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Cashflowdiary uses Substack as their primary email service provider. Their email authentication setup is solid (score 85/100).

Marketing ESPSubstack
Total observations26
Active days22
Avg per active day1.2
Last activity📬 Active · 2 days ago
Cadencealmost daily
Compare Cashflowdiary 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 1/10

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

Authentication

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

SPF alignment: observed emails use a third-party return-path (mg-d0.substack.com, mg-d1.substack.com, mg2.substack.com) — SPF passes there but doesn't align with cashflowdiary.substack.com, so DMARC has to rely on DKIM alignment.

DKIM alignment: observed emails sign with a third-party DKIM key (mg-d0.substack.com, mg-d1.substack.com, mg2.substack.com) — DKIM passes there but doesn't align with cashflowdiary.substack.com, so DMARC has to rely on SPF alignment.

Transport & deliverability

TLS: 0% TLS 1.3, 100% TLS 1.2 (across 20 sends).

🐢 Slow delivery observed

2 of 9 emails in the last 7 days were delayed beyond 5 minutes (22%) — delays stayed within 5–15 minutes. Slow sends averaged 10 min. Healthy senders deliver in under 30 seconds. Consistent delays usually mean greylisting, reputation-based throttling, or receiver-side filter scrutiny — worth investigating sender reputation and authentication setup.

Other ESPs detected

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

None — only the primary ESP(s) shown above

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.

Substack ✓ via Mailgun

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.

Mailgun

Probed: cashflowdiary.substack.com, mg2.substack.com, mg-d1.substack.com, mg-d0.substack.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 26 100.0%

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 %
Substack 26
100.0% 0.0% 0.0%

ESP activity over time

Jun 3 – Jun 28, 2026 · 23 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.

2 0 Substack: 2 (2026-06-03)2Substack: 1 (2026-06-06)1Substack: 1 (2026-06-07)1Substack: 1 (2026-06-08)1Substack: 1 (2026-06-09)1Substack: 1 (2026-06-10)1Substack: 1 (2026-06-11)1Substack: 1 (2026-06-12)1Substack: 1 (2026-06-13)1Substack: 1 (2026-06-15)1Substack: 1 (2026-06-16)1Substack: 1 (2026-06-17)1Substack: 1 (2026-06-18)1Substack: 1 (2026-06-19)1Substack: 1 (2026-06-20)1Substack: 1 (2026-06-21)1Substack: 1 (2026-06-22)1Substack: 2 (2026-06-23)2Substack: 1 (2026-06-24)1Substack: 1 (2026-06-25)1Substack: 1 (2026-06-26)1Substack: 2 (2026-06-27)2Substack: 1 (2026-06-28)106/0306/0606/0906/1206/1506/1806/2106/2406/27
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Substack

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Sending IPs

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

IPHostnameObsPlacementReputation
159.112.244.36 v536.v5375b7fa.use4.send.mailgun.net 3 3 Check →
69.72.47.244 mg-47-244.substack.com 2 1 Check →
159.112.244.42 v542.v5375b7fa.use4.send.mailgun.net 2 Check →
159.112.244.43 v543.v5375b7fa.use4.send.mailgun.net 2 2 Check →
159.112.244.47 v547.v5375b7fa.use4.send.mailgun.net 1 Check →
161.38.201.184 v5184.v5075e2e3.usw1.send.mailgun.net 1 Check →
159.112.244.14 v514.v5375b7fa.use4.send.mailgun.net 1 Check →
159.112.244.57 v557.v5375b7fa.use4.send.mailgun.net 1 Check →
159.112.244.53 v553.v5375b7fa.use4.send.mailgun.net 1 Check →
159.112.244.4 v54.v5375b7fa.use4.send.mailgun.net 1 Check →
161.38.202.170 mg-202-170.substack.com 1 Check →
161.38.201.123 v5123.v5075e2e3.usw1.send.mailgun.net 1 Check →
161.38.201.122 v5122.v5075e2e3.usw1.send.mailgun.net 1 Check →
159.112.244.18 v518.v5375b7fa.use4.send.mailgun.net 1 Check →
159.112.244.3 v53.v5375b7fa.use4.send.mailgun.net 1 Check →
161.38.199.249 mg-199-249.static.mg-d0.substack.com 1 1 Check →
159.112.244.34 v534.v5375b7fa.use4.send.mailgun.net 1 1 Check →
143.55.229.171 v5171.v56063cb6.use4.send.mailgun.net 1 1 Check →
159.112.244.58 v558.v5375b7fa.use4.send.mailgun.net 1 1 Check →
159.112.244.7 v57.v5375b7fa.use4.send.mailgun.net 1 1 Check →
143.55.229.170 v5170.v56063cb6.use4.send.mailgun.net 1 1 Check →

Sending domains

DomainESPs detectedDelivery (7d)
cashflowdiary.substack.comSubstack 26🐢 2/9 slow (avg 10 min)