Connect SMTP to send Fileflare’s download emails from your own domain instead of Fileflare’s default noreply@digital-downloads.com. Customers see your store’s name in their inbox, deliverability improves with proper domain authentication, and you can use any SMTP-compatible service — Postmark, Brevo, Resend, MailerSend, Mailtrap, SendGrid, or your own mail server.
Available on the Premium plan and higher. You’ll need a domain you control (so you can verify ownership with the SMTP provider) and a few minutes to copy SMTP credentials between two tabs. Plan to spend an extra 30 minutes if you want to set up DKIM/SPF/DMARC for best deliverability — see Improve email deliverability.
When you’d use this
- You want emails to come from
files@yourstore.cominstead of Fileflare’s default address. - You’re noticing emails landing in spam from the default sender — your own authenticated domain typically improves placement.
- You want analytics from your SMTP provider (open rates, click tracking) on top of Fileflare’s email tracking.
- You want full control of your email sending infrastructure (volume, IP, reputation).
Pick a provider
All these providers work with Fileflare. The decision usually comes down to deliverability, free-tier limits, and how technical you want to get. Quick guidance:
- Postmark — best overall. Excellent deliverability, simple setup, 100 emails/day free, paid from $15/mo. Recommended.
- Resend — modern, developer-friendly. Generous free tier, easy domain verification.
- Brevo (formerly Sendinblue) — easy to set up, 300 emails/day free. Note: Brevo’s link tracking can break Fileflare’s signed URLs — disable it in Brevo’s settings.
- MailerSend — solid free tier, clean dashboard.
- Mailtrap — good for testing; production use also works.
- SendGrid — works fine but no longer has a free tier; SMTP API has a 5,000-email lifetime cap per key.
- Your own mail server (Outlook, Yahoo, custom) — possible but more limited (Google Workspace SMTP is no longer available to new users; daily limits are tight on most personal accounts).
General SMTP setup
The exact button labels differ by provider, but the flow is the same:
- Sign up for the SMTP provider.
- Verify your domain so the provider can send mail on its behalf. Usually involves adding a few DNS records.
- Generate an SMTP credential (username + password, or an API key used as both).
- In Fileflare → Settings → Emails → choose SMTP, paste the host, port, username, password, and a sender email.
- Click Save. Fileflare sends a verification email to your sender address — click the verify link to confirm.

Provider-specific setup
Below: provider-specific credentials and where to find them.
Postmark (recommended)
- Free tier: 100 emails/day, up to 3,000/month
- Paid from: $15/mo for 10k emails
- Verification: 1–24 hours (typically 1–2)
- Notes: Postmark hand-verifies new accounts to maintain their sender reputation, which is part of why deliverability is so good. Worth the wait.
Setup
- Sign up for Postmark.
- Go to Sender Signatures → Add domain or signature. Verify your domain (preferred over single email).
- Open your server → API Tokens → Create API Key.
- Copy the API key. In Fileflare’s SMTP settings, paste it into both Username and Password.
- Set Host:
smtp.postmarkapp.com, Port:587(try25or2525if 587 is blocked), Encryption:TLS. - Set Sender to any email address on your verified domain.
- Save and click the verification link Fileflare emails you.
Resend
- Free tier: 3,000 emails/month, 100/day
- Paid from: $20/mo for 50k emails
- Notes: Modern API-first provider. Great DX, fast onboarding.
Setup
- Sign up for Resend.
- Go to Domains → Add Domain. Add the suggested DNS records to your domain.
- Wait for the domain to show as verified.
- Go to API Keys → Create API Key. Copy it.
- In Fileflare, set Host:
smtp.resend.com, Port:587, Username:resend, Password: your API key, Encryption:TLS, Sender: any address on your verified domain. - Save and verify.
Brevo (formerly Sendinblue)
- Free tier: 300 emails/day
- Paid from: $8/mo for 5k emails
- Important: Brevo’s automatic link tracking will rewrite Fileflare’s download URLs and break them, causing customers to see “Invalid HMAC” errors. Disable link tracking in Brevo before going live.
Setup
- Sign up for Brevo.
- Top-right profile → Senders, Domains & Dedicated IPs → Domains → Add domain. Brevo has one-click verification for many domain providers.
