Questions, answered.
Warmup
How long does warmup take?
Most new mailboxes need three to six weeks. Warmup starts at 10 emails a day and adds one a day up to 40, and inbox placement usually settles over the same stretch.
Should warmup keep running once I start sending campaigns?
Yes. Warmup runs alongside cold sending, so a dip in reputation shows up and gets corrected before your campaigns feel it.
What takes a mailbox out of the warmup pool?
A complaint rate of 0.10% or more, a bounce rate of 5% or more, or deleting and junking warmup mail it received. Landing in spam alone only slows warmup down until placement recovers.
Do the free and premium pools mix?
Only on proven terms. A paying mailbox can borrow free mailboxes that have been healthy members for at least three days, and a free mailbox only writes back to a paying inbox that wrote to it first.
Can I use Zexr only for warmup?
Yes. The free plan warms up to 10 mailboxes in the shared pool, and the Warmup plan covers every mailbox in the premium pool for $15 a month or $144 a year.
Sending
How many cold emails can one mailbox send?
50 a day by default, with a pause of 90 to 420 seconds before each send, drawn fresh every time. You can change it per mailbox up to 5,000, and the dashboard warns you past 100. Start a new mailbox at 10 to 20 a day and grow from there.
Do you rotate IP addresses?
No, on purpose. Your mailbox provider delivers your email from its own servers, so recipients never see Zexr’s address. What providers do notice is where your mailbox signs in from, so Zexr keeps that stable.
Can my sending be kept apart from other customers?
On Business and Enterprise, your mailboxes sign in to their providers from an address no other customer uses.
Which mailboxes can I connect?
Google Workspace and Gmail, Microsoft 365 and Outlook, and any mailbox with IMAP and SMTP, which covers iCloud, Zoho and most hosts.
Inbox and replies
How does Zexr know someone replied?
Replies are matched to the email they answer by its thread headers, even when the person writes back from another address. Out-of-office notices and autoresponders are recognised from their headers and never count as replies.
Can I see every mailbox in one place?
Yes. Every connected mailbox feeds one inbox, and you can narrow it to a mailbox, a tag or a label at any time.
Are open rates reliable?
More than most. Zexr counts people only: privacy proxies, link scanners and instant machine opens are kept as proof of delivery but never counted. Replies are still the better signal.
Security and data
Where is my data stored?
In AWS, in us-east-1 by default and eu-west-1 on Grow and Business. Enterprise can choose its own residency.
How are mailbox credentials stored?
Encrypted at rest with a dedicated credentials key, kept separate from the data key your workspace uses for message content and integration tokens. Plain keys are only ever held briefly in memory.
Do you have SOC 2?
A SOC 2 Type II audit is in progress. We can share a bridge letter once the report is issued.
Do you sign DPAs?
Yes. Email support@zexr.app and we turn it around within 48 hours.
Billing
Do you charge per email?
No. Each plan includes a daily send budget. Unused volume doesn’t carry over.
What is your refund policy?
A full refund within 14 days of a paid purchase if Zexr didn’t work for you.
Do you have startup pricing?
50% off Grow for a year for pre-seed and seed companies from YC, Antler, EF, Techstars and similar programmes.
Still stuck?
The docs go deeper than any answer here, and a person reads every message.
Still have a question?
Email the team or ask in Discord. A person reads every message.