Best Cold Email Infrastructure Tools in 2026

The best cold email infrastructure tools for most small B2B teams in 2026 are MailReach, Warmup Inbox and TrulyInbox for warm-up and deliverability testing, and InboxKit, inboxy and Zapmail for cold email inboxes and domains.

These tools cover the email side of an outbound setup: sending inboxes, domain and DNS setup, warm-up, and checks on whether your emails land in the inbox. ZenMode handles the LinkedIn side of the same setup (connection requests, messages and follow-ups).

Tools are ordered by fit for small B2B sales teams and founders who also do LinkedIn outreach. Pricing is taken from each tool's own site as of October 2026, so check before you buy.

Quick comparison

Warm-up and deliverability testing

1. MailReach

Email warm-up, spam tests, a deliverability co-pilot and an email verifier in one tool.

Key features: AI warm-up per mailbox, spam tests with seed lists, SPF/DKIM/DMARC and blacklist checks

Pricing: $19.50 per mailbox/month billed monthly (warm-up plus 20 spam test credits); annual billing saves 20%. No free plan or trial listed.

Best for: Cold emailers who want warm-up and spam testing in one tool

Watch out for: Reviewers say the dashboard gets confusing with many inboxes, and warm-up pacing isn't very customizable.

Website: mailreach.co

2. Warmup Inbox

A warm-up network that exchanges opens and replies between real inboxes to build sender reputation.

Key features: Network of 30,000+ real inboxes, plans up to 1,000 warm-up messages/day per inbox, REST API for partners

Pricing: Free forever plan (unlimited inboxes, 15 warm-up emails/week). Basic is $15 per inbox/month billed monthly or $180 per inbox billed yearly, with 75 warm-up messages/day. 7-day full trial, no card.

Best for: Small teams warming a handful of inboxes cheaply

Watch out for: Per-inbox pricing adds up with many mailboxes, and the free tier is only 15 warm-up emails a week.

Website: warmupinbox.com

3. TrulyInbox

Email warm-up with a deliverability score and health checks. Paid plans are priced by email volume with unlimited accounts.

Key features: Unlimited accounts on paid plans, deliverability score and health checks, partner API

Pricing: Free plan (1 account, 10 warm-up emails/day). Starter is $29/month billed monthly or $22/month billed annually, with 200 warm-up emails/day. 7-day trial on paid plans.

Best for: Teams with many inboxes who want volume-based pricing

Watch out for: The free plan is limited to 1 account and 10 warm-up emails a day, so real use needs Starter or above.

Website: trulyinbox.com

4. Mailivery

Peer-to-peer AI email warm-up with blacklist monitoring and inbox placement tests.

Key features: Unlimited mailboxes on a shared daily volume, blacklist monitoring, inbox placement tests and verification credits

Pricing: Starter $29/month billed monthly ($21.75/month billed yearly), 200 warm-up emails/day shared. 7-day free trial on all paid plans.

Best for: Agencies warming many mailboxes on a shared daily volume

Watch out for: Small review base (7 on Capterra). Reviewers want more deliverability analytics, and one reported a 7+ day outage with no proactive communication.

Website: mailivery.io

5. EmailGuard

Deliverability and authentication monitoring, with some features built for cold outreach.

Key features: Blacklist and DMARC monitoring, inbox placement tests and spam checks, domain masking proxy and hosted redirects

Pricing: Free forever plan (1 domain, 3 email accounts, 50 verification credits/month, 10 spam-filter tests). Pro is $49/month.

Best for: Cold email agencies monitoring many domains

Watch out for: One editorial review notes no webhooks for alerts and low verification credits for high-volume list work. A dedicated redirect IP is an extra $100/month.

Website: emailguard.io

6. Warmy

Email warm-up plus inbox placement tests, seed lists, DMARC monitoring and an AI deliverability assistant.

Key features: AI warm-up (Adeline AI), inbox placement tests and seed lists, domain health, blacklist and DMARC monitoring

Pricing: Plans start from $49/month billed monthly, based on volume. 7-day free trial, no card.

Best for: Cold emailers protecting sender reputation

Watch out for: The pricing page doesn't list mailbox counts or send limits per plan, so you need to confirm allowances with their team.

Website: warmy.io

7. GlockApps

Inbox placement and spam testing, plus reputation, blocklist and DMARC monitoring.

