How to Warm Up 1,000 Email Accounts Safely

Warming up 1,000 email accounts in BobWork costs $1,980/month for a new account: 10 mailboxes are free and 990 are paid. If you skip ramping, DNS checks, and spam-rate monitoring, you can damage domains before outreach starts. This guide covers cost, CSV import, ramp math, pool choice, domain spread, and daily fleet checks.

BobWork Email Warm-up is free for the first 10 mailboxes, then bills only active mailboxes above that limit. Fleet accounts use the same engine described in the exact warm-up strategy: 3 emails per day at first, plus 2 per day, capped at 30 unless you edit the mailbox cap. If you are still comparing fleet sizes, start with the 50+ mailbox breakdown in the bulk warm-up cost guide.

What does 1,000 cost?

For a new account, 1,000 active mailboxes cost $1,980/month.

The first 10 mailboxes are free. Each active mailbox above 10 is billed by Stripe. Billing is prorated, extras pause without billing, and you can cancel any time.

Early users who created accounts before 27 October 2026 keep 20 free mailboxes for as long as they use the product. At large fleet sizes, that makes the same account $20/month cheaper. New accounts get 10 free mailboxes.

The default account limit is 200 mailboxes. For 500, 1,000, or larger fleets, request a higher limit at info@bobwork.ai before you import. Do this before buying domains or creating app passwords, because capacity mistakes create rework.

The price per mailbox falls to $2 from 60 mailboxes. That is why a 500-mailbox account costs $980/month and a 1,000-mailbox account costs $1,980/month.

How do you warm up 1000 email accounts?

Start by raising the account limit, then connect mailboxes by CSV. Do not add 1,000 mailboxes through single-mailbox forms. Bulk import gives each row the same IMAP and SMTP login test as a normal connection.

In the dashboard, go to Add mailbox → Many mailboxes: upload a CSV. Paste rows or upload a file with these columns.

CSV import is safe to repeat. If 40 rows fail because passwords are wrong, fix those rows and upload again. Already-connected mailboxes are skipped. Failed rows show the reason, so you can separate bad credentials from missing host settings.

For Gmail and Google Workspace fleets, use IMAP with an app password. Google app passwords require 2-Step Verification. Google documents the process in its official app-password help. Standardise this before generating hundreds of credentials.

BobWork also has one-click Google sign-in, but it is not the best bulk route today. Google caps unverified apps at 100 users, BobWork has not done the CASA audit, and Google shows an unverified-app notice. A Workspace admin can mark the app as trusted, but app passwords are cleaner for fleet onboarding.

Yahoo Mail and iCloud Mail also use app passwords. Lark Mail uses IMAP with a mail-client password. Zoho Mail can connect through the Zoho Mail API with a Self Client code, including on the Zoho free plan, or by IMAP on Mail Lite and above.

Amazon SES, SendGrid, and Mailgun use the platform SMTP credentials for sending plus a receiving inbox over IMAP. If you need provider-specific steps, use Google Workspace warm-up, Zoho Mail warm-up, SendGrid warm-up, or Mailgun warm-up.

What volume happens by day?

Each mailbox ramps on its own schedule. The default ramp starts at 3 warm-up emails per day, adds 2 per day, and caps at 30 per day. The cap is editable per mailbox, up to 100, but large fleets should not raise caps until spam-rate data is stable.

If all 1,000 mailboxes start on the same weekday, the fleet sends up to the numbers below. Weekends run at 30% of the normal level. Sends are spread across 09:00–18:00 in each mailbox's own time zone, with randomised decisions every 15 minutes.

These are warm-up emails, not cold emails. Warm-up builds normal mailbox activity. Outreach adds real prospect risk: complaints, bounces, unsubscribes, and poor lead quality.

BobWork replies to about 40% of received warm-up mail. Threads end after 3 messages. Warm-up content is plain text office talk, with no links and no images. The engine writes the messages, so users cannot push promotional copy through the network.

Set mailbox time zones before launch. If all mailboxes use one time zone, traffic compresses into one workday window. If your senders operate across regions, the local 09:00–18:00 pattern should match each mailbox.

Do not start cold outreach on day 1. For an existing domain, use at least 7 days of warm-up before outreach. For a new domain, use 2–3 weeks. The longer timeline is covered in the 21-day new-domain warm-up plan.

Should you use a private pool?

BobWork runs a shared warm-up network by default. Every active mailbox on the service exchanges warm-up mail with other active mailboxes across accounts. One mailbox is enough to start because it can warm with the shared network.