- Go to Transactional → Settings → Configuration → SMTP relay.
- Click Generate a new SMTP key. Copy the login and the key.
- In Fileflare, set Host:
smtp-relay.brevo.com, Port:587, Username: Brevo’s login, Password: Brevo’s SMTP key, Encryption:TLS, Sender: any address on your verified domain. - Save and verify.
- Important: in Brevo, disable click/link tracking to prevent broken download links.
MailerSend
- Free tier: 3,000 emails/month
- Paid from: $30/mo for 50k emails
- Notes: Clean modern dashboard, solid deliverability.
Setup
- Sign up for MailerSend.
- Go to Domains → add your domain. Add the DNS records they provide.
- Once verified, go to Email → SMTP → generate SMTP credentials.
- In Fileflare, set Host:
smtp.mailersend.net, Port:587, Username and Password: from MailerSend’s SMTP page, Encryption:TLS, Sender: any address on your verified domain. - Save and verify.
Mailtrap
- Free tier: 1,000 emails/month
- Paid from: $10/mo for 10k emails
- Notes: Best known for email testing; production sending also works fine.
Setup
- Sign up for Mailtrap and choose Email Sending (not the testing inbox).
- Add and verify your domain via DNS records.
- Open Sending Domains → your domain → SMTP/API integration.
- Copy the SMTP credentials they show.
- In Fileflare, set Host:
live.smtp.mailtrap.io, Port:587, Username:api, Password: your API token, Encryption:TLS, Sender: any address on your verified domain. - Save and verify.
SendGrid
- Free tier: none (free plan retired)
- Paid from: $19.95/mo for 50k emails
- Important: SendGrid’s SMTP API key has a 5,000-email lifetime cap. Once you hit it, the key stops working — you’ll need to regenerate. For high volume, consider Postmark or MailerSend instead, or use SendGrid’s regular API once Fileflare supports it directly.
- Also: disable click tracking in SendGrid (Settings → Tracking → Click tracking) — it rewrites Fileflare’s download URLs and breaks them.
Setup
- Sign up for SendGrid.
- Verify a sender domain via Sender Authentication (Settings → Sender Authentication → Authenticate Your Domain).
- Create an API key (Settings → API Keys → Create API Key) with full access. Copy it.
- In Fileflare, set Host:
smtp.sendgrid.net, Port:587, Username:apikey(literally the word), Password: your API key, Encryption:TLS, Sender: an email on your verified domain. - Save and verify.
- Important: disable click tracking in SendGrid before sending real customer emails.
Other providers (Outlook, Yahoo, custom)
Most ESPs provide SMTP credentials. The pattern is the same: get host, port, username, password from your provider, paste into Fileflare. A few specifics:
- Outlook / Hotmail: host
smtp-mail.outlook.com, port587, TLS, your full email + an app password. Limit: ~300 emails/day. - Yahoo: host
smtp.mail.yahoo.com, port587, TLS, your full email + an app password generated from Account Security. - Google Workspace: Google has stopped SMTP access for new users. Use Postmark or another provider instead.
Common issues
- “Invalid HMAC” error in customer download links — your SMTP provider is rewriting URLs for click tracking. Disable click/link tracking in the provider’s settings. (Especially Brevo and SendGrid.)
- Verification email never arrives — check spam, then double-check the host, port, username, and password are correct. Then check your provider’s dashboard for “blocked sends” or domain verification issues.
- “Domain not verified” error from the provider — DNS changes can take up to 48 hours to propagate. Most providers re-check on demand from their dashboard. If your domain has DNSSEC, some providers don’t auto-detect — try manual re-check.
- Emails work in test but not for real orders — make sure the Sender address you set in Fileflare is on the verified domain. Mismatched sender = silent rejection.
- SendGrid SMTP stopped working after a few thousand sends — you’ve hit the 5,000-email lifetime SMTP key cap. Generate a new API key and update Fileflare with it. (Or migrate to a provider without this limit.)
- Connection timeout on port 587 — some networks block 587. Try ports 25 or 2525. Postmark especially supports both fallbacks.
- Customers see emails in spam — set up DKIM, SPF, and DMARC. See Improve email deliverability for the full setup.