Key features: Placement and spam tests across providers, DMARC analytics (DMARKOFF) and reputation monitoring, blocklist and uptime monitoring

Pricing: Free plan with 2 spam test credits. Essential is $59/month billed monthly or $708/year billed annually, with 360 spam test credits.

Best for: Senders who need inbox placement tests plus DMARC monitoring

Watch out for: The free plan has only 2 spam test credits; real testing starts at $59/month.

Website: glockapps.com

8. Suped

A DMARC platform that turns DMARC reports into guided fixes for authentication and deliverability.

Key features: DMARC report monitoring with guided fixes, SPF/DKIM/BIMI setup help, multi-tenant management for MSPs

Pricing: Free plan (1 domain, 1,000 emails/month). Business is $19/month billed annually ($24/month reference price), with 100,000 emails/month and 2 domains.

Best for: SMBs and MSPs setting up and monitoring DMARC

Watch out for: The free plan covers only 1 domain and 1,000 emails a month, with 14-day data retention.

Website: suped.com

9. Unspam

A spam checker with authentication and blacklist checks, rendering previews and inbox placement previews.

Key features: Spam score and authentication/blacklist checks, inbox placement and device rendering previews, email heatmaps and screenshots

Pricing: Free account with 21 tests/month. The paid Custom plan is pay per test from a $5 monthly minimum; annual billing saves 15%.

Best for: Checking spam score and rendering before sending

Watch out for: The free plan allows only 5 spam tests a month with 14-day data retention, and per-test paid rates aren't published.

Website: unspam.email

10. MailGenius

A free email spam and deliverability tester, plus done-for-you deliverability consulting.

Key features: Free spam test with no account, SPF/DKIM, blacklist and HTML checks, deliverability consulting

Pricing: The basic spam test is free. For paid plans, see their pricing page.

Best for: Quick free spam tests and deliverability consulting

Watch out for: Pricing isn't transparent, and it has only 2 reviews on Capterra.

Website: mailgenius.com

11. VitaMail

A cold email tool with email validation and list cleaning, AI email writing, deliverability checkers and campaign sending.

Key features: Email validation and list cleaning, AI email writing, deliverability checkers and campaign sending

Pricing: See their pricing page.

Best for: SMBs running cold email campaigns

Watch out for: It's email only, with no LinkedIn channel.

Website: vitamail.vitanur.com

12. Mailwarm

Email warm-up through a network of real inboxes, with placement tracking and calls with a deliverability expert.

Key features: Warm-up via real inboxes, inbox placement tracking, monthly call with a deliverability expert

Pricing: Starter $69/month billed annually (1 mailbox, up to 50 warm-up emails/day). No free plan or trial.

Best for: Founders warming one or a few important mailboxes

Watch out for: Starter covers only 1 mailbox, and Capterra reviewers mention missing provider integrations and a weak UI.

Website: mailwarm.com

13. Folderly

A B2B deliverability platform with setup checks, inbox placement tracking and campaign drafting.

Key features: Setup checks and DNS/authentication fixes, inbox placement tracking (Inbox Insights), AI campaign drafting and DMARC tools

Pricing: Core Folderly is $96 per mailbox/month on a yearly plan. Inbox Insights is $79/month billed monthly (100 tests), with a free tier of 2 tests/month.

Best for: B2B sales teams fixing deliverability at scale

Watch out for: Pricey for small teams, and the core plan has no free trial.

Website: folderly.com

14. InboxAlly

An engagement-based deliverability tool that works with your existing ESP and uses seed inboxes to train spam filters.

Key features: Seed inbox interactions to train filters, works with your existing ESP, free spam checker and DMARC/SPF generators

Pricing: Starter $149/month billed monthly (100 seed emails/day, 1 sender profile). 10-day free trial, no card.

Best for: Email marketers who need to repair sender reputation

Watch out for: Expensive entry point for 1 sender profile and 100 seed emails a day.

Website: inboxally.com

Cold email inboxes and domains

1. InboxKit

Google Workspace, Microsoft 365 and Azure outreach mailboxes with automated DNS and warm-up.

Key features: Google, Microsoft 365 and Azure mailboxes, automated DNS setup, InfraGuard deliverability monitoring

Pricing: $3.00 per mailbox/month billed monthly or $2.50 billed annually, no minimum. Free account; first month of InfraGuard is free.

Best for: Outbound teams buying mailboxes one at a time

Watch out for: No free trial, and Azure tenants cost an extra $30 per tenant/month.

