8 providers scoredPrices checked

Cold email infrastructure providers, compared and scored

Eight providers, seven published criteria, every fact linked to the vendor's own page. Priced as a full setup: mailboxes, warm-up and a sending engine at 25, 100 and 400 mailboxes.

Create mailboxesBook a call
  • Warm-up and sending included
  • $2.50 a mailbox, 12 minimum
  • No contract

Top 5 of 8 · weighted score

  1. 1. Outreach2day9.1 / 10
  2. 2. Smartlead7.3 / 10
  3. 3. Zapmail7.1 / 10
  4. 4. Mailforge6.9 / 10
  5. 5. Instantly6.9 / 10

We are one of the vendors. The rules and every source are on this page.

Scores

The scores

Out of 10, weighted. Open a vendor for each score and its source. Prices checked Sep 28, 2026.

  1. 1. Outreach2dayMailboxes + warm-up + sending9.1 / 10
  2. 2. SmartleadSequencer + mailboxes7.3 / 10
  3. 3. ZapmailMailboxes7.1 / 10
  4. 4. MailforgeMailboxes6.9 / 10
  5. 5. InstantlySequencer + mailboxes6.9 / 10
  6. 6. InboxKitMailboxes6.6 / 10
  7. 7. MaildosoMailboxes6.0 / 10
  8. 8. Premium InboxesMailboxes5.6 / 10

Method

How we score

Seven criteria, each scored 0 to 10 by the rule in the table. The total is the weighted average.

Cost weighs most because setups differ most there: the monthly cost of 100 mailboxes with warm-up and a sending engine, at list prices. A vendor that sells mailboxes only gets the cheapest Instantly plan for the volume, because you can't send without one.

We sell mailboxes, so we are in this table. The criteria favor a bundle like ours. We lose points for SMTP-only mailboxes and for no blacklist monitoring. If you already pay for a sequencer, read the mailbox price and mailbox type rows instead of the total.

We don't score deliverability. Placement depends on your list, copy and volume as much as on the vendor, and no one can test eight vendors on equal terms.

Scoring criteria, weights and rules
CriterionWeight
Full-stack costMonthly cost of 100 mailboxes, warm-up and a sending engine at list prices. The cheapest setup gets 10; the others get 10 × cheapest ÷ their cost.30%
Warm-up10: included in the mailbox or plan price. 5: sold as a paid add-on. 2: not offered; you bring your own warm-up tool.15%
Sending engine10: mailboxes and a sending engine in one subscription. 6: the same vendor sells both, as two separate purchases. 2: mailboxes only; you pay for a sequencer elsewhere.15%
Mailbox types10: Google Workspace, Microsoft 365 and SMTP mailboxes. 7: two of the three. 4: one type.10%
Setup10: domains bought in the app and SPF, DKIM and DMARC set automatically. 6: DNS set automatically, domains bought elsewhere. 3: manual DNS.10%
MonitoringOne third of 10 for each of: inbox placement tests, blacklist checks, per-mailbox health or sending stats. A separate plan or add-on still counts.10%
API and export5 for a public API, 5 for a documented way to move or connect the mailboxes to other sending tools.10%

Evidence

Every score and the fact behind it

Each line links to the vendor's public page we took the fact from.

Outreach2day9.1 / 10

Cold email mailboxes with warm-up, a sending engine and per-mailbox analytics in one $2.50 subscription.

Full-stack cost
10.0
$250 a month for 100 mailboxes with warm-up and sending (100 mailboxes × $2.50, warm-up and sending included). source
Warm-up
10.0
Warm-up is included in the mailbox price. source
Sending engine
10.0
The sending engine is part of the same $2.50 subscription. source
Mailbox types
4.0
One type: SMTP/IMAP mailboxes. No Google Workspace or Microsoft 365. source
Setup
10.0
Domains are bought in the app; SPF, DKIM and DMARC are set automatically. source
Monitoring
6.7
Per-mailbox warm-up inbox, spam and bounce rate, and Google and Outlook placement tests. No blacklist monitoring. source
API and export
10.0
REST API on every account; mailboxes sync to Instantly and Smartlead and export to 14 tools. source

Smartlead7.3 / 10

A cold email sending platform that resells Google, Outlook and SMTP mailboxes from partner providers as SmartSenders.

