Creating 100 email accounts sounds simple… until you actually try doing it.
I’ve tested this firsthand.
Manual setup? Too slow. Cheap tools? Got flagged.
One inbox got shut down before I even hit send. An automated setup can save time and reduce errors when configuring email authentication protocols like DKIM, SPF, and DMARC.
Mastering the cold email game means using the right tools and strategies to ensure your cold email outreach lands in inboxes, not spam, and your campaigns actually succeed.
That’s when I started using tools like Mailscale. It creates and warms up email accounts — automatically — so you don’t burn your sender reputation.
And while Mailscale works well for some teams, it’s not perfect.
If you’re running a lead gen agency, outbound sales team, or just want more control over how your emails land, you need better options.
I personally tested 5 Mailscale alternatives to create and warm 100 email accounts — safely and reliably.
You’ll learn:
This isn’t theory. I tested these tools across 3 domains, tracked deliverability, and spent over 2 weeks monitoring results.
Let’s break it down — tool by tool — and find out what actually works.
If you’ve ever tried setting up 10, 20, or even 50 inboxes by hand, you know how quickly things get out of control.
That’s where comes in.
👉 So, what is Mailscale?
It’s a tool that automatically creates and warms up email accounts, so your cold emails avoid spam and actually reach people.
Mailscale streamlines the email setup process, making it easy for teams to get started with cold outreach efficiently. It automates the entire setup process, including configuring DKIM, SPF, and DMARC records, which significantly reduces manual effort and saves time.

It’s designed for cold outreach teams who want to scale without messing with manual setups or risking deliverability.
And for a lot of teams, that’s a huge time-saver.
It’s a good starting point if you just need to get a few accounts running fast.
When I tried to scale beyond 30–40 accounts, it started to fall short.

Read the full user review

Read the full user review
Because it’s simple.
If you’re just getting started and want something that works out of the box, Mailscale does the job. Unlike traditional methods that require manual setup and configuration of email domains and DNS records, Mailscale’s automated approach saves significant time and effort.
But if your goal is to generate 100+ warm inboxes, maintain full control, and optimize cold outreach, it’s probably time to look elsewhere.
That’s why I went out, tested other tools myself, and built a list of real alternatives that solve these gaps.
Next up — here’s what I looked for in a better solution.
Before I started testing other tools, I sat down and made a list.
If I were going to replace Mailscale — or recommend something better — the new tool had to do more than just “warm inboxes.” Deliverability control is a crucial factor when evaluating alternatives, as it ensures high inbox placement and campaign success. Proper deliverability and account setup are essential for effective email marketing, as they directly impact the success of your outreach efforts.
It had to solve the real problems that show up when you’re trying to scale cold outreach fast, across multiple domains, accounts, and campaigns.
So here’s exactly what I looked for.
This was non-negotiable.
A lot of warm-up tools expect you to create inboxes manually. But if you’re trying to set up 50 or 100 inboxes, you don’t want to waste hours doing it by hand.
Efficiently creating and managing multiple email accounts is crucial for scaling cold outreach and running effective campaigns. Tools that offer unlimited email inboxes provide maximum scalability, allowing you to manage high email volumes and multiple campaigns without extra costs.
✅ I wanted a tool that could create inboxes automatically — ideally across Gmail, Outlook, or custom domains.
Warmup isn’t just about sending random emails. Done wrong, it can trigger spam filters and ruin your sender score.
A safe and gradual warmup is essential for any successful cold email strategy, ensuring your emails are delivered and not marked as spam. These strategies are crucial for cold email success, as they improve deliverability and lead to better campaign outcomes.
So I looked for tools that:
I wanted a warmup that feels real, not something that gets flagged in the first week.
The last thing I wanted was a tool that just “runs in the background” with no feedback. I needed visibility into what was actually happening.
✅ A good dashboard should show:
If I can't see what's working (or what's broken), I can't trust the tool.
This was a big one.
With Mailscale, I felt boxed in. I couldn’t change the warmup speed, messaging, or scheduling. So I looked for tools that gave me control over:
Having more control over these factors means you can optimize your email outreach, ensuring your campaigns are more effective and scalable.
More control = fewer surprises down the road.
Let’s be real — pricing matters.
Some tools look cheap on the surface, but the moment you add more inboxes, the price explodes.
I wanted pricing that actually made sense for scaling to 50, 100, or even 200 inboxes.
✅ Tools that offered:
When planning your cold email campaigns, understanding both domain cost and mailbox cost is essential for effective budgeting and scaling. Factoring in the per-domain annual fee and per-mailbox setup or maintenance costs helps ensure your email infrastructure remains cost-effective as you grow.
Cold outreach already costs time and effort. The tech shouldn’t eat half your budget.
I didn’t want a standalone warmup tool. I wanted a software tool that I could connect with the rest of my cold outreach stack — like CRMs, Google Workspace, or cold email platforms. Choosing a software tool that integrates seamlessly with these platforms makes managing and scaling email campaigns much easier. Selecting the right email marketing tools is also crucial, as they can significantly improve deliverability, scalability, and overall campaign effectiveness.
Bonus points if it had:
The more I could automate, the better.
To save you hours of research, I personally tested five of the most talked-about cold email tools for creating and warming up cold email accounts. These five cold email tools were selected for their ability to streamline outreach and improve deliverability.
Here’s the full list of tools we tested:
Additionally, Mission Inbox is another specialized cold email infrastructure provider worth considering. It focuses on deliverability, dedicated IP management, and offers tools tailored for lead generation agencies.
To make it easier for you to compare, I’ve created a simple table below, so you can quickly see what each tool offers and which one might fit your setup best.
InfraForge is a fully automated cold email infrastructure tool that creates, configures, and warms inboxes without any manual setup. It provides a private infrastructure, ensuring greater control, security, and deliverability for your cold email campaigns.
No DNS headaches. No manual inbox creation. No confusing dashboards.