Website: inboxkit.com

2. inboxy

Google Workspace cold email mailboxes with DNS setup and connection to your sequencer.

Key features: Google Workspace mailboxes, automated SPF/DKIM/DMARC setup and sequencer connection, warm-up add-on

Pricing: $3.00 per mailbox/month billed monthly ($2.40 on yearly billing). Warm-up is a separate $3 per inbox/month.

Best for: Cold emailers who want cheap pre-configured Google mailboxes

Watch out for: Warm-up isn't included in the mailbox price, and there's no free trial.

Website: inboxy.io

3. Zapmail

Google and Microsoft cold email mailboxes with automated DNS, a pre-warmed option and an API.

Key features: Google Workspace and Microsoft mailboxes, automated SPF/DKIM/DMARC setup, pre-warmed mailboxes and API (Pro plan)

Pricing: Starter $39/month billed monthly, including 10 mailboxes (extra mailboxes $3.50 each). Quarterly and yearly billing available.

Best for: Agencies spinning up many cold email inboxes fast

Watch out for: No free trial, API access only on the $299/month Pro plan, and Google Workspace mailboxes are repriced after their first year.

Website: zapmail.ai

4. Cheap Inboxes

Low-cost Google Workspace and Microsoft cold email mailboxes with automated setup and an API.

Key features: Google Workspace and Azure/Microsoft inboxes, export to sequencers, developer API for domains, inboxes and DNS

Pricing: Google inboxes $3.50 per inbox/month (1-99 inboxes), flat monthly, no contract. Azure is $20 the first month, then $18/month for up to 100 inboxes on one domain. Domains extra from $2.50/year.

Best for: Lowest-cost bulk cold email inboxes

Watch out for: Thin review base (29 on Trustpilot), with one reviewer reporting emails landing in spam. Support runs mostly through WhatsApp, with no contact page.

Website: cheapinboxes.com

5. Premium Inboxes

Done-for-you Google Workspace and Microsoft 365 cold email inboxes, domains and DNS.

Key features: Done-for-you Google and Microsoft inboxes, domain purchase and DNS setup, inbox replacement and API access

Pricing: Start Up is $3.50 per inbox billed every 4 weeks (for example, 30 inboxes for $105); "Insured" is $4.50 per inbox. Annual billing saves 20%.

Best for: Agencies wanting done-for-you cold inboxes

Watch out for: No free trial, and pricing is shown inconsistently across the site.

Website: premiuminboxes.com

6. ScaledMail

Managed cold email inboxes, domains, DNS and deliverability for outbound teams.

Key features: Managed Google, Microsoft and SMTP inboxes, domain registration and DNS authentication, deliverability monitoring with Slack support

Pricing: Google Workspace $3.50 per mailbox/month, SMTP $3.75 per domain/month, Microsoft $50 per domain/month. Free account, no card.

Best for: Outbound teams wanting managed inbox setup with Slack support

Watch out for: Low sending caps per mailbox (up to 25 emails/day on Google, 10/day on Microsoft and SMTP), and reporting is an extra add-on.

Website: scaledmail.com

7. Icemail

US-IP Google and Microsoft cold email mailboxes with automated DNS.

Key features: US-IP Google Workspace and Microsoft 365 mailboxes, automated DKIM/SPF/DMARC and AI domain finder, one-click export to sequencers

Pricing: $2.50 per mailbox/month billed monthly (labelled a limited deal, with $3.50 shown alongside), no lock-in.

Best for: Budget-conscious cold emailers needing many mailboxes fast

Watch out for: Billing is from a prepaid wallet; if it runs out, mailboxes are deleted and reactivation fees apply. A Trustpilot reviewer reported mailboxes disconnecting every few days.

Website: icemail.ai

8. Aerosend

Private cold email sending infrastructure with dedicated IPs, managed warm-up and burn alerts.

Key features: Dedicated and aged IPs, domain burn alerts and biweekly inbox placement tests, integrations with common sequencers

Pricing: $4 per inbox/month for the first 150 inboxes ($2 after), billed monthly, no contract. Recommended minimum is 30 inboxes ($120/month).

Best for: Agencies scaling cold email that want managed private infrastructure

Watch out for: G2 reviewers mention email-only support, some UI bugs and missing deliverability graphs.

Website: aerosend.io

9. Mission Inbox

Dedicated sending infrastructure and IPs for sales email, via API, SMTP or mailboxes.

