Synthesia uses Mailchimp for marketing email and SendGrid for transactional/notifications. They rank #11,771 in the Tranco list of most-popular domains. We've also observed sends via 3 other providers: HubSpot, Mailgun, Amazon SES. Email goes out from 5 different subdomains. Their email authentication setup is solid (score 100/100). We've recorded 4 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 3 emails we've observed. DMARC policy is read live from DNS.
DMARC reports sent to URIports. Policy
p=reject means receivers actively block or quarantine spoofed mail.
SPF alignment: all 19 observed emails use a return-path aligned with synthesia.io (bounces.synthesia.io, 8269203m.info.synthesia.io, em879.synthesia.io). SPF authenticates the visible From — supports DMARC directly.
DKIM alignment: all 19 observed emails sign with a domain aligned with synthesia.io (updates.synthesia.io, 8269203m.info.synthesia.io, synthesia.io). DKIM authenticates the visible From — supports DMARC directly.
VMC issued by: digicert.
TLS: 40% TLS 1.3, 60% TLS 1.2 (across 5 sends).
Delivery: fast — 100% of emails in the last 7 days arrive in under 10 seconds (across 3 sends).
Brands often use multiple ESPs (e.g. one for marketing, another for transactional/notifications).
HubSpot 8 Mailgun 3 Amazon SES 2ESPs 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: synthesia.io, bounces.synthesia.io, 8269203m.info.synthesia.io, 8269203t.synthesia.io, em879.synthesia.io, mailfrom.notifications.synthesia.io, updates.synthesia.io, info.synthesia.io, notifications.synthesia.io, notification-academy.synthesia.io
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 | 24 | 92.3% |
| spam | 2 | 7.7% |
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 % |
|---|---|---|---|---|---|
| Mailchimp | 6 | 83.3% | 0.0% | 16.7% | |
| HubSpot | 7 | 85.7% | 0.0% | 14.3% | |
| Mailgun | 3 | 100.0% | 0.0% | 0.0% | |
| Amazon SES | 2 | 100.0% | 0.0% | 0.0% | |
| SendGrid | 3 | 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 synthesia.io has been observed sending from, and where their mail landed in Gmail.
| IP | Hostname | Obs | Placement | Reputation |
|---|---|---|---|---|
| 198.2.134.84 | updates.synthesia.io |
13 | — | Check → |
| 158.247.26.209 | bid48bn.8269203m.info.synthesia.io |
7 | — | Check → |
| 168.245.8.45 | o2.email.sendoso.com |
3 | — | Check → |
| 141.193.32.11 | v511.v5ed9ac7d.euw1.send.eu.mailgun.net |
2 | 2 | Check → |
| 158.247.26.150 | bid4790.8269203t.synthesia.io |
1 | — | Check → |
| 143.55.232.46 | v546.v5f06b487.use4.send.mailgun.net |
1 | — | Check → |
| 54.240.7.24 | a7-24.smtp-out.eu-west-1.amazonses.com |
1 | — | Check → |
| 54.240.7.13 | a7-13.smtp-out.eu-west-1.amazonses.com |
1 | 1 | Check → |