At 1,000 mailboxes, use a private pool unless you have a specific reason not to. BobWork recommends a private pool once you have 50+ mailboxes. In private mode, only your account's mailboxes warm each other, and nobody outside the account receives your addresses through warm-up.

Switch it in Mailbox pool → Pool mode. Private mode needs at least two mailboxes. A 1,000-mailbox fleet has enough internal variety to run without outside peers.

The shared network still fits small accounts, first tests, and teams with only one mailbox. It gives a new mailbox peers immediately. For an agency, lead-gen team, or multi-client fleet, private mode gives cleaner control and simpler separation.

The engine protects real mail in both modes. Only messages carrying the engine's hidden header are touched. For Zoho API senders, known warm-up subjects are used. Real mail is never read, moved, or answered.

Warm-up mail found in Spam is moved to Inbox, marked read, labelled Warm-up, and archived after 24 hours. This rescue action applies only to engine mail, so your team does not need to open 1,000 inboxes and drag messages by hand.

For a deeper comparison, read private warm-up pools versus public networks.

How should domains be spread?

Do not put 1,000 cold-email mailboxes on one domain. For outreach, a typical pattern is 2–5 mailboxes per domain. A 1,000-mailbox operation usually needs many domains, not one large sender domain.

Mailbox warm-up and domain warm-up are related, but not identical. Mailbox behaviour belongs to each inbox. Domain reputation belongs to the domain used in the From address and authentication records. The distinction is explained in domain warm-up versus mailbox warm-up.

Every domain needs SPF, DKIM, and DMARC. BobWork checks SPF, DKIM, and DMARC daily via DNS and shows the result per domain. DKIM selector detection includes common selectors such as google, zmail, default, selector1, selector2, k1, s1, mail, dkim, lark, feishu, and zoho.

Google's sender guidance says to keep spam rates reported in Postmaster Tools below 0.10% and avoid ever reaching 0.30%. Use the current Google email sender guidelines as the primary source. Yahoo's sender guidance also requires SPF, DKIM, DMARC, alignment, one-click unsubscribe for bulk mail, and spam rate below 0.3%; see Yahoo sender best practices.

For cold email, keep real outreach conservative. BobWork's published practice is no more than 30–50 real outreach emails per mailbox per day. During campaigns, keep warm-up at 10–15 per day. Add mailboxes rather than forcing more volume through each sender.

If a mailbox rises above 5% warm-up spam rate, pause it for a few days. Do not hide a bad sender inside a fleet average. One damaged domain can still hurt a client campaign.

What should you monitor daily?

Fleet monitoring needs two views: individual mailbox health and aggregate account trend. Averages show direction. Individual checks stop bad senders before they affect campaigns.

BobWork measures spam landings directly in receiving mailboxes. It does not use third-party seed lists. Spam rate means the share of a sender's warm-up mail that receiving mailboxes found in Spam over the last 7 days.

The health score runs from 0 to 100. Healthy is 85 or higher. Watch is 60–84. At risk is below 60. Blocked means the login or permission failed. Treat Blocked as an operations issue, not a deliverability signal.

Ready for outbound requires three conditions: 7+ days warming, 7-day spam rate of 3% or lower, and at least 30 warm-up emails received. If a mailbox misses one condition, keep it warming and exclude it from outreach.

Do not let campaign pressure override the ready gate. If 800 of 1,000 mailboxes are ready, send from 800. Keep the other 200 warming. Fleet systems fail when teams treat every mailbox as interchangeable.

Segment monitoring by domain, provider, and client. A Gmail-heavy domain group can behave differently from a Zoho group. A new domain can lag behind an established domain. A client with bad lead lists can damage otherwise healthy mailboxes once outreach begins.

When you start sending cold email, keep warm-up running on the same mailboxes. BobWork's Outbound feature only sends from mailboxes that pass the ready gate, but you can also use warm-up with another campaign tool. For sending limits, use how many cold emails per day is safe.

Do this now

Use this checklist before you import the fleet. It is easier to fix DNS, credentials, and pool mode before 1,000 mailboxes start generating activity.

Once the fleet is stable, lock the operating rules. Keep warm-up active. Keep real outreach to 30–50 emails per mailbox per day. Keep campaign warm-up at 10–15 per day. Add mailboxes for more volume instead of raising pressure on a small sender group.

BobWork Email Warm-up fits this use case when you need bulk CSV onboarding, a shared warm-up network by default, and a private pool per account for large fleets. Create the account, request the 1,000-mailbox limit, import the CSV, and use the dashboard readiness gate before outreach starts.

Frequently asked questions