the connection method you choose.

    Method 1 — OAuth Connections

    Free tier

    1 connection

    Paid plans

    5 (default)

    If you reach your limit, the Connect button changes to an upgrade or quota request link. Paid users can also submit a request to increase beyond the 5-connection default.

    Method 2 — Manual SMTP

    No separate Supabase connection limit applies. The only limit is your plan's standard SMTP credential quota. As long as you have available SMTP credential slots, you can create credentials and use them in as many Supabase projects as you like.

    Prerequisites

    • Verified Transactional domain — You must have at least one verified Transactional domain in Simply Send. Marketing domains are not supported for this integration.
    • Supabase project Owner or Admin role — The OAuth flow uses the Supabase Management API which requires Owner or Administrator permissions on the target project.
    • Supabase OAuth configured (Method 1 only) — The Simply Send platform must have Supabase OAuth credentials set up (handled by Simply Send — no action needed from you).
    Transactional domains only. Supabase auth emails must be sent from a Transactional domain. Marketing domains cannot be used for this integration.

    Removing the Connection

    There are two ways to stop routing Supabase auth emails through Simply Send.

    Option 1 — Delete from Simply Send

    Go to SMTP Credentials in your Simply Send dashboard and delete the credential labelled for the Supabase project (e.g. Supabase – your-project-ref). This removes Simply Send's side of the integration.

    • Deletes the SMTP credential from Simply Send
    • Connection record is removed
    • Supabase will fall back to its default email provider

    Option 2 — Disable from Supabase

    In your Supabase project, go to Settings → Auth → SMTP Settings and disable custom SMTP. Supabase will stop using Simply Send immediately.

    Note: The SMTP credential in Simply Send remains active but unused. Delete it manually from the SMTP Credentials page if you no longer need it.

    Security Notes

    How tokens are handled

    • The Supabase OAuth access token is used only during the configure step and is never persisted.
    • A refresh token is stored in encrypted form solely for the purpose of revoking access when you disconnect.
    • SMTP credentials are scoped per-connection and labelled for easy identification.
    • Disconnecting a Supabase project from Simply Send revokes the OAuth token and deletes the SMTP credential.

    Troubleshooting

    "Your authorization does not have permission to update this project"

    Ensure you are an Owner or Administrator on the Supabase project you selected. Member-level roles cannot modify Auth SMTP settings via the Management API.

    "Session expired or not found"

    The OAuth session is valid for 15 minutes. If it expires before you complete the Configure step, click Connect again to restart the flow.

    Connection limit reached

    You've hit your plan's Supabase connection limit. Upgrade to a paid plan or contact [email protected] to request a quota increase.

    Supabase emails still coming from the Supabase default sender

    Check that custom SMTP is enabled in Supabase Settings → Auth → SMTP. If you used the OAuth method, verify the connection shows as "Connected" on the Simply Send Integrations page.

    Auth emails failing after changing the Sender Email in Supabase

    The sender email (From Address) in Supabase must exactly match what was set during the Simply Send connection setup. The SMTP credential is bound to that specific address — if you change it in Supabase's Auth settings, Simply Send will reject the send. To use a different from address, delete the existing SMTP credential and reconnect with the new address.

    Need Help?

    If you run into issues connecting Supabase, our support team is here to help.

    Contact Support