Best Warmup Tools in 2024: Critical Analysis

Ask ten email marketers and you’ll get ten different opinions on email warmup tools. Some swear by them as the “best thing invented to avoid spam”. Others claim they’re the reason for landing in spam instead of the main inbox.

Some email warmup services can improve your reputation with ESPs, while others only temporarily increase email sending volume for new inboxes. 

Our Product Team spent hours analyzing existing email warmup solutions and their shortcomings. But why keep this information private, right? Below is our take on the popular email warmup tools for their features, efficacy, and pricing to provide a critical assessment.

7 Best Email Warmup Tools: Critical Review

⚠️ Don’t confuse warmup tools with email deliverability platforms. 

An email warmup service only attempts to improve your IP and/or domain reputation without addressing other elements of email deliverability: infrastructure configurations, content quality, and adherence to other best practices. 

Teams at our lead gen agency, Belkins, were frustrated that we needed several tools to ensure the above. So there came Folderly — a one-stop-shop email deliverability platform. 

Folderly leverages real-time inbox placement data, IP and domain reputation, and DNS settings to build a custom deliverability score for each inbox. With it, you can know exactly where you stand and how to do better using personalized alerts and best practices, from our success team. 

Incorrect DMARC settings? We’ll tell you how to fix it. Spam words in your latest templates? Fix that in our Grammarly-style editor.  Our tool also programmatically monitors your IP and domain reputation and adjusts inbox warmup scenarios in the background — no extra fiddling on your part is required.

That said, if you’re looking for a simpler email domain warmup tool, here are most popular options. 

Warmy.io

Warmy is arguably the best email warmup tool in terms of analytics. The dashboard offers a daily warmup activity overview, including inbox placement data. You can review historic trends for up to a year. For more granular data, you can run an inbox placement test (capped by account tier) for benchmarks across ESPs. However, Warmy only segments emails as inbox or spam, so you can’t tell if your emails end up in ‘social’ or ‘promotion’ folders on Gmail.

The email warmup service includes 3 warmup modes: Slow, medium, and fast, each with a custom daily email cap. On higher account plans, you can select email warmup topics, but you can’t adjust parameters like daily ramp-up, email timing, or reply rate. Warmy doesn’t auto-reply to emails during the warmup process.

Read our full review of Warnmy (featuring a better alternative). 

Key features

• Progressive warmup of your email domain and IP address with 3 inbox ‘temperature’ settings.

• Run checks for word count, reading time, and spam words on your template.

• Automatically archives all the warm-up messages to avoid flooding your inbox. 

Weaknesses: 

• Warmy’s warmup scenario doesn’t include replying to emails. The algorithm only opens, reads, and marks emails as important.

• Capped number of DNS settings tests and inbox placement tests per account.

• Only classifies emails as main inbox or spam, so you can’t tell if you’re getting stuck in promotion folders.

Pricing: From $49 per mailbox, capped at 100 daily warmup emails.

Lemwarm

Lemwarm is a spin-off email warmup tool from Lemlist, a sales enablement platform. It runs a ‘black box style’ for warmup, automatically determining email sending rates based on your domain age and sender reputation. You can add characteristics like industry, country, and email type for personalization.

For each connected inbox, you get a proprietary deliverability score, based on the inbox placement data. The platform also provides contextual tips on how to further increase your deliverability rates. By default, the platform sends generic email texts (of mixed quality), but you can use your own email template on a Pro plan. Unlike Warmy and Warmup Inbox, Lemwarm doesn’t have an in-built template checker. So you may want to experiment with several options. 

Read our full review of Lemwarm (featuring a better alternative). 

Key features: 

• Convenient reporting dashboard with warmup activity, deliverability scores, and inbox placement rates (main, promo, spam).

• Unified interface to manage warmup activity across multiple inboxes, adjust ramp-up rates, start and stop active campaigns.

• Smart Cluster feature on the Pro account tailors email content to your industry and target audience. 

Weaknesses: 

• Performs warmup only on domain level, but doesn’t perform IP-level warmup. 

