8 Best Cold Email Infrastructure Tools I Tested

I spend a lot of my time working with cold email campaigns, and I’ve learned that infrastructure matters more than most people think.

It’s the email infrastructure behind your campaigns, including the domains, mailboxes, DNS records, and IPs your emails are sent from. If the setup is poor, even great copy won’t save your campaigns.

The problem is that every provider offers infrastructure differently. You’ll find options with shared IPs, dedicated servers, Google Workspace accounts, unlimited inboxes, and more.

So how do you know which provider is actually right for your needs?

After working with cold email for almost five years, I’ve learned what makes an infrastructure setup reliable. I looked at setup time, DNS configuration, actual costs, and where the first emails landed.

These are the cold email infrastructure providers I’d recommend.

TL;DR: My Top Cold Email Infrastructure Picks

Short on time? Start here:

• Best affordable starting point: Mailforge offers shared infrastructure, pre-warmed email accounts, automated DNS setup, and mailbox provisioning in under five minutes.
• Best for control at scale: Infraforge offers dedicated IPs for each mailbox, pre-warmed infrastructure, white-label support, and workspaces for separating clients.
• Best for matching your prospect’s provider: Primeforge offers real Google Workspace and Microsoft 365 mailboxes that match your prospects’ email service providers.
• Best for low-cost mailbox infrastructure: Maildoso keeps mailbox costs low while giving you automated DNS setup and API access on every plan.
• Best for flat-rate email infrastructure: Inframail offers unlimited inboxes under one monthly price, with dedicated US IPs included across its plans.

The full 8-tool comparison is below:

8 Cold Email Infrastructure Tools Compared

Scroll sideways to see every column.

How I Tested These Cold Email Infrastructure Providers

Here are the seven checks I used for every provider:

• How long does it take to get a working mailbox? I timed everything from signup to the first successful test send.
• Are SPF, DKIM, and DMARC set up correctly? I checked the DNS records manually instead of relying only on the provider’s dashboard. I used our DNS setup guide for cold email as a reference.
• What does 25 mailboxes actually cost? I included domains, SSL, and warmup in the total.
• Where does the first email land? I ran inbox placement testing across Gmail and Outlook before starting any real campaign.
• Can I manage different clients separately? I created three test client workspaces with each provider.
• Can the setup be automated? I tested the API and MCP where available.
• What happens if a domain gets flagged? I checked the monitoring, alerts, and support available for each provider.

The 8 Best Cold Email Infrastructure Tools

Here is the list of providers I recommend for cold email infrastructure:

1. Mailforge: Best for Affordable Shared Infrastructure

Best for: GTM teams and agencies that want to scale cold email without managing the infrastructure themselves.

Mailforge provides shared email infrastructure for cold outreach.

You can buy domains and mailboxes through the platform or bring your own, while Mailforge handles the technical setup.

You enter your target sending volume, and Mailforge recommends how many domains and mailboxes your email infrastructure setup needs.

I find this useful for smaller teams that do not want to deal with servers or DNS settings themselves.

The shared IP setup keeps the cost lower than private infrastructure and makes it easier to add more mailboxes as your campaigns grow.

The downside is that you share the sending environment with other customers.

Key Features

• Pre-warmed mailboxes: Start sending without paying a separate warmup fee.
• Bulk domain and mailbox creation: Create multiple domains and mailboxes from one cold email infrastructure setup flow.
• Automated DNS: Get automated setup of SPF, DKIM, DMARC, and tracking domains, with no manual domain setup.
• Workspaces: Keep multiple clients and projects separate in their own workspaces.
• MCP, CLI, and API: Create and manage domains and mailboxes through your own workflows and tools such as Claude and Cursor.
• Any sending platform: Connect your mailboxes to the sending tool you already use.
• Domain forwarding: Point sending domains to your main website from inside Mailforge.
• Domain transfer: Bring your own domains or move them out later without platform lock-in.
• SSL and domain masking: Add secure, branded pages to your sending domains.

Mailforge Pros and Cons

Mailforge Pricing

2. Infraforge: Best for Dedicated IPs and Control at Scale

Best for: Agencies and high-volume teams that want dedicated IPs and more control over sender reputation.

Infraforge provides private email infrastructure for cold outreach, with each mailbox running on dedicated infrastructure and its own IP.

This keeps your sending activity separate and gives you more control over sender reputation.

I find it a good fit for agencies and larger teams that manage several clients or run high-volume outreach. You can keep different client setups separate while managing them from one account.

