Provision
domains, mailboxes, DNS and authentication records.
Plimsoll is sending infrastructure with a ceiling you cannot raise.
Every domain gets a published daily maximum and a 21-day ramp. A model reads the replies no header rule can, and the ramp holds on anything that might be a complaint.
No card required.
The sequence worked for nineteen days.
By day twenty-four, four domains were in spam on Microsoft 365.
The tooling offered more mailboxes and raised volume the week two recipients asked to be removed.
$90
per domain per month, at one domain or forty
21 days
published ramp, the same schedule for everyone
1 in 6
replies a header rule cannot classify
Product
Replies decide how fast a domain climbs, and one in six needs a model
Ramp
a published 21-day climb to the ceiling.
Match by header
rules settle bounces, auto-responders and delivery failures.
Classify the rest
a model scores free text and quotes its sentence.
Hold
under the confidence floor, the ramp waits for a named reviewer.
Suppress
a removal request blocks the address on every domain, permanently.
Get started
The first three weeks, including the boring half
Most of it is DNS, and none of it is faster if you pay us more.
Steps 01–03
- 01Day one, domainsDNS and authentication records generated and checked
- 02Day one, the backfillmonths of your reply history read in one batch
- 03Day two, connectpoint your sequencing tool at the mailboxes
Steps 04–05
- 04Days two to twenty-twothe published ramp, pausing on any day a reply is held
- 05Day twenty-threethe domain reaches its ceiling and stays there
Reply reading
A misread complaint costs a domain, so the reply model holds when unsure
Free text
an unsubscribe that sounds interested, a forwarded complaint.
The verdict
a class, a confidence score and the deciding sentence.
Below the floor
the ramp holds until a named reviewer reads it.
Training
reviewed pairs, without identifiers, fine-tune our classifier unless you opt out.
A decision
There is no field for the daily cap
That field gets edited the day volume falls behind, which is also the day complaints climb.
Support cannot raise our ceiling, and neither can an annual contract.
We lose every buyer who wants more volume this quarter, and every page that compares capacity.
Where replies are read, and what we never take
- Free-text replies classified on Azure OpenAI in West US 3, nothing retained
- Prospect lists are never uploaded, stored or enriched here
- Sending and the reply store on cloud servers in Oregon
- Every reviewer read of a held reply is logged in your export
Reply bodies are the recipient's own words, which is why they do not leave the United States.
Not for
Where Plimsoll stops
- No unlimited plan. The ceiling is not a tier.
- No sequencer. Your own tool writes and schedules the campaign.
- No prospect data. We never sell, enrich or verify a list.
- A guaranteed ceiling. Inbox placement is never promised.
- One published ramp. Every customer gets the same 21 days.
- Permanent suppression. A removed address stays removed, after cancellation too.
Pricing
$90 per domain, per month
Mailboxes included with every domain, not sold by the unit
DNS and authentication setup, and the reply history backfill
Daily ceiling, ramp position, complaint rate and held-reply count by API
Reviewer time on every held reply, at no extra cost
Limits
How long Plimsoll holds things
1 business day
usual wait before a reviewer reads a held reply
180 days
reply bodies kept, then deleted
2 years
send metadata kept for deliverability questions
0
ways to raise a domain above its ceiling
FAQ
Before you hand over a domain
Can I pay to raise the ceiling?⌄
No.
Where is the ceiling published?⌄
Per domain type, in the API, before you provision anything.
Does my own sequencing tool work?⌄
Yes, over SMTP and IMAP to our mailboxes.
Do you register domains for me?⌄
Yes, or you bring your own.
Run one domain through the whole ramp for nothing
One work email. No card. Twenty-one days, and you keep the domain either way.
We reply within one business day.