Notion uses Customer.io as their primary email service provider. They rank #1,060 in the Tranco list of most-popular domains. We've also observed sends via Marketo. Email goes out from 2 different subdomains. Their email authentication setup is solid (score 95/100). We've recorded 3 ESP changes since first observing this brand.
Authentication signals observed in this brand's emails. SPF, DKIM and DMARC are the standard sender-authentication stack — see the DMARC policy below for whether spoofing is actually blocked or just monitored. One-click unsubscribe meets Google & Yahoo's bulk-sender requirements.
SPF / DKIM / DMARC above reflect the last 5 emails we've observed. DMARC policy is read live from DNS.
DMARC reports sent to DMARC Digests. Policy
p=quarantine means receivers actively block or quarantine spoofed mail.
DKIM alignment: all 32 observed emails sign with a domain aligned with notion.so (mail.notion.so, hello.notion.so). DKIM authenticates the visible From — supports DMARC directly.
VMC issued by: digicert.
TLS: 23% TLS 1.3, 77% TLS 1.2 (across 13 sends).
Brands often use multiple ESPs (e.g. one for marketing, another for transactional/notifications).
Marketo 6ESPs we've seen sending email for this brand. Green = confirmed by SPF, sender IP rDNS, or known infra pairing (label shows the source). Grey = observed but not yet confirmed by SPF or PTR.
ESPs this brand has authorized in their SPF record. We confirm them with a green ✓ only after seeing recurring use (3+ emails across 2+ days). Until then they stay here — either we haven't observed any email yet, or we've seen a handful but not enough to call them a regular sender for the brand.
Probed: notion.so, mail.notion.so, hello.notion.so
Folder distribution across all emails from this brand observed in Gmail inboxes. High inbox % = good deliverability; spam appearances are the headline signal.
| Folder | Count | Share |
|---|---|---|
| inbox | 46 | 95.8% |
| promotions | 2 | 4.2% |
Which ESP's emails are landing where. Sorted by spam % so problem senders surface first. Brands using one ESP for marketing and another for transactional often see very different placement profiles per ESP. Per-ESP folder data only started being captured recently — counts here may be smaller than the total above until backfill catches up.
| ESP | Emails | Placement | Inbox % | Tabs % | Spam % |
|---|---|---|---|---|---|
| Marketo | 5 | 100.0% | 0.0% | 0.0% | |
| Customer.io | 41 | 95.1% | 4.9% | 0.0% |
Daily observations per ESP. Brands often run multiple ESPs concurrently — marketing on one, transactional on another — so this chart shows usage rather than switches.
IP addresses notion.so has been observed sending from, and where their mail landed in Gmail.
| IP | Hostname | Obs | Placement | Reputation |
|---|---|---|---|---|
| 143.55.229.27 | outgoing1.mail.notion.so |
12 | — | Check → |
| 143.55.229.30 | outgoing4.mail.notion.so |
10 | 1 | Check → |
| 199.15.214.22 | hello.notion.so |
6 | 3 | Check → |
| 143.55.229.26 | outgoing0.mail.notion.so |
6 | — | Check → |
| 143.55.229.31 | outgoing5.mail.notion.so |
6 | — | Check → |
| 143.55.229.28 | outgoing2.mail.notion.so |
5 | 1 | Check → |
| 143.55.229.29 | outgoing3.mail.notion.so |
3 | — | Check → |
| Domain | ESPs detected | Delivery (7d) |
|---|---|---|
mail.notion.so | Customer.io 42 | |
hello.notion.so | Marketo 6 |