The best part is the setup. Infraforge handles the technical work for you, including email authentication and domain configuration.

You can have your infrastructure ready in about five minutes.

Pre-warmed infrastructure is also available if you want to start sending without going through the usual warmup period.

The pricing is higher than shared infrastructure because you pay separately for dedicated IPs, servers, and some add-ons.

Key Features

• Pre-warmed mailboxes: Start with mailboxes that have already gone through the warmup process.
• Multi-IP provisioning: Set up separate IPs for different clients, campaigns, or sending needs.
• Bulk generators: Create multiple domains and mailboxes at the same time.
• Smart sending limits: Set sending limits for individual mailboxes.
• Masterbox: Manage replies from multiple mailboxes in one place.
• Workspaces: Keep different clients and projects separate.
• White-label option: Offer the platform under your own brand.
• API access: Create and manage unlimited mailboxes and domains through the API.
• MCP access: Connect Infraforge with AI assistants and MCP-compatible tools.

Infraforge Pros and Cons

Infraforge Pricing

Infraforge uses per-mailbox pricing that drops as volume grows, billed annually.

3. Primeforge: Best for Google Workspace and Microsoft 365 Mailboxes

Best for: GTM teams and agencies whose prospects use Gmail or Outlook and who want to send through the same providers.

Primeforge provides real Google Workspace and Microsoft 365 mailboxes for cold outreach.

This lets you send from the same providers your prospects use, which is what Primeforge refers to as ESP matching.

Primeforge uses standard Google and Microsoft accounts rather than repurposed inboxes or EDU accounts. It also handles SPF, DKIM, and DMARC setup for you, so you do not have to configure each domain yourself.

I also like the setup speed. The first mailbox is usually ready in about 30 minutes, and pre-warmed mailboxes are available for teams that want to start sending right away.

The main downside is the price. Primeforge is the most expensive of the three Forge products on a per-mailbox basis.

Key Features

• Real Google Workspace and Microsoft 365 mailboxes: Use genuine accounts from Google and Microsoft for your outreach.
• ESP matching: Match your sending provider with your recipient’s provider to land in the primary inbox more often.
• Pre-warmed mailboxes: Start with mailboxes that have already been warmed up.
• Mailbox profile branding: Get profile pictures and GIFs set up on each mailbox before you start sending.
• Automated DNS setup: Primeforge configures SPF, DKIM, and DMARC for your domains.
• MCP and CLI: Manage mailboxes and domains through MCP-compatible tools and command-line workflows.

Primeforge Pros and Cons

Primeforge Pricing

4. Maildoso: Best for Affordable Mailboxes at Scale

Best for: Lead generation teams and high-volume senders that need a large number of mailboxes without Google or Microsoft accounts.

Maildoso provides SMTP mailboxes that run on its own SMTP servers. You choose your domain and mailbox names, and Maildoso handles the technical setup, including SPF, DKIM, and DMARC.

I find it useful for teams that need a large mailbox setup without relying on Google Workspace or Microsoft 365. The mailboxes can also be connected to platforms such as Instantly, Smartlead, and Saleshandy without much setup.

Maildoso also offers API and MCP access on every plan, along with a money-back guarantee.

One feature I particularly like is CAPTCHA domain protection. It helps keep scanners from linking your sending domains to your main website.

The main limitation is the daily sending cap per mailbox. That means teams running larger campaigns may need more mailboxes to reach their target volume.

Key Features

• SMTP mailboxes at volume pricing: Scale mailbox count at some of the lowest per-mailbox prices available.
• Automated DNS setup: Get SPF, DKIM, and DMARC configured automatically on every domain.
• Self-healing mailboxes and IP rotation: Get flagged mailboxes recovered automatically and volume spread with sender rotation.
• Unified inbox: Read replies from every mailbox in one place instead of opening each inbox setup separately.
• Daily domain reputation checks: Score mailbox and domain health every day, and pause accounts before they burn.
• CAPTCHA domain protection: Block scanners from linking your primary domain to your outreach domains.
• API and MCP on every plan: Automate provisioning from code or an AI agent without upgrading tiers.

Maildoso Pros and Cons

Maildoso Pricing

5. Zapmail: Best Email Infrastructure Provider for Google Mailboxes

Best for: Freelancers and small agencies that want real Google Workspace mailboxes at a lower price.

