Apollo.io sequences: seeds over scores

Apollo.io sits at an unusual intersection. It is a prospecting database with a sending engine bolted on, rather than a sending tool that bought data. That split matters for deliverability. Apollo's sequence feature uses your connected mailbox — Gmail, Microsoft 365, or SMTP — to send, so your domain authentication and mailbox reputation drive placement. Apollo's own Deliverability Score gives you a pool-level view. What it cannot give you is per-provider, per-campaign, per-send placement. That is what seeds are for.

How Apollo routes your sequence

Apollo sends on your behalf through your connected mailbox using either the Gmail/Google Workspace API, the Microsoft Graph API, or direct SMTP for custom mail. This means:

• The authenticated domain on the seed's Authentication-Results header is yours, not Apollo's.
• Sending IP is your mailbox provider's (Google/Microsoft shared pools, typically).
• Apollo injects open tracking pixels and click-tracking links when enabled. Both are visible to spam filters.
• The DKIM selector on the header is whatever selector your mailbox signs with (e.g. google._domainkey).

What that means for seed testing: the results you see reflect your authentication setup plus the impact of Apollo's tracking injection. If you want to isolate the Apollo impact, send one seed test with tracking off and one with tracking on, and compare.

Adding seeds to an Apollo sequence

1. Generate 20+ seed addresses with the free Inbox Check tool.
2. In Apollo, open your sequence → Contacts → Add contacts.
3. Choose Add manually or Upload CSV. If you use CSV, map the email column and set first name to a realistic value. Apollo will reject contacts without a reasonable first name for some sequence templates.
4. Give each seed a custom tag (seed) in Apollo's contact record. This lets you filter seeds out of reporting.
5. Save. Seeds enter the sequence on the same cadence as live prospects.

A common Apollo-specific gotcha: if your sequence uses "send on behalf of" rules (where one rep sends for another), the From header and the DKIM signing domain can diverge, which kills DMARC alignment. Seed tests catch this on the first send.

Apollo's Deliverability Score vs seed placement

Apollo's in-app Deliverability Score is computed from a bundle of signals: SPF/DKIM/DMARC setup, sending volume patterns, bounce rate, spam complaint rate pulled from Postmaster Tools where connected, and aggregate sequence performance. It is a single number, usually in the 0 to 100 range, sometimes colour-coded.

It is useful. It is also the wrong tool for the "did my sequence land at Outlook today" question. Reasons:

• It is a rolling aggregate. Today's drop at Outlook is averaged with last week's healthy send, so it looks fine.
• It treats providers equally. 95% Inbox at Gmail and 20% Inbox at Outlook averages to a score that looks acceptable.
• It does not see Mail.ru or Yandex. If your ICP is in Russia or CIS, the score is blind to your biggest audience.
• It lags. Postmaster Tools data arrives with 24 to 48 hours delay.

Seeds answer a sharper question: "right now, where does my sequence step 1 land at each specific provider?" The two signals are complementary. Score trending down while seeds look fine = domain reputation issue building. Seeds landing in Spam while score still looks fine = immediate copy/content issue that the score has not caught up to.

Cross-referencing the two in practice

The weekly routine we recommend for a serious Apollo user:

1. Every Monday, run a seed test on each live sequence's next step.
2. Screenshot Apollo's Deliverability Score.
3. Build a short note: seed Inbox rate vs Apollo Score. Keep the note in a shared doc or spreadsheet.
4. Watch for divergence. If seed Inbox rate drops 10+ points week over week while Apollo Score holds steady, trust the seeds and investigate. The score will catch up in 5 to 7 days.
5. If Apollo Score drops 10+ points while seeds still look good, check Postmaster Tools directly. Usually a complaint spike from one sequence template.

Apollo-specific fixes when seeds go bad

When a seed test shows step 2 landing in Outlook Junk, Apollo gives you several levers:

• Disable link tracking on that step. Retest. If placement recovers, the tracking domain is the issue — set up a custom one in Apollo settings.
• Disable open tracking on the same step. Retest. If placement recovers, the pixel is getting flagged.
• Check "send as plain text". Apollo defaults to HTML even when the visible content is plain text. A text-only cold email sent as HTML scores worse than one sent as text/plain.
• Review dynamic fields. Apollo's {{company_name}} token can render as an empty string when the company record is sparse. Broken placeholders are a strong spam signal.

Frequently asked questions