• Doesn’t support connection via SMTP relays and cannot be used with ESPs like Sengrid, Mailgun, Sendinblue, and AmazonSES among others. 

• No DNS record configuration tools or email infrastructure monitoring is available.

Pricing: From $29/month per inbox. 

Warmup Inbox

Warmup Inbox runs a network of 15,000+ active inboxes. It’s more affordable than other email warmup tools but limits the total number of warmup emails to 75 per day. On the cheapest plan, you cannot customize warmup settings, apart from adjusting the reply rate.  Higher account tiers allow warmup topic customization and give the ability to prioritize warmup for a specific ESP. 

The company’s network mostly has Google Workspace inboxes and fewer Outlook and accounts with other ESPs, so some users complained that their inbox wasn’t warmed up on the cheapest plans. The company also doesn’t proactively disclose that certain connectors (e.g., SendGrid) require a more expensive plan.

Key features

• Automated warmup with adjustable reply rates, topics, and other settings, based on the current plan.

• Monitors SPF & DKIM settings and alerts about potential misconfiguration, but doesn’t have SPF & DKIM generators.

• Free inbox placement test and spam word checker tools. 

Weaknesses

• The app sometimes glitches and stops warmup for no reason without alerting the user.  

• If you have to change your SMTP settings, such as a password, your analytics data is lost, and you have to create a new account with them.

• Limited historical analytics. You can only view deliverability rates for the past Depending on the date, you can see 30 days of data, at other points, one day. There is no way to view a rolling period of 30 days.
  

Pricing: From $19/mo per inbox, capped at 75 warmup emails per day. 

Instantly.ai

Instantly touts itself as an AI-powered email warmup software, though its algorithm doesn’t differ much from other platforms. 

On the cheapest plan, Instantly only sends warmup emails on a set schedule, but doesn’t emulate any activity like removing from spam, opens, and replies, which makes it mildly efficient. If you want to access an extra warmup setting, you’ll have to upgrade to a more expensive $97/mo plan. 

Unlike other email warmup tools on this list, Instantly doesn’t have pre-programmed warmup scenarios. You can set a custom daily email send, reply, or spam removal rate. This may be a pro for experienced email marketers, but novice users may easily overdo it and damage their reputation. 

Read our full review of Instantly (featuring a better alternative). 

Key features:

• Cold email Campaign Builder and team interface for lead tracking and management. 

• Connected an unlimited number of inboxes for unlimited daily warmup activity, using pooled inboxes.

• Automatic inbox rotation for cold email sending, based on the reputation and sending volumes. 

Weaknesses: 

• Performs warmup using a pool of user email addresses (not premium inboxes with established reputation), which is less effective. 

• Doesn’t provide inbox placement data. You only see the total number of delivered (non-bounced) emails, rather than inbox vs spam placements. 

• Has ‘open tracking’ enabled by default for all emails. Tracking pixels can negatively affect deliverability. 
  

Pricing: From $30/mo per month for unlimited email accounts, capped at 5,000 emails per month. 

Mailwarm

Mailwarm is another popular warmup email platform with a 2-minute setup. Depending on the plan, you can send 50, 200, or 500 warmup emails per day. Their pool network is smaller, featuring only 5,000 inboxes (vs 10K+ among other providers). Apart from the daily volume, there aren’t other parameters you can customize. You can’t select topics or provide your own templates — Mailwarm auto-generates all content.

Compared to other ​​email warmup services, Mailwarm’s analytics is quite limited. You can track daily activity for all connected inboxes, but that’s all — no inbox placement data or health scores.

Overall, it’s a simple tool that does one thing: Increases sending volumes per inbox. But the low quality of email content and limited analytics are deal-breakers for users. Read our full review of Mailwarm  (featuring a better alternative). 

Key features

• Daily pre-programmed warmup activity, capped at 50/200/500 emails. 

• Dashboard with daily activity activity for all inboxes 

• Connects with all major ESPs via custom SMTP.  

Weaknesses: 

• Doesn’t provide any tools for SPF, DKIM, DMARC, and BIMI configuration. 

