InboxKit alternatives: warmup and sending in the price, $147 a month less at 100 mailboxes

InboxKit charges $3 per Google or Microsoft mailbox on monthly billing, $2.50 only on annual billing, and $3 more per mailbox for warmup. It has no sequencer. Outreach2day charges $2.50 on monthly billing with warmup and a sequencer included: $250 at 100 mailboxes against $397 for InboxKit plus an Instantly plan. We make Outreach2day and rank it first.

Create mailboxesBook a call
  • Warmup and sending included
  • $2.50 a mailbox, 12 minimum
  • Month-to-month billing

Full setup · 100 mailboxes · 55,000 emails a month

$147less a month with Outreach2day, $1,764 a year

Outreach2day$250 / mo
InboxKit + Instantly$397 / mo

Mailboxes, warmup and a sequencer at list prices, monthly billing. Line items in the cost table below.

teams have used Outreach2day
3,600+
emails sent a day
40M+

Among them

  • SalesSourcers
  • Vivid
  • OptiQ.AI
  • SLSBMB
  • Outreacher
  • Outpush

Why Outreach2day tops this list

  • $2.50 on monthly billing

    InboxKit reaches $2.50 per mailbox only on annual billing, paid in advance and generally non-refundable. Our $2.50 is the month-to-month price.

  • Warmup inside the $2.50

    InboxKit's warmup costs $3 per mailbox a month, as much as the mailbox. At 100 mailboxes that is $300 a month. Ours runs on every mailbox inside the $2.50.

  • A sender in the same bill

    InboxKit exports to 24+ sequencers, and you pay one of them. Campaigns, sequences and a reply inbox are part of our subscription.

InboxKit sells Google Workspace, Microsoft 365 and Azure mailboxes with no minimum. Ours are SMTP/IMAP from 12 mailboxes.

7 InboxKit alternatives, ranked

Options outside the cost table below show their full setup at 100 mailboxes here.

  1. 1. Outreach2day: warmup and a sequencer included, monthly billing

    The mailbox, its warmup (25+ warmup emails a day to Google recipients, 25 to Outlook, 25 to other providers) and the sequencer are one $2.50 line. Leaving InboxKit for us removes two bills: the $3 warmup add-on and the sequencer. Mailboxes are SMTP/IMAP on your domains (no Google or Microsoft seats), and they sync to Instantly or Smartlead if you keep one. source

    Warmup includedSending included

  2. 2. Zapmail: Google and Microsoft mailboxes with warmup handled

    The closest swap if you need Google Workspace or Microsoft 365: Zapmail sells both at the same prices in plans of 10, 30 and 100, and its FAQ says it handles warmup. There is no sequencer, and Zapmail gives no refunds. source (opens the vendor's page in a new tab)

    Warmup includedSending not included

  3. 3. Premium Inboxes: done-for-you Google and Microsoft inboxes

    Premium Inboxes builds the inboxes, checks DNS by hand and uploads them to your sequencer, with free replacements. Per inbox it costs more than InboxKit ($3.50 under 250 inboxes), and warmup runs in your sequencer. source (opens the vendor's page in a new tab)

    Warmup extra or partialSending not included

  4. 4. Mailforge: SMTP slots inside the Forge products

    If you are moving off Google and Microsoft to cut cost, Mailforge sells shared-IP SMTP slots from $3 a month. Warmup is Warmforge and sending is Salesforge, each a separate subscription. source (opens the vendor's page in a new tab)

    Warmup extra or partialSending not includedFull setup at 100 mailboxes: $397 / mo

  5. 5. Maildoso: SMTP mailboxes at $2.50 for teams with a sequencer

    Maildoso's mailbox price matches InboxKit's annual price on monthly billing, but each mailbox sends up to 15 cold emails a day, warmup comes from another tool, and the plan starts at 30 mailboxes. source (opens the vendor's page in a new tab)

    Warmup not includedSending not includedFull setup at 100 mailboxes: $514.50 / mo

  6. 6. Instantly: Google accounts bought inside the sequencer

    Instantly sells done-for-you Google accounts at $5 a month on top of its plan, with warmup in the plan. The accounts work only inside Instantly, and Instantly keeps the domains. source (opens the vendor's page in a new tab)

    Warmup includedSending extra or partial

  7. 7. Smartlead: Google, Outlook and SMTP mailboxes inside Smartlead

    SmartSenders are Google and Outlook mailboxes at $4.50, resold from Zapmail and InfraInbox, plus SMTP from $3.99. They stay inside Smartlead, and the Smartlead plan is extra. source (opens the vendor's page in a new tab)

    Warmup includedSending extra or partialFull setup at 100 mailboxes: $544 / mo

InboxKit and more options side by side

Vendors that sell Google and Microsoft mailboxes like InboxKit, plus ours: lowest published per-mailbox price, smallest order, warmup, API and MCP, from their own pages in October 2026.

