Good deliverability means your emails actually land in inboxes, not spam folders. This guide covers how Stardex sends emails, what impacts deliverability, and how to get the best results from your outreach campaigns.
When you connect your Gmail or Outlook account to Stardex, you grant us OAuth permission to send emails on your behalf. This means Gmail (or Outlook) is the actual sender — we simply tell it when to send and to whom. Your emails go out from your real inbox, show up in your sent folder, and replies come back to you directly.
This is different from tools that use their own SMTP servers to send emails. With SMTP-based sending, emails are routed through a third-party server, which mailbox providers can flag as suspicious — especially if unsubscribe headers or proper authentication aren't included. Because Stardex sends through your actual mailbox, your emails are treated the same as if you hit send yourself in Gmail.
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Stardex is built for low-volume, high-quality outreach — the kind that executive search firms and recruiters do daily. If you need to send more than a few hundred emails a day from a single inbox, we recommend dedicated cold email tools like Instantly or Smartlead which are built for that scale.
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Even though Stardex sends through your real inbox, deliverability still depends on a few key factors.
These are DNS records that prove your domain is legitimate. Gmail, Outlook, and Yahoo now strictly enforce these — emails that fail authentication checks get rejected outright, not just sent to spam.
Most Google Workspace and Microsoft 365 accounts have SPF and DKIM configured by default. DMARC you may need to set up manually. Ask your IT admin or domain provider to confirm all three are in place.
Quick check: Use mail-tester.com to send a test email and see if your authentication is set up correctly. If something's off, it'll tell you exactly what to fix.
This is the biggest factor you can actually control. Gmail and Outlook track how many emails you send per day, and if you send too many too fast, their spam filters kick in — regardless of how the email was sent.
Recommended daily limits based on domain age:
| Domain Age | Recommended Max Emails/Day |
|---|---|
| Less than 3 months | 15–25 |
| 3–12 months | 25–50 |
| 1–3 years | 50–100 |
| 3+ years (established) | 100–300 |
These are per inbox. If you're just getting started with a new domain, keep it low and ramp up gradually over a few weeks. If your firm has been around for 5–10 years and your domain has solid history, you have more room — but we still wouldn't recommend pushing past 200–300/day from a single inbox.
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These limits include all emails from your inbox — campaigns, follow-ups, and regular day-to-day emails. Keep that in mind when planning your outreach volume.
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