Inboxmonster uses Customer.io for marketing email and Amazon SES for transactional/notifications. Email goes out from 3 different subdomains. Their email authentication setup is solid (score 95/100). We've recorded 2 ESP changes since first observing this brand.
Amazon SESAuthentication 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 10 emails we've observed. DMARC policy is read live from DNS.
DMARC reports sent to inboxmonster.com. Policy
p=quarantine means receivers actively block or quarantine spoofed mail.
SPF alignment: 32% of observed emails use an aligned return-path (cio142873.mail.inboxmonster.com, outbound.intercom.inboxmonster.com); the rest use third-party paths (us-east-2.amazonses.com) where DMARC has to rely on DKIM alignment.
DKIM alignment: all 31 observed emails sign with a domain aligned with inboxmonster.com (app.inboxmonster.com, cio142873.mail.inboxmonster.com, inboxmonster.com). DKIM authenticates the visible From — supports DMARC directly.
VMC issued by: digicert.
TLS: 79% TLS 1.3, 21% TLS 1.2 (across 24 sends).
Delivery (last 7 days): 77% under 10 seconds, 15% over 1 minute (across 13 sends).
Brands often use multiple ESPs (e.g. one for marketing, another for transactional/notifications).
Intercom 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: inboxmonster.com, us-east-2.amazonses.com, cio142873.mail.inboxmonster.com, outbound.intercom.inboxmonster.com, app.inboxmonster.com, mail.inboxmonster.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 | 29 | 100.0% |
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 % |
|---|---|---|---|---|---|
| Amazon SES | 20 | 100.0% | 0.0% | 0.0% | |
| Customer.io | 9 | 100.0% | 0.0% | 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 inboxmonster.com has been observed sending from, and where their mail landed in Gmail.
| IP | Hostname | Obs | Placement | Reputation |
|---|---|---|---|---|
| 54.240.96.8 | a96-8.smtp-out.us-east-2.amazonses.com |
9 | 6 | Check → |
| 54.240.115.195 | a115-195.smtp-out.us-east-2.amazonses.com |
6 | 4 | Check → |
| 54.240.96.9 | a96-9.smtp-out.us-east-2.amazonses.com |
6 | 1 | Check → |
| 159.112.243.54 | v554.v5be21903.use4.send.mailgun.net |
5 | 4 | Check → |
| 198.244.52.4 | a4.a355d2fe.use4.send.mailgun.net |
3 | 3 | Check → |
| 147.253.214.240 | mta-253-214-240.intercom.com.sparkpostmail.com |
1 | — | Check → |
| Domain | ESPs detected | Delivery (7d) |
|---|---|---|
app.inboxmonster.com | Amazon SES 21 | |
mail.inboxmonster.com | Customer.io 9 | |
inboxmonster.com | Intercom 1 |