• Doesn’t provide data on inbox placement rates or deliverability scores per inbox. Analytics is limited to daily sending activity reports.

• No recommended warmup scenarios or options to customize settings beyond the total number of daily emails.

Pricing: From $69/mo for one inbox, capped at 50 daily warmup emails.

TrulyInbox

TrulyInbox is the cheapest email warmup tool on the list, with plans starting at $12/month per inbox. The low price? Similar to Instantly, TrulyInbox relies on user mailboxes to perform warmup. So the selection of ESPs and the reputation of each inbox can vary a lot. Each email gets opened, replied to, and marked as starred by the platform’s algorithm. You then need to set a custom filter to remove warmup emails from your main inbox.

The platform has a standard warmup scenario with slight adjustments on wait times depending on the ESP. You can’t change default settings, apart from increasing daily sending volumes or ramp-up configs if you’re on a higher plan. 

Analytics includes a deliverability rate score for each inbox, based on the inbox placement data (main vs spam). But it’s not clear how TrulyInbox classifies emails that landed in “promo” or “social” folders. 

Key features

• Pre-programmed warmup scenarios with human-like interactions to increase sender reputation. 

• Analytics dashboards with daily warmup activity and inbox placement data. 

• Easy integration with Gmail, Office 365, Outlook.com, Yahoo Mail, Zoho, and GoDaddy.

Weaknesses: 

• The email pool consists of user inboxes of different age and reputation, which can undermine the warmup efficiency.

• Doesn’t support ESPs that use a custom SMTP/IMAP hostname or use any custom server settings.

• Doesn’t allow using custom email templates and doesn’t provide tools for validating email content for spam triggers. 

Pricing: From $12 per 5 connected inboxes, capped at 50 daily emails per account. 

Warmbox

Warmbox is another ultra-affordable email warmup tool. Unlike TrulyInbox and Instantly, Warmbox says it operates a private network of 10K inboxes across 100 countries with a good reputation. However, some users complained that the network mostly has free Gmail accounts. 

You can choose among three pre-suggested warmup scenarios or create a custom one by adjusting email timing, volume, and reply rates among other parameters. Unlike Warmy and Lemwarm, Warmbox doesn’t let you choose specific warmup topics or use your own templates. Instead, the tool uses premade texts and some GPT-4 help to create emails and replies.

You get daily reports on warmup activity, plus a custom deliverability score on a 0 to 100 scale. The score is based on a combination of signals from IP  blacklists and spam traps, which Warmbox tracks. But doesn’t account for inbox placement data – Warmbox doesn’t report this.

Read our full review of Warmbox (featuring a better alternative). 

Key features

• Three pre-made warmup recipes and an advanced option to create a tailored scenario. 

• Integrated blacklist checker to monitor your reputation. 

• Integrates with all major ESPs via SMTP.

Weaknesses: 

• Doesn’t provide inbox placement data to track the percentage of emails that land in spam, making it hard to understand the tool's efficacy. 

• Doesn’t let you validate specific email templates. The supplied content can be hit or miss. 

• Doesn’t provide alerts about possible infrastructure configuration issues. 

Pricing: From $15/mo for inbox warmup, capped at 50 daily emails. 

Why Consider an Email Deliverability Platform, Instead of a Warmup Tool 

Email warmup and email deliverability aren’t the same thing. 

Email warmup tools only increase sending limits per connected inbox. This is great if you want to go past the ESP-set caps to scale your outreach campaigns. 

But email deliverability is a bit more complex than that. To consistently land in the main user inbox, you also need to follow other email deliverability best practices: Maintain correct delivery infrastructure configurations, use proper email formatting, maintain high list quality, and monitor your IP and domain reputation. 

Folderly’s pricing may not be as affordable as your regular email warmup tools, but we also do much more than temporarily increase sending volumes per inbox. With the help of our platform, users have recovered from domain blacklisting, stopped landing in the promo folder, and tripled their revenue from email. 

Read more case studies and interviews with our clients. Or better yet — try our product for free for 7 days. 😉