Key features: Dedicated IPs and isolated sending environments, MI Shield pre-send checks, API, SMTP and pre-warmed mailboxes

Pricing: Lite $50/month billed monthly (15 mailboxes, 5,000 sends/month). For a free plan, see their pricing page.

Best for: Teams wanting dedicated-IP sending for sales email

Watch out for: Lite caps you at 5,000 sends a month, and going over means pausing the account and upgrading. Warm-up emails count as sends.

Website: missioninbox.com

10. Maildoso

Cold outreach mailboxes and domains with auto DNS, sequencer sync, API and MCP.

Key features: Pay-per-mailbox mailboxes and domains, auto DNS and IP rotation, API and MCP on every plan

Pricing: 30 mailboxes for $75/month billed monthly ($2.50 per mailbox). No free plan or trial; 30-day money-back guarantee.

Best for: High-volume cold emailers needing cheap mailboxes

Watch out for: Plans list up to 15 emails a day per mailbox, and the smallest monthly plan is 30 mailboxes.

Website: maildoso.ai

11. Inframail

Cold email inboxes on your own domains for a flat fee, with auto SPF/DKIM/DMARC and export to sequencers.

Key features: Unlimited inboxes on your own domains, automatic SPF/DKIM/DMARC setup, export to sequencers

Pricing: Unlimited Plan $147/month billed monthly (recommended up to 400 mailboxes, 10 free domains, 1 dedicated US IP).

Best for: Agencies wanting flat-fee unlimited inboxes

Watch out for: No native warm-up and no sending, so you need a separate sequencer and warm-up tool.

Website: inframail.io

12. Mailreef

Dedicated cold email servers, mailboxes and domains with automated setup and monitoring.

Key features: Dedicated servers with 150+ mailboxes each, automated domain and DNS setup, deliverability monitoring

Pricing: Agency $240/month on a 12-month commitment, or Agency Flex $249/month month-to-month, both plus $0.001 per send.

Best for: Agencies sending high cold email volume on dedicated servers

Watch out for: High entry cost for small senders.

Website: mailreef.com

How to choose

For a few sending inboxes, a per-mailbox provider (InboxKit, inboxy, Zapmail) plus a low-cost warm-up tool (MailReach, Warmup Inbox, TrulyInbox) is generally enough for a small team.

Check whether warm-up is included. inboxy charges for it separately, and Inframail has none.

Look at daily send caps per mailbox (ScaledMail, Maildoso, Mission Inbox) and work out how many mailboxes your volume needs.

Run an inbox placement test before a new campaign. GlockApps, Unspam, MailGenius and EmailGuard all have free tests.

Mailreef, Inframail, Folderly and InboxAlly are priced for agencies and high volume.

Using it with LinkedIn outreach

ZenMode runs the LinkedIn side of outbound: connection requests, messages, follow-ups and voice notes (Practitioner and up), with every reply in one inbox. The tools above handle the email side. If you work the same leads on both channels, ZenMode's HubSpot integration syncs contacts, deals and notes both ways on every plan, so LinkedIn activity sits in the same CRM as your email activity.

ZenMode's Signals finds people showing buying intent, such as engaging with a competitor's posts, hiring, changing jobs or raising funding, and writes each one a message. Signals is included on every plan except Novice.

Want LinkedIn outreach that writes the messages and keeps every reply in one inbox? Start free trial.

FAQ

What are cold email infrastructure tools?

Cold email infrastructure tools are the inboxes, domains and deliverability tools behind cold email sending. That covers inbox and domain providers (like InboxKit or Zapmail), warm-up tools (like MailReach or Warmup Inbox), and testing and monitoring tools (like GlockApps or Suped). You still need a separate sequencer to send the campaigns.

How much do cold email inboxes cost?

Most per-mailbox providers here charge around $2.50 to $4 per mailbox/month. InboxKit and inboxy start at $3.00, Cheap Inboxes and ScaledMail at $3.50 for Google mailboxes, and Aerosend at $4. Flat-fee and dedicated-server options like Inframail ($147/month) and Mailreef ($240/month plus per-send fees) cost more upfront.

Is there a free email warm-up tool?

Yes, Warmup Inbox and TrulyInbox both have free forever plans. Warmup Inbox's free tier allows 15 warm-up emails a week, and TrulyInbox's allows 1 account with 10 warm-up emails a day.