Mailsim
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Email Simulation Platform

Warm Up Your Email.
Land in Every Inbox.

Stop overpaying for email warming. Mailsim delivers automated sender reputation building, advanced deliverability testing, and real-time tracking — all at a fraction of the cost.

Start Warming Now

Why teams switch to Mailsim

Other warming tools charge a premium for basic features and lock advanced tools behind expensive tiers. We don't.

Self-Service Onboarding

Sign up, connect your email, and start warming in minutes. No sales calls, no demos, no waiting for approval.

Simple, Affordable Pricing

One straightforward plan. No confusing tiers, no hidden fees, no surprise charges. Pay less, get more.

Advanced Deliverability Tests

Send your own custom email templates from Gmail, Outlook, Mailgun, or any mail client directly to our test mailboxes — protected by enterprise-grade security filters including Proofpoint and Microsoft Exchange. See exactly how advanced spam filters evaluate your emails with full SPF, DKIM, DMARC, and CompAuth analysis, spam confidence scoring, blacklist checks, and inbox vs. junk placement results. All included at no extra cost.

Automated Warming

Connect your email and our system handles everything — sending, receiving, and engaging to build your reputation naturally.

Gradual Ramp-Up

Smart volume control starts slow and gradually increases, mimicking natural email behavior to avoid triggering spam filters.

Reputation Tracking

Monitor your sender reputation score, email activity, and deliverability metrics with a real-time dashboard.

Easy integration with your mailboxes

Mailsim supports email warm up for Gmail, Outlook, Yahoo, Zoho, and major email service providers, including SendGrid and other SMTP-based platforms.

Google
Outlook
Y!Yahoo
AWSAWS SES
SendGrid
Mailgun
Other SMTP

How we compare

Everything included. No feature gating. No tier upgrades.

FeatureMailsim.ioOthers
Self-service signupContact sales / demo required
Simple pricing
Custom template deliverability testingPaid add-on / higher tier
SPF / DKIM / DMARC analysisLimited or higher tier
Blacklist monitoringHigher tier only
Gradual ramp-up controls
Reputation tracking
No feature gating

What our users say

Real results from real email senders.

“

We were landing in spam on nearly every cold outreach campaign. After two weeks of warming with Mailsim, our inbox placement went from 40% to over 90%. Completely changed our pipeline.

Jessica Harmon
Head of Outreach, BrightLoop
“

The deliverability testing alone is worth the subscription. Being able to send a real template and instantly see SPF, DKIM, and blacklist results saved us from a major campaign blunder.

Marcus Chen
Email Marketing Manager, Oakstone Partners
“

We onboarded 12 new sender domains in one afternoon. No demos, no sales calls, no waiting. Just signed up and started warming. This is how SaaS should work.

Priya Kapoor
Founder & CEO, Nexova

Trusted By

Rivian TechPolaris MediaNexovaClearPath CRMDriftwood AnalyticsBrightLoopVanta SolutionsMeridian LabsArchway DigitalOakstone PartnersRivian TechPolaris MediaNexovaClearPath CRMDriftwood AnalyticsBrightLoopVanta SolutionsMeridian LabsArchway DigitalOakstone Partners

Frequently Asked Questions

Everything you need to know about email warming and Mailsim.