Full-stack cost
4.6
$544 a month for 100 mailboxes with warm-up and sending (100 mailboxes × $4.50 + Smartlead Pro). source (opens the vendor's page in a new tab)
Warm-up
10.0
Unlimited warm-up is included on every plan. source (opens the vendor's page in a new tab)
Sending engine
6.0
Smartlead sells both, as two purchases: a plan and SmartSenders mailboxes. source (opens the vendor's page in a new tab)
Mailbox types
10.0
Google, Outlook and SMTP mailboxes through SmartSenders. source (opens the vendor's page in a new tab)
Setup
10.0
Domains are bought in Smartlead; DNS, SPF and DKIM are handled. source (opens the vendor's page in a new tab)
Monitoring
10.0
Placement tests, blacklist checks and sender health trends (SmartDelivery, separate plan from $49 a month). source (opens the vendor's page in a new tab)
API and export
5.0
API on Pro and above. SmartSenders mailboxes can't be used outside Smartlead. source (opens the vendor's page in a new tab)

Zapmail7.1 / 10

Google Workspace and Microsoft 365 mailboxes with automated DNS, sold in plans of 10, 30 and 100. No sending engine.

Full-stack cost
6.3
$396 a month for 100 mailboxes with warm-up and sending (Zapmail Pro (100 mailboxes) + Instantly Hypergrowth). source (opens the vendor's page in a new tab)
Warm-up
10.0
Zapmail's FAQ says warm-up is handled for you. source (opens the vendor's page in a new tab)
Sending engine
2.0
Mailboxes only; they export to 50+ outreach tools. source (opens the vendor's page in a new tab)
Mailbox types
7.0
Google Workspace and Microsoft 365. source (opens the vendor's page in a new tab)
Setup
10.0
Domains are bought in Zapmail; SPF, DKIM and DMARC are set automatically. source (opens the vendor's page in a new tab)
Monitoring
6.7
Placement test credits on every plan, each with a blacklist check. We found no per-mailbox health stats on its pages. source (opens the vendor's page in a new tab)
API and export
10.0
API on the Pro plan; exports to 50+ tools. source (opens the vendor's page in a new tab)

Mailforge6.9 / 10

Shared-IP SMTP mailboxes billed per slot. Warm-up (Warmforge) and sending (Salesforge) are separate Forge products.

Full-stack cost
6.3
$397 a month for 100 mailboxes with warm-up and sending (Mailforge 100 slots + Instantly Hypergrowth). source (opens the vendor's page in a new tab)
Warm-up
5.0
Warm-up is Warmforge, a separate Forge product. source (opens the vendor's page in a new tab)
Sending engine
6.0
Sending is Salesforge, a separate Forge product. source (opens the vendor's page in a new tab)
Mailbox types
4.0
Mailforge sells SMTP; Google and Microsoft mailboxes are a separate product, Primeforge. source (opens the vendor's page in a new tab)
Setup
10.0
Domains are bought in Mailforge; SPF, DKIM and DMARC are set automatically. source (opens the vendor's page in a new tab)
Monitoring
10.0
Placement tests, blacklist checks and per-mailbox health, in Warmforge. source (opens the vendor's page in a new tab)
API and export
10.0
Public API; works with any sending tool. source (opens the vendor's page in a new tab)

Instantly6.9 / 10

A cold email sending platform that also sells done-for-you Google accounts, pre-warmed accounts and its own SMTP inboxes.

Full-stack cost
4.2
$597 a month for 100 mailboxes with warm-up and sending (100 Google accounts × $5 + Instantly Hypergrowth). source (opens the vendor's page in a new tab)
Warm-up
10.0
Warm-up is included on every Outreach plan. source (opens the vendor's page in a new tab)
Sending engine
6.0
Instantly sells both, as two purchases: an Outreach plan and accounts per month. source (opens the vendor's page in a new tab)
Mailbox types
7.0
Google accounts and AirMail SMTP inboxes; Microsoft only if you connect your own. source (opens the vendor's page in a new tab)
Setup
10.0
Domains are bought in Instantly; MX, SPF, DKIM and DMARC are set up for you. source (opens the vendor's page in a new tab)
Monitoring
10.0
Account analytics on every plan; placement tests and blacklist monitoring on a separate plan from $47 a month. source (opens the vendor's page in a new tab)
API and export
5.0
API on all plans. Done-for-you accounts can't be used outside Instantly. source (opens the vendor's page in a new tab)

InboxKit6.6 / 10

Google Workspace and Microsoft 365 mailboxes at a flat per-mailbox price, with warm-up as an add-on. No sending engine.

