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Rb2b uses SendGrid as their primary email service provider. They rank #355,620 in the Tranco list of most-popular domains. We've also observed sends via Amazon SES. Their email authentication setup is solid (score 85/100). We've recorded 1 ESP change since first observing this brand.

Transactional ESPSendGrid
Total observations18
Active days8
Avg per active day2.3
Last activity📬 Active · 5 days ago
Cadence~every 4 days
Compare Rb2b with another brand:

Email setup 85/100

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.

Strong email setup
Authentication is in good shape — SPF, DKIM, and DMARC enforcement all configured.
85/100
SPF
pass
DKIM
pass
DMARC
pass (reject)
BIMI
none
Unsubscribe
one-click
SPF lookups 4/10

SPF / DKIM / DMARC above reflect the last 10 emails we've observed. DMARC policy is read live from DNS.

Authentication

DMARC reports sent to vali.email. Policy p=reject means receivers actively block or quarantine spoofed mail.

SPF alignment: all 18 observed emails use a return-path aligned with rb2b.com (outbound.intercom.rb2b.com, em4021.rb2b.com, bounce.rb2b.com). SPF authenticates the visible From — supports DMARC directly.

DKIM alignment: all 18 observed emails sign with a domain aligned with rb2b.com (rb2b.com). DKIM authenticates the visible From — supports DMARC directly.

Transport & deliverability

TLS: 62% TLS 1.3, 38% TLS 1.2 (across 13 sends).

Delivery (last 7 days): 75% under 10 seconds, 0% over 1 minute (across 8 sends).

Other ESPs detected

Brands often use multiple ESPs (e.g. one for marketing, another for transactional/notifications).

Intercom 7 Amazon SES 5

Confirmed senders

ESPs 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.

Amazon SES ✓ confirmed SendGrid ✓ confirmed Intercom ✓ via SparkPost

Other SPF authorizations

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.

Google Workspace SparkPost

Probed: rb2b.com, em4021.rb2b.com, outbound.intercom.rb2b.com, bounce.rb2b.com

Where emails landed (Gmail)

Folder distribution across all emails from this brand observed in Gmail inboxes. High inbox % = good deliverability; spam appearances are the headline signal.

FolderCountShare
inbox 18 100.0%

Placement by ESP

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 5
100.0% 0.0% 0.0%
Intercom 7
100.0% 0.0% 0.0%
SendGrid 6
100.0% 0.0% 0.0%

ESP activity over time

May 30 – Jun 26, 2026 · 8 days with sends

Daily observations per ESP. Brands often run multiple ESPs concurrently — marketing on one, transactional on another — so this chart shows usage rather than switches.

6 0 SendGrid: 1 (2026-05-30)1Intercom: 1 (2026-06-04)1Intercom: 2 (2026-06-05)SendGrid: 2 (2026-06-05)4SendGrid: 2 (2026-06-15)2Intercom: 1 (2026-06-16)1Intercom: 1 (2026-06-22)1Intercom: 2 (2026-06-25)SendGrid: 1 (2026-06-25)Amazon SES: 3 (2026-06-25)6Amazon SES: 2 (2026-06-26)205/3006/0206/0506/0806/1106/1406/1706/2006/2306/26
Intercom SendGrid Amazon SES

Similar brands using SendGrid

Sending IPs

IP addresses rb2b.com has been observed sending from, and where their mail landed in Gmail.

IPHostnameObsPlacementReputation
149.72.69.93 o1.ptr8578.getemails.com 6 1 Check →
192.174.84.116 mta-174-84-116.intercom.com.sparkpostmail.com 3 Check →
54.240.61.166 a61-166.smtp-out.us-west-2.amazonses.com 3 3 Check →
192.174.84.115 mta-174-84-115.intercom.com.sparkpostmail.com 2 1 Check →
54.240.42.185 a42-185.smtp-out.amazonses.com 2 2 Check →
192.174.84.114 mta-174-84-114.intercom.com.sparkpostmail.com 2 2 Check →

Sending domains

DomainESPs detectedDelivery (7d)
rb2b.comIntercom 7 SendGrid 6 Amazon SES 5