What is email warming?+
Email warming is the process of gradually building a positive sender reputation for a new or underused email address. By sending and receiving emails in a natural pattern over time, email providers learn to trust your domain and deliver your messages to the inbox instead of the spam folder.
Why do I need to warm up my email?+
New email accounts and domains have no sending history, so providers like Gmail and Outlook are more likely to flag your messages as spam. If you send cold outreach, newsletters, or transactional emails from an unwarmed account, your deliverability will suffer. Warming builds the trust signals that providers look for before placing your emails in the inbox.
How does Mailsim work?+
Once you connect your email account, Mailsim automatically sends emails from your address to our warming pool. Pool accounts then open, read, star, and reply to your messages — mimicking real human engagement. This generates positive signals that email providers use to evaluate your sender reputation. Volume starts low and gradually increases to avoid triggering spam filters.
How long does it take to see results?+
Most users see noticeable improvements in inbox placement within 2 to 3 weeks. Full reputation building typically takes 4 to 6 weeks depending on your domain age, sending volume, and starting reputation. Mailsim's dashboard lets you track your progress in real time.
Which email providers do you support?+
Mailsim supports Gmail, Google Workspace, Microsoft Outlook, Exchange Online, Yahoo, Zoho, and any provider that supports SMTP/IMAP. We also work with transactional email services like SendGrid, Mailgun, and AWS SES.
What is a Custom Template Test?+
Custom Template Tests let you send your actual email content — the exact template you plan to use in campaigns — to our test mailboxes. We then show you whether it landed in the inbox or spam, along with full authentication analysis (SPF, DKIM, DMARC), spam confidence scores, and blacklist checks. It's like a dress rehearsal before your real send.
Will warming trigger spam filters or get my account flagged?+
No. Mailsim uses gradual ramp-up controls that start with very low daily volumes and increase slowly over time. This mimics natural email behavior, which is exactly what providers expect. The engagement from our pool (opens, replies, stars) further reinforces positive signals.
Can I cancel anytime?+
Yes. All Mailsim subscriptions are month-to-month with no long-term contracts. You can cancel from the billing page at any time and your subscription will remain active until the end of your current billing period.
Is my email data secure?+
Absolutely. All email credentials are encrypted at rest using AES-256-GCM encryption. OAuth connections never expose your password. We do not read, store, or share the content of your personal or business emails — warming emails are generated by our system and are the only messages we interact with.
Do all plans include the same features?+
Yes. Every Mailsim plan includes automated warming, deliverability testing, blacklist monitoring, full header analysis, reputation tracking, and gradual ramp-up controls. There is no feature gating — the only difference between plans is the number of email accounts and daily volume limits.
Do you offer a free trial?+
Mailsim starts building inbox placement and sender reputation as soon as you connect an inbox. While we don't offer a traditional free trial, your email warmup begins immediately and is designed for long-term email deliverability rather than short tests.
Can I change my plan later?+
Yes. You can upgrade, downgrade, or add more inboxes at any time as your email warmup needs evolve.
When will I see results from email warmup?+
Most users see early improvements within the first few days/weeks, such as fewer emails landing in the spam folder. Stronger inbox placement and stable sender reputation typically build over 2 to 4 weeks of continuous email warmup.
Is Mailsim safe for my domain?+
Yes. Mailsim is designed to warm up email accounts gradually and safely. The inbox warmup process reduces domain spam risks and protects your sender reputation by mimicking natural email behavior.
Do you support Gmail, Google Workspace, and Microsoft 365?+
Yes. Mailsim supports major email providers, including Google Workspace / Gmail and Microsoft 365 / Outlook, as well as other SMTP-based platforms.
Can you warm up multiple domains?+
Yes. You can warm up inboxes across multiple domains, which is ideal if you separate outreach by brand, team, or risk level to better control email deliverability.
What happens if I want to add more inboxes mid-month?+
You can add inboxes instantly and scale your email warmup service at any time. There's no need to wait for a billing cycle reset.
Do you offer onboarding or setup help?+
Yes. Our support team can help you connect inboxes, configure warmup Gmail accounts, and apply best practices to avoid spam filters and improve inbox placement quickly.
Do you offer refunds?+
If something isn't working as expected, contact our support team. We'll review your setup, identify issues affecting email deliverability, and help you fix them.
Is email warmup enough to fix deliverability issues?+
Email warmup is a critical foundation, but the best results come from combining it with proper DNS setup, list hygiene, and smart sending patterns. Mailsim helps you with the highest-impact actions to avoid the spam folder and improve long-term inbox placement.

Ready to hit the inbox?

Join Mailsim today and start building your sender reputation. No contracts, no commitments, no hidden fees.

Get Started Now