Close uses Customer.io for marketing email and SendGrid for transactional/notifications. They rank #29,166 in the Tranco list of most-popular domains. Email goes out from 2 different subdomains. Their email authentication setup is solid (score 95/100). We've recorded 1 ESP change 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 4 emails we've observed. DMARC policy is read live from DNS.
DMARC enforced with p=quarantine — receivers actively reject or quarantine spoofed mail. No aggregate reporting destination configured.
SPF alignment: all 21 observed emails use a return-path aligned with close.com (em3715.close.com, cio880.email.close.com). SPF authenticates the visible From — supports DMARC directly.
DKIM alignment: all 18 observed emails sign with a domain aligned with close.com (close.com, cio880.email.close.com). DKIM authenticates the visible From — supports DMARC directly.
VMC issued by: digicert.
TLS: 50% TLS 1.3, 50% TLS 1.2 (across 6 sends).
Brands often use multiple ESPs (e.g. one for marketing, another for transactional/notifications).
Zendesk 1ESPs 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: close.com, em3715.close.com, cio880.email.close.com, email.close.com
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 | 17 | 77.3% |
| promotions | 5 | 22.7% |
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 % |
|---|---|---|---|---|---|
| SendGrid | 16 | 68.8% | 31.3% | 0.0% | |
| Zendesk | 1 | 100.0% | 0.0% | 0.0% | |
| Customer.io | 5 | 100.0% | 0.0% | 0.0% |
Weekly 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 close.com has been observed sending from, and where their mail landed in Gmail.
| Domain | ESPs detected | Delivery (7d) |
|---|---|---|
close.com | SendGrid 18 Customer.io 1 Zendesk 1 | |
email.close.com | Customer.io 7 |