Software Alternatives & Reviews

OpenSMTPD VS Warmup Inbox

Compare OpenSMTPD VS Warmup Inbox and see what are their differences

OpenSMTPD logo OpenSMTPD

OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with...

Warmup Inbox logo Warmup Inbox

Warmup Inbox is a tool that automates the process of warming up your email inboxes, raising your sender reputation and inbox health automatically.
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OpenSMTPD Landing Page
OpenSMTPD Landing Page
Warmup Inbox Landing Page
Warmup Inbox Landing Page

The process of preparing an email address for general use or email outreach is commonly referred to as “Warming Up” an inbox, where you take a number of steps to ensure that an email address does not become deactivated, blacklisted, or automatically marked as spam when it begins to send outgoing messages to other recipients.

Warming Up an email inbox essentially is recreating the way a typical person will use an email address. Just by using your email address normally, you are ‘warming up’ your inbox by sending outgoing mail to other existing users. When you are reading your emails, starring/favoriting certain messages, and engaging in email threads with multiple other email addresses, you are building up your domain reputation in a way that shows that your account is being controlled by a real human being and is not being used to send out unsolicited emails that are trying to mislead/scam/defraud any other real people using their email inbox.

OpenSMTPD details

SMTP Server MTA Email
Pricing URL-
Details $-

Warmup Inbox details

Email Warm Up Cold Outreach Startup Marketing Email Marketing Technology Cold Email Email Tools Marketing Tools Bootstrap Tools
Pricing URL Official Warmup Inbox Pricing  
Details $paid Free Trial $12.0 / Monthly (Per inbox, per month.)
Google Workplace Microsoft 365 Zoho Outlook Amazon Web Services Mailgun Sendgrid SendPost SMTP Yahoo GMail

OpenSMTPD features and specs

Not specified yet

Warmup Inbox features and specs

Automatically warms up domain to be ready for cold email Automatically warms up domain to be ready for cold email
Improve Email Deliverability Improve Email Deliverability
Improve Domain Reputation Improves Domain Reputation
Improve IP Reputation Improves IP Reputation
Restore Bad Inboxes Restores Bad Inboxes
Gmail Integration Gmail Inbox Warmup
Outlook Email Integration Outlook Inbox Warmup

OpenSMTPD videos

DAY[0] Episode #31 - kr00k, GhostCat, and more issues from NordVPN, Samsung, OpenSMTPd

Warmup Inbox videos

How to Setup Warmup Inbox | Email Inbox Warmup for Cold Email | Lemwarm Alternative

Category Popularity

0-100% (relative to OpenSMTPD and Warmup Inbox)


These are some of the external sources and on-site user reviews we've used to compare OpenSMTPD and Warmup Inbox

OpenSMTPD Reviews

We have no reviews of OpenSMTPD yet.
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Warmup Inbox Reviews

23 Best Cold Email WarmUp Tools in 2022 (Free + Paid)
And now you got the options to choose an inbox type now here your real deal starts.Once you sign up, Warmup Inbox floods your inbox with good emails. The tool automatically builds and sends smart dynamic content within every email.connects to Gmail, Outlook, SMTP or any other inbox, domain tracking &
Top 10 of the Best Email Warm Up tools in 2022
Warmup Inbox is rated 2.9 / 5 on average, out of 9 reviews on G2 and Capterra. Note: This low rating doesn’t necessarily reflect the Warmup Inbox’s actual value. Indeed, since they have only 9 ratings, a few bad reviews were enough to downgrade their overall note.
7 Best Cold Email Warm-up Software
Warmup Inbox shows real-time inbox health scores. This score is calculated based on the DNS settings, security protocols, blacklists status, and ISP reputation. Hence, you can keep track of the progress.

Social recommendations and mentions

Based on our record, Warmup Inbox should be more popular than OpenSMTPD. It has been mentiond 3 times since March 2021. We are tracking product recommendations and mentions on Reddit, HackerNews and some other platforms. They can help you identify which product is more popular and what people think of it.

OpenSMTPD mentions (1)

Warmup Inbox mentions (3)

  • Did anyone else's notice Gmass warmup fall off a cliff?
    I'm also using with the same email address and see no problems. - Source: Reddit / 11 days ago
  • Please help me with an email account
    Join this warmup tool it is 9 buscks a month and will improve your domain at least for other providers, I dont think it will help with outlook tho. im one week sending and receiving about 50 emails a day. - Source: Reddit / 10 months ago
  • Help with email issue!
    You can also use a warm up service like for 9 bucks a month will improve your domain reputation. - Source: Reddit / 10 months ago

What are some alternatives?

When comparing OpenSMTPD and Warmup Inbox, you can also consider the following products

Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail. - Warm up your cold email inbox, and never land in spam anymore!

sSMTP - sSMTP is a simple MTA to deliver mail from a computer to a mail server. - The #1 email warming service to improve your deliverability by generating realistic and meaningful engagement to your emails. Easy-to-use solution to help you land in the main inbox instead of the spam folder.

Sendmail - Sendmail is a general purpose internetwork email routing facility that supports many kinds of...

Mailwarm - The email warm-up tool.

User reviews

Share your experience with using OpenSMTPD and Warmup Inbox. For example, how are they different and which one is better?
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