Teams that grow sequence volume in HubSpot usually hit the same wall: the more emails go out per day, the worse they land. Doubling sequence enrollments doesn't mean sending twice as many emails tomorrow. Done wrong, that's the fastest way to end up in the Gmail or Outlook spam folder - and HubSpot's default limits won't stop you from getting there.
Throttling means deliberately controlling send pace: how many emails go out per mailbox per day, how much time sits between sequence steps, and how enrollment volume is spread across reps. In HubSpot specifically, this matters because the platform's built-in limits are designed to keep the system from breaking, not to protect the reputation of any one domain or mailbox.
Gmail and Microsoft evaluate sender behavior over time, not one email at a time. A sharp jump in volume triggers the same red flags regardless of how good the copy is:
Sender reputation is built on the domain and the sending IP, not on a single campaign. One aggressive week can undo months of clean sending.
HubSpot separates two types of send limits:
Both apply on a rolling 24-hour window, not a fixed reset time, and both sit on top of your email provider's own limits - Gmail tops out around 500/day (100 if sending via SMTP), Google Workspace around 2,000/day (500 on a trial), and Microsoft 365 around 10,000 recipients/day. HubSpot can't push volume past whatever your provider allows underneath it.
Users with a Sales or Service Hub Professional seat can send up to 500 emails per day per connected inbox. On Sales Hub Professional or Enterprise, you can also set a custom daily send limit, either per day or per minute, and that custom limit overrides both the provider limit and the subscription's default sequences limit. This is the actual lever for building throttling into HubSpot - the default cap protects the infrastructure, the custom limit is what protects a specific mailbox's reputation.
Bulk enrollment itself has a hard ceiling too: HubSpot processes bulk sequence enrollments at a maximum of 3 emails per minute, which naturally spaces out large enrollments - but it won't stop you from enrolling far more contacts in a day than a young domain can safely handle.
What HubSpot does not do for you:
That layer has to be built on top of HubSpot's native settings.
There's no single safe number - it depends on domain age, sending history, and how warm the audience is. These ranges work as a starting point for most B2B teams:
New domain or new mailbox (first 0–4 weeks):
Warmed-up domain (1–6 months of consistent sending):
Established domain (6+ months, clean reputation):
The custom send limit setting is what makes these ranges enforceable - without it, a rep or a workflow can enroll far more contacts than the mailbox should handle in a day, and HubSpot will happily queue and send them up to its own default ceiling.
Throttling isn't only about daily volume. The gap between sequence steps affects deliverability just as much:
Teams that rush to close out a sequence faster are usually trading a slightly quicker first contact for worse deliverability across the whole list.
As a sales team grows and more reps enroll contacts into sequences, load distribution becomes its own problem:
Throttling isn't a one-time setup - it's an ongoing check. HubSpot's Sequences tool has an Email limit and usage report under the Scheduled tab that shows the percentage of the daily limit used, total sends, and sends remaining. Beyond that report, track:
Manual throttling means constantly watching who gets enrolled and when - especially when leads come in from multiple sources: forms, deals, imports. FlowNer automates sequence enrollment in HubSpot based on triggers, such as when a contact becomes a Lead or when a contact associated with a deal meets specific criteria. That keeps enrollment tied to real, time-distributed events instead of large manual list uploads, which is exactly the kind of sudden volume spike that puts a mailbox's reputation at risk. Teams building throttling into their process usually end up moving enrollment logic into workflows rather than manually selecting contact lists batch by batch - you can find the step-by-step setup here.
This also matters for teams that don't want to pay for a Sales Hub Enterprise seat per sender just to unlock workflow-based enrollment - there's a breakdown of what that actually costs for a small team here.
Does HubSpot throttle sequences automatically?
HubSpot enforces a daily send limit per connected inbox and processes bulk enrollments at a maximum of 3 emails per minute, but it doesn't adjust limits based on domain age or pause enrollment when bounce or spam complaint rates rise. That requires a custom send limit and separate monitoring.
What's the difference between the HubSpot send limit and the Sequences daily send limit?
The HubSpot send limit covers one-to-one emails sent from a connected inbox, including team inboxes connected to Conversations. The Sequences daily send limit is specific to automated sequence emails, including queued sends from paused or resumed enrollments. Both run on a rolling 24-hour window.
Can I set my own send limit in HubSpot?
Yes, on Sales Hub Professional or Enterprise. A custom daily send limit - set per day or per minute - overrides both the provider limit and the subscription's default sequences limit, and it applies per connected personal inbox.
How long does warming up a new domain take?
Most B2B domains need 3–4 weeks to reach a stable daily volume. HubSpot has no native warm-up feature, so this has to be managed manually through the custom send limit.
What should I do if bounce rate has already gone up?
Pause new enrollments, run the existing list through an email verification tool, and lower the mailbox's custom send limit for 2–3 weeks until the metrics stabilize.
Should cold outreach run on a separate domain?
Many teams send cold outreach from a subdomain (for example, outreach.company.com) rather than the primary company domain, so reputation risk from cold sending doesn't carry over to transactional and marketing email.