Sender Domain Setup

Verifying your own sender domain tells email providers that Synapse is authorized to send on behalf of your domain, which improves deliverability and puts your brand on every email. It is an optional upgrade — you can go live and send on Synapse's shared pyrx.tech domain with no setup at all. This page is the full reference for DNS setup, verification, and troubleshooting for when you're ready to add your own domain.

For the quick-start walkthrough, see Set Up Sender Domain.

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Why Add a Custom Domain

You can send on Synapse's shared domain ([email protected]) on any plan, in both test and live mode, with nothing to configure. Verifying your own domain is an optional upgrade that adds three things for production sending:

• Higher trust. Recipients and email providers trust emails from your own domain more than a shared one.
• Your brand in the "From" address. Customers see yourcompany.com instead of pyrx.tech.
• Isolated reputation. Your sender reputation is your own, rather than pooled with other workspaces on the shared domain.

A custom domain gives you full control over your sender reputation and brand presentation. It is recommended for production, but it is not required to go live — you can add it any time, and until it verifies your sends continue to go out on the shared domain.

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Adding a Domain

1. Go to Settings > Sender Domains in the dashboard.
2. Click Add Domain.
3. Enter the domain name (e.g., yourcompany.com or mail.yourcompany.com).
4. Click Continue.

Synapse generates the DNS records you need to add to your domain's DNS configuration and automatically detects which DNS provider hosts your domain. The domain starts in Pending status until verification passes.

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DNS Provider Auto-Detection

When you add a domain, Synapse automatically detects your DNS provider and displays it with a branded icon on the domain detail page. The detected provider name links directly to your provider's DNS management panel, so you can jump straight to where you need to add records.

Supported Providers

Synapse recognizes the following DNS providers:

If your provider isn't in this list, Synapse shows it as "DNS Provider" and you can still set up your domain manually.

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DNS Records Explained

After adding your domain, Synapse provides four DNS records. Each serves a different purpose in email authentication:

1. SPF (Sender Policy Framework)

2. DKIM (DomainKeys Identified Mail)

3. DMARC (Domain-based Message Authentication)

4. Ownership Verification

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Adding Records to Your DNS Provider

Synapse detects your DNS provider automatically and shows a direct link to your provider's DNS management panel on the domain detail page. Click the provider name to open your DNS settings in a new tab.

If your provider is not auto-detected, use the general steps below.

General Steps

1. Log into your DNS provider.
2. Navigate to the DNS management page for your domain.
3. Add each record with the type, host, and value shown in the Synapse dashboard.
4. Save your changes.

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Auto-Configure with Cloudflare (Domain Connect)

If your domain uses Cloudflare nameservers, Synapse detects this automatically and offers one-click DNS setup via the Domain Connect protocol. This adds all required DNS records (SPF, DKIM, DMARC, and ownership verification) to your Cloudflare zone without any manual entry.

How It Works

1. Add your domain in Synapse. Synapse detects that it uses Cloudflare.
2. On the domain detail page, click the Auto configure button (shown with the Cloudflare icon).
3. You are redirected to Cloudflare's authorization page.
4. Click Authorize on Cloudflare to allow Synapse to add the DNS records.
5. You are redirected back to Synapse. The records are configured automatically.
6. Synapse auto-verifies the DNS records. Your domain shows as Verified with all records confirmed.

What Gets Configured

When you authorize Domain Connect, Cloudflare automatically adds all four DNS records:

• SPF TXT record
• DKIM CNAME record
• DMARC TXT record
• Ownership verification TXT record

If Auto-Configure Fails

If the authorization is cancelled or encounters an error, Synapse shows the failure on the domain detail page. You can:

• Retry by clicking the auto-configure button again.
• Fall back to manual setup by adding the DNS records yourself using the values shown in the dashboard.

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Verifying Your Domain

After adding the DNS records (either manually or via auto-configure):

1. Go to Settings > Sender Domains.
2. Click on your domain to open the detail page.
3. Click Verify.

Synapse checks each DNS record individually using DNS-over-HTTPS (via Cloudflare's public resolver). The detail page shows a per-record status:

Domain Status

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Troubleshooting DNS Issues

Verification keeps failing

• Check for typos. Copy values directly from the Synapse dashboard. Even an extra space or missing character will cause failure.
• Check for duplicates. Some providers already have an SPF or DMARC record. Having two SPF TXT records on the same host is invalid -- merge them.
• Check host format. Some providers want resend._domainkey, others want resend._domainkey.yourcompany.com. If one doesn't work, try the other.
• Check record type. Make sure the DKIM record is a CNAME, not a TXT. The SPF and DMARC records must be TXT, not CNAME.
• Wait for propagation. Allow at least 1 hour before retrying. Some providers (especially less common registrars) can take up to 48 hours.

Records show as verified but domain is still "Pending"

All four records must pass verification. Click into the domain detail page to see which specific record is still failing.

Auto-configure button not showing

• The auto-configure button only appears for domains hosted on Cloudflare. If your domain uses a different DNS provider, you need to add records manually.
• If your domain is on Cloudflare but the button doesn't appear, try refreshing the page. Synapse re-detects the DNS provider on each page load if it hasn't been cached yet.

Emails still going to spam after verification

• Allow 2-3 days for email providers to build trust with your new sending domain.
• Make sure your DKIM record is verified (not just SPF).
• Check that your email content isn't triggering spam filters (misleading subject lines, excessive links, etc.).
• Consider tightening your DMARC policy from p=none to p=quarantine once you're confident all legitimate emails pass SPF and DKIM.

I changed my DNS records and need to re-verify

1. Go to Settings > Sender Domains.
2. Click on the domain.
3. Click Verify to trigger a fresh DNS check.

Synapse will re-check all records and update each record's status individually.

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Deleting a Domain

If you no longer need a sender domain:

1. Go to Settings > Sender Domains.
2. Click on the domain.
3. Click Delete.

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Next Steps

• Set Up Sender Domain -- the quick-start walkthrough
• Write Your First Template -- start creating emails
• Workspace Settings -- configure your default sender identity