Outreach2day fits if

  • You run 1,000+ mailboxes: we quote a volume price below every vendor list price in our comparisons, warmup and sending included
  • You pay InboxKit's $3 warmup add-on and want warmup inside the mailbox price
  • You want $2.50 on monthly billing instead of committing a year
  • You want an MCP server for an AI assistant

Outreach2day does not fit if

  • Your clients require Google Workspace or Microsoft 365 accounts
  • You need 1 to 11 mailboxes
  • You want Azure-tenant Microsoft mailboxes at $30 for up to 100

InboxKit: pricing, limits and who it fits

From InboxKit's own pages, read .

Pricing model
A flat price per mailbox, the same for Google Workspace and Microsoft 365: $3.00 a month on monthly billing, $2.70 quarterly, $2.50 on annual billing. Sold per mailbox, with no minimum.source (opens the vendor's page in a new tab)
Azure
Azure tenants are priced per tenant: $30 a month for up to 100 mailboxes.source (opens the vendor's page in a new tab)
Warmup
An add-on at $3 per mailbox a month: a 14-day isolated warmup, then low ongoing volume alongside outreach.source (opens the vendor's page in a new tab)
Monitoring
InfraGuard, an add-on with the first month free: blacklist, DNS, bounce-rate and inbox-placement checks every six hours, with alerts and auto-pause.source (opens the vendor's page in a new tab)
Sending
No sequencer. One-click export to 24+ sequencers, including Instantly, Smartlead, lemlist and Apollo; API with webhooks on every plan.source (opens the vendor's page in a new tab)
Refunds
Subscriptions are billed in advance and generally non-refundable, with no pro-rata refunds; domains are non-refundable once registered.source (opens the vendor's page in a new tab)

What InboxKit is good at

Pick InboxKit if

  • You want Google Workspace or Microsoft 365 mailboxes one at a time, without a plan or a minimum.
  • You already send from a sequencer with warmup and can commit to annual billing for the $2.50 price.

What the full setup costs each month

Mailboxes, warmup and a sequencer at the same email volume, every line item listed. Set your volume.

Outreach2day, mailboxes/ moWarmup, sending, the inbox and analytics included.
Create 100 mailboxes

The same volume elsewhere

  • Outreach2day
    Mailboxes with warmup and a sequencer included
  • InboxKit more
    $3.00 per mailbox a month on monthly billing; warmup from the Instantly plan instead of the $3 add-on; sequencer with warmup: Instantly Growth $47 (5,000 emails), Hypergrowth $97 (125,000 emails), Hypergrowth + add-on $184 (250,000 emails), Light Speed $358 (500,000 emails) a month

  • Outreach2dayMailboxes + warmup + sequencer

    25 mailboxes
    $62.50 / mo25 mailboxes × $2.50, warmup and a sequencer included $62.50
    100 mailboxes
    $250 / mo100 mailboxes × $2.50, warmup and a sequencer included $250
    400 mailboxes
    $1,000 / mo400 mailboxes × $2.50, warmup and a sequencer included $1,000

  • ZapmailMailboxes

    25 mailboxes
    $188.50 / moZapmail Starter + 15 extra mailboxes $91.50 + Instantly Hypergrowth $97
    100 mailboxes
    $396 / moZapmail Pro (100 mailboxes) $299 + Instantly Hypergrowth $97
    400 mailboxes
    $1,383 / moZapmail Pro + 300 extra mailboxes $1,199 + Instantly Hypergrowth + add-on $184

  • Premium InboxesMailboxes

    25 mailboxes
    $184.50 / mo25 inboxes × $3.50 $87.50 + Instantly Hypergrowth $97
    100 mailboxes
    $447 / mo100 inboxes × $3.50 $350 + Instantly Hypergrowth $97
    400 mailboxes
    $1,384 / mo400 inboxes × $3.00 $1,200 + Instantly Hypergrowth + add-on $184