Set up and warm 100 inboxes across multiple domains — fast, safely, and without burning time on technical setup
InfraForge gives you everything you need to launch and run cold email campaigns — without doing any of the hard setup work yourself. Here's how it helps:
It creates your email accounts for you
Just tell it how many inboxes you need — it sets them up (Gmail, Outlook, or your own domain) without you logging in anywhere.
It sets up your domain automatically
No need to mess with DNS records or email settings. InfraForge handles everything so your emails look trusted and professional.

It warms up your inboxes safely
New inboxes can't start blasting cold emails. InfraForge sends smart, human-like emails in the background to build trust with inbox providers.
It spreads emails across multiple inboxes
Instead of using one inbox and getting flagged, it rotates your sending to keep each inbox safe and deliverability high.
It gives you one place to track everything
You can see which inboxes are healthy, if anything needs fixing, and how your warmup is going — no technical setup needed.
It scales easily if you grow
Whether you need 10 inboxes or 100, InfraForge keeps things simple. It's built for teams, agencies, and founders who just want it to work.

Per Domain:
$70/year (one-time charge for .com domains)
Per Inbox:
Let’s say you’re managing 5 domains and need 10 inboxes for your cold outreach setup:
👉 Total Annual Cost: $2,390/year
Includes inbox creation, domain setup, DNS config, automated warmup, rotation, and real-time alerts. InfraForge pricing also covers dedicated ip and dedicated ips options, which are essential for maintaining high deliverability and controlling sender reputation.

Warmforge is a dedicated warmup platform that keeps your emails out of spam by simulating human-like sending behavior.
It streamlines the technical setup required for cold emailing, making it easier to launch campaigns.
It doesn’t create inboxes or set up domains, but if your infrastructure is already in place, it’s a solid option to keep inboxes healthy.

Warmforge helps you maintain your sender reputation and protect your email reputation by warming up inboxes safely, using real-looking email activity. Here’s how it works:
It warms up the inboxes you already have. Just connect your Gmail, Outlook, or custom accounts — no setup headaches or extra tools needed.

It simulates natural email activity
Sends, opens, and replies to emails in a way that looks real, helping you avoid spam folders and improve your email reputation.
It checks your inbox settings for issues
Runs health checks on DNS and MX records to catch any technical problems before they affect deliverability.
It includes inbox placement testing
You get a free monthly test to see whether your emails are landing in inbox or spam.
It focuses only on warming — nothing else
A lightweight tool designed to keep your sender reputation and email reputation strong without doing too much.
It’s ideal if you already have inboxes set up
If you just need a warm-up and don’t want to switch tools, Warmforge fits in easily.

Let’s say you require 10 slots

Note: Unlike some competitors that rely on a shared IP infrastructure—which can negatively impact deliverability and increase spam risk—Warmforge avoids these risks by not using shared IPs.
Smartlead.ai is an all-in-one cold email tool that handles both inbox warmup and outreach campaigns on one platform. It makes it easy to build and manage cold email sequences for effective outreach.
You can create inboxes, warm them, send emails, and track replies — all from the same dashboard.
It’s great if you want everything under one roof without using separate tools for sending and warming.

Smartlead combines warmup, inbox rotation, and outreach into a single dashboard. Here’s how it helps:
It handles warmup and outreach in one place
No need for two tools — Smartlead lets you send campaigns and warm inboxes from the same dashboard.

It makes sequence building easy
You can set up follow-ups, delays, and personalization with a simple drag-and-drop interface.
It protects your inboxes with smart rotation
Emails are sent from multiple inboxes to avoid getting flagged and to keep things safe at scale.
It gives you real-time performance tracking
You'll see opens, replies, bounces, and spam issues as they happen — no guessing.
It needs very little setup to get started
There's no complex DNS configuration — just connect your inboxes and go.
It's great for teams that want to move fast
If you want to warm inboxes and run outreach campaigns in one place, Smartlead makes it simple.

