Mailbox Limits Per Plan

Overview

WarmySender is a 4-pillar outreach platform — Cold Emailing, Email Warmup, LinkedIn Outreach, and Multichannel sequences. This page covers the account-wide mailbox cap that applies to every paid plan. The cap counts all email mailboxes — Gmail, Google Workspace, Outlook, Microsoft 365, Yahoo, Zoho, Hostinger, iCloud, Fastmail, ProtonMail, custom IMAP, and similar — whether connected by OAuth (Sign in with Microsoft) or app password over IMAP/SMTP. LinkedIn accounts are a separate add-on with their own limits.

The headline: every plan includes a generous mailbox cap and unlimited email warmup. Warmup volume is set by per-mailbox health and ramp mode (40-60/day), not by your plan tier — so warmup is truly unlimited from a billing standpoint regardless of how many mailboxes you attach.

Mailbox caps by plan

The cap applies account-wide — one pool shared across all your workspaces. Every paid plan also includes unlimited warmup across every connected mailbox, regardless of count.

For current pricing always defer to the pricing page — it is authoritative. The numbers above reflect the cap structure as of the May 9, 2026 rollout.

Account-wide, shared across workspaces

The cap applies to your account as a whole — all your workspaces draw from one shared pool. Workspaces remain the unit of deliverability isolation (each has its own warmup peer pool, sending domains, campaigns, and prospects), but the mailbox allotment is a single account-wide number you can split across them however you like.

Totals by plan (see also our Teams & Workspaces guide):

• Pro: up to 50 mailboxes total (1 workspace)
• Enterprise: up to 400 mailboxes total, shared across up to 5 workspaces
• Ultimate: up to 800 mailboxes total, shared across up to 10 workspaces

Concrete examples

Solo founder on Pro

One workspace, 50 mailboxes maximum. Warmup runs across every connected mailbox at full ramp (typically 40-60 emails/day each, depending on health score and ramp mode). For most solo cold-email use cases, 50 mailboxes is well above the volume needed to hit a 10,000-email/month send quota with conservative per-mailbox limits.

What happens when I try to connect a 51st mailbox on Pro?

You see an upgrade modal showing your current plan (Pro, 50 mailboxes) and the next plan up (Enterprise, 400 mailboxes for $69.99/month). The 51st connection is blocked at the connect screen — but your existing 50 mailboxes keep sending, warming up, and running sequences without interruption. Only NEW connections are blocked. Click Upgrade in the modal to expand your cap immediately, or remove a mailbox you no longer use to free a slot.

Trial behavior

If you are trialing Pro, you get Pro's 50-mailbox cap during the trial. Upgrading to Enterprise at any time during the trial expands your cap to 400 immediately — no waiting for the trial to end, no re-connecting mailboxes. Downgrading later follows the standard downgrade rules below (existing mailboxes keep working; only new attachments are blocked until you are back under the new cap).

Agency on Enterprise

Three workspaces (one per client) sharing the Enterprise account-wide pool of 400 mailboxes under a single $69.99/month subscription — split them however your clients need (say 150/150/100). Each client workspace stays fully isolated for deliverability: its own mailboxes, its own warmup peer pool, its own campaigns and prospects.

Large agency on Ultimate

Up to ten workspaces sharing the Ultimate account-wide pool of 800 mailboxes. Suitable for agencies running large outbound operations across multiple clients or business units.

Upgrade paths and price deltas

Each tier-up step multiplies the mailbox cap for a modest monthly delta:

• Pro → Enterprise: 50 → 400 mailboxes for +$55/month ($14.99 → $69.99). 8× the cap plus higher email send quota and multiple workspaces.
• Enterprise → Ultimate: 400 → 800 mailboxes for +$129.01/month ($69.99 → $199). 2× the cap plus highest email quota and team-member allowance.

Annual billing reduces every tier by ~40% (see the pricing page for current annual rates). For custom caps beyond Ultimate, contact [email protected].

What counts toward the cap

Every mailbox row attached to your workspace counts toward the cap, regardless of its current connection status:

• Connected — actively sending and receiving. Counts.
• Paused — temporarily disabled by you (e.g. paused for vacation). Counts.
• Disconnected — auth failure, password change, OAuth token expired. Counts (the row still exists; reconnect it or delete it to free the slot).
• Hard-deleted — removed from the workspace via the Delete button on the Mailboxes page. Does not count (frees a slot).

Why we count disconnected mailboxes: this matches existing legacy-tier behaviour and avoids two different counting rules in the platform. If you want to free a slot, either reconnect the mailbox (it returns to active) or delete it from the Mailboxes page. Soft-pausing a mailbox does not free its slot.