Zapmail is an email infrastructure platform that offers both Google Workspace and Microsoft 365 mailboxes for cold outreach.

It handles the setup for you, including DNS, SPF, DKIM, and DMARC.

Each domain gets its own workspace, which keeps your mailboxes separate across domains. You can also connect them through OAuth instead of setting up app passwords yourself.

I like that Zapmail supports more than 50 sending tools. You can also buy pre-warmed mailboxes and aged domains as paid extras.

One feature worth mentioning is the AI setup tools. They can suggest domain names, create mailbox handles, and generate profile images for your senders.

The main limitation is that API access is only available on the Pro plan. Zapmail also does not offer MCP or CLI access.

Key Features

• Real Google Workspace mailboxes: Send from official Business Starter accounts, with Microsoft 365 available too.
• Workspace-level isolation: Keep each domain in its own workspace so one flagged mailbox cannot spread.
• Automated DNS and OAuth connection: Get records configured instantly and mailboxes connected without app passwords.
• Pre-warmed mailboxes and aged domains: Pay extra and start sending on day one.
• Deliverability test credits: Run placement checks monthly on every plan, at 3 on Starter, 10 on Growth, and 30 on Pro.

Zapmail Pros and Cons

Zapmail Pricing

6. InboxKit: Best for Warmup and Monitoring in One Place

Best for: Agencies and SDR teams that want mailbox setup, warmup, and monitoring from the same provider.

InboxKit provides mailboxes through official Google, Microsoft, and Azure tenants. You can handle provisioning, warmup, and monitoring from the same platform.

Its warmup system works on an individual mailbox basis rather than using a shared pool. This keeps each mailbox separate during the warmup process. InboxKit also sets up DNS in under 60 seconds, and every plan includes unlimited users.

I also like InfraGuard, which checks deliverability, blacklist status, and DNS health. The first month is free, so you can test it before adding another recurring cost.

InboxKit can save you from managing separate tools for mailbox setup, warmup, and monitoring. The main limitation is that warmup costs extra, which matters when you have a large number of mailboxes.

Key Features

• Official Google, Microsoft, and Azure provisioning: Create mailboxes on real provider tenants from one dashboard.
• Isolated warmup: Warm each mailbox independently rather than through a shared pool, at $3 per mailbox per month.
• InfraGuard monitoring: Track deliverability, blacklists, and DNS health, with the first month free.
• Automated DNS configuration: Get SPF, DKIM, and DMARC set up with US-based IP assignment.
• 24+ sequencer integrations: Connect to your existing sending tool without manual export.

InboxKit Pros and Cons

InboxKit Pricing

7. Mailpool: Best for Running Several Provider Types at Once

Best for: Ops teams that want SMTP, Google, and Microsoft mailboxes managed from one dashboard.

Mailpool lets you manage different types of email infrastructure from one dashboard. You can use SMTP, Google Workspace, Microsoft 365, and dedicated servers without managing separate platforms.

I like this setup for teams that want to spread their sending across different providers. If one provider runs into an issue, you can keep other mailboxes active and protect reliable inbox placement. Mailpool also reports more than 3,000 customers, 35,000 domains, and 250,000 inboxes created.

The platform also has Google Cloud and Microsoft partner status, which adds another layer of provider support to the setup.

One feature worth mentioning is the AI domain generator. It helps you find available domains without checking them one by one.

Mailpool makes sense when you want different mailbox types in one place. The main limitation is that volume discounts only start once you reach 100 mailboxes.

Key Features

• Multi-provider mailbox creation: Run SMTP, Google Workspace, Microsoft 365, and dedicated server mailboxes from one dashboard.
• Automated authentication: Get SPF, DKIM, and DMARC configured across every provider type.
• AI domain generator: Get available domain names suggested rather than checking a registrar by hand.
• Blacklist monitoring: Get alerted when a domain or IP lands on a blacklist.
• API on all plans: Automate provisioning without upgrading, with extended access on dedicated infrastructure.

Mailpool Pros and Cons

Mailpool Pricing

8. Inframail: Best for Buying Email Infrastructure at a Flat Rate

Best for: Lead generation agencies that manage many mailboxes and want one monthly price.

Inframail provides Microsoft-based email infrastructure for teams that manage a large number of inboxes. You pay a flat monthly fee, with the number of inboxes depending on your plan.

I find it useful for agencies that have moved beyond a small mailbox setup. You can also buy domains through the platform and have new inboxes ready within minutes.