  • InstantlySequencer + mailboxes

    25 mailboxes
    $222 / mo25 Google accounts × $5 $125 + Instantly Hypergrowth $97
    100 mailboxes
    $597 / mo100 Google accounts × $5 $500 + Instantly Hypergrowth $97
    400 mailboxes
    $2,184 / mo400 Google accounts × $5 $2,000 + Instantly Hypergrowth + add-on $184

  • InboxKitMailboxes

    25 mailboxes
    $172 / mo25 mailboxes × $3.00 $75 + Instantly Hypergrowth $97
    100 mailboxes
    $397 / mo100 mailboxes × $3.00 $300 + Instantly Hypergrowth $97
    400 mailboxes
    $1,384 / mo400 mailboxes × $3.00 $1,200 + Instantly Hypergrowth + add-on $184

How we count: 550 cold emails per mailbox a month (25 a day on 22 working days), the same for every vendor. List prices on monthly billing, in USD, excluding domains, taxes and discounts. A vendor that does not sell sending gets the cheapest Instantly plan that covers the volume.

Included in the $2.50

Everything a cold email setup needs, in one mailbox price

One subscription at $2.50 a mailbox, from 12 mailboxes ($30 a month), everything included

  • Sequencer included

    Warmup and a sequencer

    • Warmup for the life of every mailbox
    • Campaigns, sequences, schedules and follow-ups
    • One inbox for replies from all mailboxes
  • Per mailbox

    Analytics that show which mailboxes still land

    • Warmup inbox, spam and bounce rate for every mailbox
    • Sends by recipient provider
    • Google and Outlook placement tests
  • Deliverability

    SSL domain masking and link protection

    SSL domain masking on sending domains and automatic link replacement in emails; SPF, DKIM, DMARC and redirect to your site set up automatically

  • REST API

    An API on every account

    Script domains, DNS and warmup, or pull mailbox data into your own tools

    curl · public.outreach2day.com
    # OUTREACH2DAY_API_KEY: a key from app → API keyscurl "https://public.outreach2day.com/warmup/mailboxes?workspaceId=123" \  -H "Authorization: Bearer $OUTREACH2DAY_API_KEY"
  • MCP server

    Run it from Claude, Cursor or Codex

    Your AI assistant checks domains, quotes mailboxes and sets up DNS, warmup and campaigns. Add the server URL to Claude, ChatGPT, Cursor or Codex and sign in with your Outreach2day account; turn on Prepare orders at sign-in, then approve and pay on Stripe

    Server URL
    https://public.outreach2day.com/mcp
    Or install for every client · macOS / Linux
    curl -fsSL https://outreach2day.com/install | sh
    Setup for each client
  • 14 tools

    Keep the sequencer you already use

    Instantly and Smartlead sync by API key; 12 more get a CSV in their own import format. Setup per tool

    • Instantly
    • Smartlead
    • SalesHandy
    • Reply.io
    • Apollo
    • Snov.io
    • Mailshake
    • ReachInbox
    • PlusVibe
    • Luna
    • Nureply
    • Coldy
    • MailToaster
    • EmailBison
  • Hundreds of mailboxes

    Enterprise support

    A shared Slack channel and a dedicated account team, for companies running hundreds or thousands of mailboxes

    Talk to us

The details

Check which InboxKit costs you would actually replace

Start with your current invoice and the mailbox host your client requires. A Google Workspace address and an SMTP address can both send a campaign, but changing hosts also changes the account you sign in to. If Google or Microsoft seats are a contract requirement, keep those providers in the shortlist before comparing the monthly total.

Next, check where warmup runs today. A team already using the warmup in its sequencer should compare InboxKit's mailbox-only line, rather than adding the $3 warmup charge twice. A team paying InboxKit for warmup needs to include that add-on in the outgoing bill. Finally, check the renewal date before ordering replacements: prepaid annual service and a fresh monthly order can overlap while the new accounts warm up.

What InboxKit costs with warmup and a sender

The plans, warmup add-on and billing terms are in InboxKit pricing 2026.

InboxKit's mailbox price depends on the billing term: $3.00 a month on monthly billing, $2.70 quarterly, $2.50 annual. Warmup is $3 per mailbox a month. InfraGuard monitoring is an add-on with the first month free. Subscriptions are billed in advance and generally non-refundable.