Full-stack cost
6.3
$397 a month for 100 mailboxes with warm-up and sending (100 mailboxes × $3.00 + Instantly Hypergrowth). source (opens the vendor's page in a new tab)
Warm-up
5.0
Warm-up is an add-on at $3 per mailbox a month. source (opens the vendor's page in a new tab)
Sending engine
2.0
Mailboxes only; 24+ integrations. source (opens the vendor's page in a new tab)
Mailbox types
7.0
Google Workspace and Microsoft 365. source (opens the vendor's page in a new tab)
Setup
10.0
Domains registered through InboxKit; SPF, DKIM and DMARC automated. source (opens the vendor's page in a new tab)
Monitoring
10.0
Per-mailbox analytics and alerts included; blacklist checks and placement tests in the InfraGuard add-on. source (opens the vendor's page in a new tab)
API and export
10.0
REST API with webhooks; 24+ integrations and app passwords. source (opens the vendor's page in a new tab)

Maildoso6.0 / 10

SMTP mailboxes on Maildoso's own servers and IPs, sold in plans of 30, 300 and 1,000. No warm-up and no sending engine.

Full-stack cost
7.8
$322 a month for 100 mailboxes with warm-up and sending (Maildoso 300-mailbox plan (smallest plan for the 167 needed at 15 a day) + Instantly Hypergrowth). source (opens the vendor's page in a new tab)
Warm-up
2.0
Not included: Maildoso tells you to use outside providers or the Instantly warm-up pool. source (opens the vendor's page in a new tab)
Sending engine
2.0
Mailboxes only; they sync to Instantly, Smartlead or EmailBison. source (opens the vendor's page in a new tab)
Mailbox types
4.0
One type: SMTP mailboxes on Maildoso's servers. source (opens the vendor's page in a new tab)
Setup
10.0
Domains are bought in Maildoso; SPF, DKIM and DMARC are set automatically. source (opens the vendor's page in a new tab)
Monitoring
6.7
Placement tests every 3 days and per-mailbox health scores. We found no blacklist monitoring on its pricing page. source (opens the vendor's page in a new tab)
API and export
10.0
REST API and MCP on every plan; sync to three sequencers and CSV export. source (opens the vendor's page in a new tab)

Premium Inboxes5.6 / 10

Google Workspace and Microsoft 365 inboxes, set up for you and uploaded to your sequencer. No sending engine.

Full-stack cost
5.6
$447 a month for 100 mailboxes with warm-up and sending (100 inboxes × $3.50 + Instantly Hypergrowth). source (opens the vendor's page in a new tab)
Warm-up
2.0
Warm-up runs in your own sequencer; Premium Inboxes switches it on during setup. source (opens the vendor's page in a new tab)
Sending engine
2.0
Inboxes only; they are uploaded to your sequencer. source (opens the vendor's page in a new tab)
Mailbox types
7.0
Google Workspace and Microsoft 365. source (opens the vendor's page in a new tab)
Setup
6.0
DNS and SPF/DKIM/DMARC are done for you; the page contradicts itself on whether it sells domains. source (opens the vendor's page in a new tab)
Monitoring
10.0
Dashboard and health checks; placement tests and blacklist monitoring in the $7,500-a-month Operations tier. source (opens the vendor's page in a new tab)
API and export
10.0
Client API on every plan; inboxes are uploaded to six sequencers. source (opens the vendor's page in a new tab)

Cost

What the full setup costs each month

Mailboxes, warm-up and a sending engine at 25, 100 and 400 mailboxes (550 cold emails per mailbox a month). Domains are not included.