Inframail includes dedicated US IP addresses with its plans, giving you a separate sending setup for your outreach.

One feature worth mentioning is Phantom Redirect. It keeps your domain redirects separate from your main domain, so your sending domains appear as independent websites to email providers.

The main limitation is the sending cap. Even the Unlimited plan has a monthly sending limit, so it is worth checking that against your expected email volume.

Key Features

• Unlimited email inboxes on a flat fee: Connect unlimited email accounts with no extra cost per inbox.
• Dedicated US IP addresses: Send on your own IP, at one on the Unlimited plan and three on the Agency Pack.
• Automated DNS setup: Get SPF, DKIM, and DMARC configured automatically on every domain.
• Real-time deliverability monitoring: Watch IP and domain health on one dashboard. Its site reports auto-submit delisting requests at a 68.3% success rate.
• Phantom Redirect feature: Hide domain redirects from email service providers, so secondary domains look like independent sites.
• Custom tracking domain: Add a tracking domain to every inbox, set up automatically for the sending tool you use.
• Deliverability consultant: Call a named person when inbox placement drops. Email warm up is not included, so budget for a separate warmup tool.

Inframail Pros and Cons

Inframail Pricing

Overall, Inframail is right when you run 100+ inboxes and count cost per inbox, and wrong when your prospects are mostly on Gmail.

How to Choose Cold Email Infrastructure

Run your shortlist through these questions. Each one separated the eight tools above.

• How many emails a month do you send, and how many mailboxes does that need at 30 a day?
• Do you run email verification on your list before you launch cold email campaigns?
• Do you need to send this week, or can you warm for a month?
• Are your prospects mostly on Gmail, on Outlook, or mixed?
• Is warmup included, or do you warm up every mailbox through a separate tool?
• Do you need one client separated from another?
• What does the bill look like at three times your current volume, and which advanced features are only on the higher plan?
• Are domains included in the price, or billed at extra cost?
• Can you provision from code or an AI agent, or is it click-only?
• What is the daily sending cap per mailbox once you scale outreach?
• Who owns the domains if you leave?
• Does the provider tell you about a blacklist, or do you find out from your reply rate? Our guide to recovering a blacklisted IP covers what happens next.
• What happens in month 13, and is renewal pricing published?

Starting Your Cold Email Infrastructure Journey? Here’s a Tip

If you want reliable infrastructure for your cold email campaigns, I recommend starting with Infraforge. It gives you dedicated infrastructure, pre-warmed mailboxes, and more control over your sending environment.

My recommendation is simple: try Infraforge and get your cold email infrastructure set up without the usual technical hassle.

If you are still unsure, explore the other infrastructure options we covered in this guide to find the right fit for your needs. Whichever you pick, pair it with a cold email outreach tool that handles multi channel outreach, so your mailboxes are actually put to work.

FAQs About Cold Email Infrastructure Tools

1. Should I use shared IPs or dedicated IPs for cold email?

Use shared IPs when you are starting out, and dedicated IPs once you send enough to build a reputation on your own. Shared pools spread the risk across many senders, which protects a small sender and exposes a careful one. If you send under 5,000 emails a month, dedicated IPs will not help you yet.

2. Should I run two mailbox providers at the same time?

Yes, and it is the most useful piece of infrastructure advice I can give you. Two providers mean you always have a matching mailbox for whichever inbox your prospect uses. It also means one provider having a bad week does not stop your outreach.

3. How many mailboxes do I need to send 10,000 emails a month?

You need roughly 10 to 15 mailboxes, based on 30 to 50 emails per mailbox per day. Fifteen mailboxes at 30 sends a day gives you about 13,500 a month with headroom. Spread those across at least five domains, and do not run them at full volume until warmup finishes.

4. What is the cheapest cold email infrastructure tool?

Maildoso is cheapest at volume, dropping to $0.49 per mailbox on the 1,000-mailbox package. Mailforge is the cheapest entry point at $30 a month for 10 mailboxes. There is no truly free cold email software here, though Maildoso offers a 30-day money-back guarantee. None of these cold email tools send campaigns for you, so add the cost of a cold email platform, a cold email automation tool, or another outreach platform on top.

5. Do pre-warmed mailboxes work, or do I still need warmup?

Pre-warmed mailboxes let you send on day one, but you still need warmup running afterwards. Sender reputation is ongoing rather than a box you tick once. They are worth the extra cost when speed matters, such as a client launch or replacing a burned domain.