Smartlead starts at $39/month, which includes outreach, warmup, and inbox rotation.
For teams that want both features without buying two tools, this pricing is hard to beat.
It’s a solid choice if you’re just starting cold outreach and want a single tool to handle it all.

Instantly.io is a cold email platform that offers built-in warmup and outreach features. It leverages dedicated servers to provide enhanced control, security, and scalability for high-volume cold email campaigns.
It’s designed for teams that want to send thousands of emails per day and need a tool that can scale.
It’s simple to use and works well for people who care more about volume and results than backend setup.

Instantly focuses on helping you send more emails with fewer limitations. Here's what it provides:
It’s built for high-volume cold email
Instantly is made for sending from dozens of inboxes daily — all managed in one place.

It warms up inboxes automatically
Warmup runs quietly in the background with no need to configure anything manually.
It rotates sending across multiple inboxes
This spreads out volume so you don’t overload any one account and risk spam issues.
It uses AI to time your sends smartly
Emails go out in a human-like way, helping you avoid triggering spam filters.
It shows you what’s working and what’s not
With live data on deliverability and inbox health, you always know what to fix.
It’s ideal if you're sending at scale
Whether you’re a team or a solo founder, Instantly simplifies large cold outreach.

Instantly starts at $37/month, which includes warmup, outreach features, and inbox rotation.
The more you send, the more value you get — it’s priced for teams that send at scale.

Note: Using a shared ip can increase the risk of deliverability issues and negatively impact your sender reputation. Dedicated solutions are preferable for serious cold emailers who want more control and reliability.
Mailivery is a dedicated email warmup tool built to improve deliverability and sender reputation.
It doesn’t create inboxes or handle campaigns, but if you already have your cold email system in place, it helps keep your emails out of spam.

Mailivery is all about warming inboxes safely and consistently. Here’s what it does:
It focuses entirely on inbox warmup
Mailivery is not a sending tool — it’s designed to build trust with inbox providers before you launch campaigns.
It warms up your inboxes using real activity
Emails are sent and replied to between real accounts to simulate genuine engagement.

It helps fix inboxes with poor deliverability
If you’re getting flagged or starting fresh, Mailivery helps rebuild your sender reputation.
It gives you inbox placement and health reports
You’ll know when your inbox is ready to start sending cold emails safely.
It doesn’t include any outreach features
It pairs well with other tools and focuses only on keeping your inboxes healthy.
It’s perfect for preparing new or risky domains
Great for agencies and teams who want clean inboxes before launching outreach.

Mailivery starts at $29/month, depending on your number of inboxes.
It’s more premium than some tools, but it’s laser-focused on getting your emails into inboxes.
If inbox health is your biggest concern, it’s worth it.

If you're using Gmail or Yahoo inboxes for cold outreach, not all tools handle them the same way.
Here's what we found during testing:
✅ InfraForge – Best for Gmail-based inbox creation
✅ Smartlead.ai – Good for both Gmail and Outlook inboxes
⚠️ Mailivery & Warmforge – Compatible, but BYO inboxes
These tools work with Gmail and Yahoo, but they don't create the accounts for you.
You'll need to manually set up your inboxes first, then connect them to start warmup.
If you're starting from scratch and want the easiest Gmail setup, InfraForge is your best bet. If you already have Gmail or Yahoo inboxes ready, the others will still get the job done, but expect a few more manual steps.
Not every team needs the same thing, so here's a quick way to figure out which tool fits your setup best.
Ask yourself:
If you’re unsure, here’s a simple rule:
👉 If you’re starting fresh and want to scale fast without dealing with technical setup, go with InfraForge.
It removes 90% of the work and lets you launch faster.
We set out to test these tools with a real goal in mind:
Set up and warm 100 email inboxes across multiple domains — fast, safely, and without technical headaches.
Here’s what we found:
If you need to scale fast, especially to 100 inboxes or more, InfraForge gives you everything in one place.
No extra tools. No tech blockers. Just better deliverability and faster cold outreach.
If you're trying to create and warm 100+ inboxes quickly, Mailscale might not be your only or best option.
There are tools now that do more, cost less, and give you way more control.
From all-in-one platforms like InfraForge that handle everything for you, to simple warmup tools like Mailivery and Warmforge, you’ve got smarter, faster, and more scalable alternatives.
If you’re just getting started or tired of patching tools together...
👉 Start with the InfraForge free trial.
It takes care of domains, inboxes, DNS, warmup, and rotation — no scripts, no tech hurdles.
You’ll go from idea to outreach-ready in a day — and never look back.