  • Outreach2dayMailboxes + warm-up + sending

    25 mailboxes
    $62.50 / mo25 mailboxes × $2.50, warm-up and sending included $62.50
    100 mailboxes
    $250 / mo100 mailboxes × $2.50, warm-up and sending included $250
    400 mailboxes
    $1,000 / mo400 mailboxes × $2.50, warm-up and sending included $1,000

  • 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

  • SmartleadSequencer + mailboxes

    25 mailboxes
    $206.50 / mo25 mailboxes × $4.50 $112.50 + Smartlead Pro $94
    100 mailboxes
    $544 / mo100 mailboxes × $4.50 $450 + Smartlead Pro $94
    400 mailboxes
    $2,028 / mo400 mailboxes × $4.50 $1,800 + Smartlead 240K sends $228

  • MaildosoMailboxes

    25 mailboxes
    $322 / moMaildoso 300-mailbox plan (smallest plan for the 42 needed at 15 a day) $225 + Instantly Hypergrowth $97
    100 mailboxes
    $322 / moMaildoso 300-mailbox plan (smallest plan for the 167 needed at 15 a day) $225 + Instantly Hypergrowth $97
    400 mailboxes
    $683 / moMaildoso 1,000-mailbox plan (smallest plan for the 667 needed at 15 a day) $499 + Instantly Hypergrowth + add-on $184

  • 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

  • MailforgeMailboxes

    25 mailboxes
    $172 / moMailforge 25 slots $75 + Instantly Hypergrowth $97
    100 mailboxes
    $397 / moMailforge 100 slots $300 + Instantly Hypergrowth $97
    400 mailboxes
    $1,267 / moMailforge 400 slots $1,083 + 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

  • 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, without domains, taxes or discounts. A vendor that does not sell sending gets the cheapest Instantly plan that covers the volume.

Create mailboxesBook a call

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). No add-ons to buy.

  • No sequencer bill

    Warm-up and a sending engine

    • Warm-up 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

    • Warm-up 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 for your sending domains and automatic link replacement in your emails. SPF, DKIM, DMARC and a redirect to your site are set for you.

  • REST API

    An API on every account

    Script domains, DNS and warm-up, or pull mailbox data into your own tools.

    curl · public.outreach2day.com
    export O2D_KEY=ot2d_...   # app → API keyscurl "https://public.outreach2day.com/warmup/mailboxes?workspaceId=123" \  -H "Authorization: Bearer $O2D_KEY"
  • MCP server · early access

    Run it from Claude or any AI agent

    Manage domains, mailboxes and warm-up by asking Claude or any MCP client.

    Get early access
  • 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.

    • 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

Head to head

Side-by-side comparisons

FAQ

Questions

What is cold email infrastructure?

The mailboxes and domains you send cold email from, their DNS records (SPF, DKIM, DMARC), warm-up, and the tool that sends the sequences. Some vendors sell only mailboxes, some only the sending tool, some both.

Which cold email infrastructure provider is cheapest?

For the full setup at 100 mailboxes: Outreach2day, at $250 a month. At 400 mailboxes, Maildoso plus an Instantly plan costs $683 against our $1,000. For mailboxes alone at volume, Maildoso's 1,000-mailbox plan ($499) is the lowest per-mailbox price we found.

Do I need Google Workspace or Microsoft 365 mailboxes for cold email?

No. Plenty of teams send from SMTP/IMAP mailboxes, and ours are SMTP/IMAP. If you want Google or Microsoft, Zapmail, InboxKit and Premium Inboxes sell both, and Instantly sells Google accounts.

Why does Outreach2day score highest?

The criteria reward what we built: warm-up and sending inside the mailbox price and a low full-setup cost. We lose points for SMTP-only mailboxes, no blacklist monitoring and no free trial. The rules are published above, so you can re-weight them.

How often are these facts updated?

Checked Sep 28, 2026. Vendors change prices often. Found an outdated price? Email support@outreach2day.com and we'll fix it.

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.

  • Review your domains, DNS records and current inbox placement
  • Size the setup: domains, mailboxes per domain and daily volume per mailbox
  • Plan warm-up and the move from your current provider or sequencer

Free call.

See open times in your time zone and book without leaving the page.

Or open the booking page

Sources

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

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