Tremendous uses HubSpot for marketing email and SendGrid for transactional/notifications. They rank #102,392 in the Tranco list of most-popular domains. Email goes out from 2 different subdomains. Their email authentication setup is good (score 80/100). We've recorded 5 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 10 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.
SPF alignment: 90% of observed emails use an aligned return-path (em1939.tremendous.com, em6429.reward.tremendous.com); the rest use third-party paths (bf05x.hubspotemail.net) where DMARC has to rely on DKIM alignment.
DKIM alignment: all 40 observed emails sign with a domain aligned with tremendous.com (tremendous.com, reward.tremendous.com). DKIM authenticates the visible From — supports DMARC directly.
TLS: 71% TLS 1.3, 29% TLS 1.2 (across 14 sends).
Delivery: fast — 100% of emails in the last 7 days arrive in under 10 seconds (across 8 sends).
Brands often use multiple ESPs (e.g. one for marketing, another for transactional/notifications).
Zendesk 12ESPs 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.
"Observed" pills mean we detected emails from these ESPs, but they don't appear in any SPF record we probed. They may still be properly authorized — sending infrastructure can live on subdomains we haven't seen yet, or use IP-listing instead of include: directives.
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: tremendous.com, em6429.reward.tremendous.com, em1939.tremendous.com, bf05x.hubspotemail.net, reward.tremendous.com, mailer.tremendous.com, ptr932.tremendous.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 | 42 | 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 % |
|---|---|---|---|---|---|
| SendGrid | 24 | 100.0% | 0.0% | 0.0% | |
| HubSpot | 4 | 100.0% | 0.0% | 0.0% | |
| Zendesk | 10 | 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 tremendous.com has been observed sending from, and where their mail landed in Gmail.
| IP | Hostname | Obs | Placement | Reputation |
|---|---|---|---|---|
| 168.245.39.134 | o2.mailer.tremendous.com |
21 | 4 | Check → |
| 192.254.118.203 | o4.mailer.tremendous.com |
13 | 3 | Check → |
| 159.183.107.130 | o5.ptr932.tremendous.com |
6 | 1 | Check → |
| 192.161.149.7 | unknown |
6 | — | Check → |
| 192.161.149.5 | unknown |
3 | — | Check → |
| 158.247.24.104 | bid47ui.bf05x.hubspotemail.net |
3 | 3 | Check → |
| 192.161.149.13 | unknown |
2 | — | Check → |
| 192.161.149.15 | unknown |
1 | — | Check → |
| 54.174.52.142 | pgg15c.bf05x.hubspotemail.net |
1 | — | Check → |