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Warmupinbox: Warm your inbox for next to nothing

Sales Tools

Warmupinbox: Warm your inbox for next to nothing

Email prospecting can present a challenge, particularly ensuring that your messages reach the intended recipients' inboxes. Even the most thoughtfully crafted and compelling message is ineffective if it goes unnoticed in a spam folder. Warmupinbox solves this problem by methodically increasing the volume of your email sending over time.

Michel Lieben

MAR 17 2026

Warmupinbox: Warm your inbox for next to nothing

Email prospecting can present a challenge, particularly in ensuring that your messages reach the intended recipients' inboxes. Even the most thoughtfully crafted and compelling message is ineffective if it goes unnoticed in a spam folder. Warmupinbox solves this problem by methodically increasing the volume of your email sending over time.This approach improves deliverability, preserves the reputation of the sender, and most importantly, guarantees that the emails are received and read by the prospects.

WHAT IS WARMUPINBOX?

Warmupinbox is an innovative software that helps businesses enhance the effectiveness of their email communications by improving email deliverability. When a new email account or domain is established, it may take time to establish credibility with Internet Service Providers (ISPs). During this period, emails from the new account may be misconstrued as spam or land in the recipient's junk folder.

To overcome this challenge, Warmupinbox simulates interactions between your inbox and other inboxes, ensuring that your emails land in the primary inbox of the recipient. It does this by removing flagged emails from the spam folder and marking the message as safe, which sends a positive signal to email platforms, increasing the chances of your emails being delivered to the primary inbox in the future.

By improving email deliverability, Warmupinbox can aid in increasing reply and conversion rates, which ultimately translate to increased revenue

Website: https://www.warmupinbox.com

PRICING

Warmupinbox offers a subscription-based pricing model starting at $12/month, which is determined by the number of email accounts and warmup volume. The cost per account decreases as more inboxes are added.

MAIN FEATURES

Warmupinbox's key features include:

Gradual warming of multiple email accounts
Evaluation of message delivery success
Complete automation of the warm-up process
Capability to send up to 500 messages per day
Compatibility with most Internet Service Providers.

RATINGS

G2: 4.7/5 (22 reviews)

Capterra: 4.6/5 (7 reviews)

ALTERNATIVES

Warmupinbox is a popular email warming software, but you may want to look at other options. There are tools such as:

Lemlist and Instantly allow you to automate your sales process and gradually increase the number of emails you send over time through their built-in warmup capabilities.
Warmbox is another option with more features at a similar price.
My personal favourite is Mailreach, which has a lot of features and is popular among sales professionals.

The best option for you will depend on your needs and budget. It's not worth spending too much time trying to find the perfect one, as most will work well.

DISCOVER MORE TOOLS

Looking for the best sales prospecting tools? Check out coldiq.com/tools for a comprehensive list of over 200 tools organized by category. No matter what your prospecting needs are, you're sure to find a tool that meets them.

CONCLUSION

Warmupinbox is an excellent email warmup solution that improves deliverability and protects the sender's reputation. If your main concern is ensuring emails land in your recipient’s primary inbox, it's worth considering.

For more affordable and large-volume solutions, Instantly is a good option with a built-in warmup feature and sales automation.

Personally, I use Mailreach for my primary email addresses and Instantly for additional inboxes when scaling campaigns.

Ultimately, the best solution depends on your needs and budget.

‍

Michel Lieben

Founder, CEO

Michel Lieben is the Founder & CEO of ColdIQ, a B2B sales prospecting agency trusted by 100+ organizations. He’s launched hundreds of outbound campaigns, mastered tools like Clay and Lemlist, and shares sharp, actionable insights on scaling sales with AI, automation, and strategy.

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FAQ

What types of email accounts can Warmupinbox work with?

Warmupinbox supports almost all major email providers, including Gmail, Outlook, and custom domains. It handles both new and existing accounts, adjusting the warmup pace based on account history and reputation to improve deliverability effectively.

How does Warmupinbox ensure emails don't get flagged as spam?

It simulates natural email interactions like opens and replies within its network, which signals to ISPs that your emails are wanted. This activity, combined with removing emails from spam folders, gradually builds the sender reputation without manual effort.

Can Warmupinbox help if my email domain is brand new?

Yes, Warmupinbox is specifically designed to help brand new domains gain trust with ISPs by starting with low sending volumes and increasing them progressively. This approach reduces the risk of being blacklisted or filtered out as spam early on.

What happens if I stop using Warmupinbox after warming up?

If you stop warmup activities suddenly, your sender reputation might decline over time, especially with low email volumes. It is recommended to maintain consistent sending patterns even after warmup to preserve deliverability improvements.

Is it possible to customize the warmup schedule for different inboxes?

Warmupinbox allows some flexibility in scheduling warmup sessions based on your needs, but it primarily automates the process to keep sending gradual and consistent. This minimizes manual adjustments while ensuring steady reputation growth across multiple inboxes.

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