What happens when I downgrade

Your existing mailboxes keep working. We never auto-disable, auto-disconnect, or auto-delete mailboxes when you downgrade.

What changes: new attachments are blocked until your mailbox count is at or below your new plan's cap. For example, if you downgrade from Enterprise (400 cap) to Pro (50 cap) with 200 mailboxes attached, all 200 keep sending and warming up — but you cannot add a 201st until you either upgrade again or delete enough mailboxes to drop below 50.

The Mailboxes page shows an "over cap" banner with a clear next step: upgrade your plan or remove mailboxes you no longer need. Active warmup, sequences, and sending continue uninterrupted on every existing mailbox throughout. No data loss, no auto-disabled accounts, no broken campaigns.

Grandfathering policy

If you connected mailboxes before the May 2026 caps existed and your count exceeds the new cap, you keep all your mailboxes. We never auto-disconnect, auto-disable, or auto-delete. You can only add new ones once you're back under the cap, OR by upgrading to a tier whose cap covers your current count.

Example: a customer on Pro with 80 mailboxes connected pre-rollout keeps all 80 sending and warming up. They cannot add an 81st until either (a) they delete enough mailboxes to drop below 50, or (b) they upgrade to Enterprise (which raises their cap to 400, making all 80 fully under-cap with 320 slots to spare).

Cancelling and re-subscribing does not preserve grandfathered status. A fresh subscription starts under the current cap structure.

Deleted mailboxes free a slot immediately

When you click Delete on a mailbox, the slot is freed immediately. You can add a replacement mailbox right away, even on the same email address. Sending and warmup stop for the deleted mailbox at the moment you confirm — paused, disconnected, and auth-failing mailboxes still count toward your cap (because they are still attached), but a deleted mailbox does not.

LinkedIn accounts are billed separately

LinkedIn accounts do NOT count toward the mailbox cap. They are billed separately on a per-seat basis ($15/seat/month per workspace, 1-10 seats). A Pro customer can have 50 email mailboxes AND 3 LinkedIn seats simultaneously without either capacity affecting the other. For LinkedIn limits and seat billing, see LinkedIn campaign documentation.

Frequently asked questions

Can I have multiple workspaces with their own caps?

Yes. Enterprise and Ultimate include multiple workspaces (5 and 10 respectively), and every workspace gets its own full mailbox cap. Create additional workspaces from the workspace switcher in the sidebar — there is no extra charge beyond your subscription.

Do disconnected mailboxes count toward my cap?

Yes. Any attached mailbox counts, regardless of whether it is connected, paused, or disconnected. Only deletion frees a slot — soft-pausing or auth-failing does not. Deleting a mailbox from the Mailboxes page frees the slot immediately.

How do I add more mailboxes if I am at my cap?

Two options. Either upgrade your plan for a higher cap (Pro → Enterprise gets you 8× more mailboxes for $55/month extra), or delete mailboxes you no longer use from the Mailboxes page to free slots. The Add Mailbox button is enabled the moment you are below the cap.

Does warmup count toward the mailbox cap?

No. Warmup is included on every paid plan with no per-mailbox or per-volume fee. Every connected mailbox can run full warmup — typically 40-60 warmup emails per day each, depending on health score and ramp mode. The cap counts the number of attached mailboxes, not the warmup volume.

What happens if I bulk-import a CSV with more rows than my cap allows?

The import attaches rows up to your remaining cap, then stops. The response tells you exactly how many were imported and how many were skipped. For example, a Pro user with 30 mailboxes already attached who imports 100 rows will see 20 attached and 80 skipped, with an upgrade link in the response.

Does this cap apply to LinkedIn accounts?

No. The mailbox cap covers SMTP, IMAP, and OAuth email mailboxes only. LinkedIn accounts are a separate add-on with their own per-seat billing ($15/seat/month per workspace). For LinkedIn limits, see LinkedIn campaign documentation.

Can I get more than 800 mailboxes on Ultimate?

Yes — we support custom limits for high-volume agencies and enterprise customers. Contact us at [email protected] with a brief description of your use case and we will set up a custom plan.

Next steps

• Upgrade your plan for a higher mailbox cap.
• Compare plans on the pricing page to see all included features by tier.
• Contact us for custom limits or enterprise plans.

Related documentation

• Comparing Plans: Pro vs Enterprise vs Ultimate — full feature matrix.
• Billing & Subscription Plans — how billing works across workspaces and the LinkedIn add-on.
• Teams & Workspaces — how workspace isolation works.
• Connecting Your Mailbox — IMAP/SMTP and OAuth setup.
• Bulk Mailbox Import — CSV format and tier limits.