With the warmup in an Instantly plan instead of InboxKit's add-on: $172 at 25 mailboxes, $397 at 100, $1,384 at 400. With InboxKit's own warmup the mailbox line doubles: $600 a month at 100 mailboxes before a sequencer. Ours: $62.50, $250 and $1,000, all in.

Google and Microsoft mailboxes or SMTP

InboxKit sells real Google Workspace and Microsoft 365 accounts. If your client or your team requires those, the alternatives are Zapmail, Premium Inboxes, Instantly's Google accounts or SmartSenders.

If the requirement is inbox placement and not the account type, test before you decide. Mail from the same mailbox can land in the inbox at Outlook and in spam at Gmail, whoever hosts it. Our mailboxes come with Google and Outlook placement tests, so you can compare them against your InboxKit mailboxes on the same copy.

Pick by the reason you are leaving InboxKit

The bill is too high: most of it is usually the warmup add-on and the sequencer. Outreach2day removes both; Maildoso and Mailforge lower the mailbox line but keep the sequencer.

You don't want to prepay a year for $2.50: our $2.50 is billed month to month, and Maildoso's $2.50 is its monthly plan price from 30 mailboxes.

You need Google or Microsoft but want warmup handled: Zapmail. You want someone else to build and replace the inboxes: Premium Inboxes.

You want mailboxes and sending from one vendor and don't mind the lock-in: Instantly or Smartlead, whose own mailboxes stay inside their tools.

Customers

What customers say

  • “That was the best infrastructure and value for money I saw.”
    Ido RebhunIdo RebhunRenaissance
  • “…deliverability with your inboxes is better than our outlook/google inboxes…”
    Daniel DultsinDaniel DultsinControl
  • “We really would like to thank you for that report. We don’t know what we are doing with email and it is very reassuring to us to know we have a partner on top of the ball.”
    ReilcapBill OConnorReilcap

Switching from InboxKit

  1. Create mailboxes in Outreach2day on new domains. SPF, DKIM and DMARC are set automatically.
  2. Warmup starts on its own. Send no cold email from them for 14 days.
  3. Keep your InboxKit mailboxes sending while ours ramp; ours reach up to 25 cold emails a day around day 21.
  4. Send from our own sequencer, or sync the new mailboxes to the sequencer you export InboxKit mailboxes to today.
  5. Cancel InboxKit at the end of its billing period. On annual billing, plan the switch for the renewal date: InboxKit gives no pro-rata refunds.

InboxKit alternatives: questions

What is the cheapest InboxKit alternative?

For the full setup at 100 mailboxes, Outreach2day at $250 a month, with warmup and a sequencer included. InboxKit plus an Instantly plan costs $397.

Does InboxKit include warmup?

No. Warmup is an add-on at $3 per mailbox a month: 14 days of isolated warmup, then low ongoing volume. Outreach2day includes warmup in the $2.50 mailbox.

Which InboxKit alternatives sell Google Workspace mailboxes?

Zapmail, Premium Inboxes and Instantly. Smartlead resells Google and Outlook mailboxes as SmartSenders. Outreach2day, Maildoso and Mailforge sell SMTP mailboxes.

Is InboxKit's $2.50 the same as Outreach2day's $2.50?

No. InboxKit's $2.50 is the annual-billing price of the mailbox alone. Ours is the monthly price and includes warmup and the sequencer.

What does InboxKit's InfraGuard add-on check?

Blacklists, DNS records, bounce rate and inbox placement every six hours, with alerts and auto-pause; the first month is free. Our per-mailbox warmup inbox, spam and bounce rates and the Google and Outlook placement tests come with the mailbox.

Does InboxKit have a minimum order?

No, you can buy one mailbox. Our minimum is 12 mailboxes, $30 a month.

Deliverability call

Talk to our deliverability team

Book a call with the people who run our mailbox infrastructure. We look at your current setup and tell you what to change. Running 1,000+ mailboxes? We also quote a volume price below every vendor list price in our comparisons, warmup and sending included.

  • Review your domains, DNS records and current inbox placement
  • Size the setup: domains, mailboxes per domain and daily volume per mailbox
  • Plan warmup and the move from your current provider or sequencer
  • 1,000+ mailboxes: a volume price per mailbox for your setup

Free call

See open times in your time zone and book on this page.

Or open the booking page

More comparisons and guides

Sources

Checked . Vendors change prices and plans; if something here is out of date, write to support@outreach2day.com and we will fix it.

First cold emails on day 14, full volume on day 21

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