Warmy.io: our review of this email warm-up tool

Most people looking for a warm-up tool have the same reflex: “my emails are going to spam, I’m going to warm up my inboxes.” And most of the articles on Warmy.io answer them with a list of features and a “it’s very good, 4 stars”. But that’s not what this is really about.

Warm-up alone won’t solve misconfigured DNS records, a prospect list full of invalid addresses, or overly commercial content. If your deliverability is catastrophic, Warmy can help, but it’s no substitute for a thorough audit. What really sets Warmy apart from its competitors is that it understands this. Behind the warm-up tool lies a complete infrastructure for monitoring email deliverability: blacklists, domain reputation, DNS analysis, performance by provider…

This makes Warmy.io one of the most advanced tools in its category. But, on the downside, it’s also the most expensive…with an opaque pricing model that can quickly become prohibitively expensive if you don’t know exactly why you need it. Read our full review of Warmy.io.

Our opinion about Warmy.io in a nutshell

What exactly is Warmy.io?

Warmy.io is a specialized email deliverability platform founded in Tel Aviv in 2020 by Daniel Shnaider. The story of its creation is fairly representative of a certain type of SaaS tool: Shnaider ran several companies, one of which relied heavily on cold email to acquire customers.

Its teams came up against a deliverability wall (opening rates plummeting, emails falling into spam traps). The software solution developed in-house to solve the problem was finally commercialized: Warmy.

Today, Warmy.io boasts over 35,000 customers and 650,000 domains whose deliverability has been improved. The tool belongs to AnyBiz LTD, which also publishes AnyBiz.io, an outbound IA prospecting platform (see our full review of AnyBiz.io). The relationship between the two products is symbiotic: AnyBiz generates the campaigns, Warmy ensures that the emails reach their destination. This is quite a clever vertical integration in the SalesTech market.

Warmy.io’s key features

Adeline AI: the warm-up engine

The classic email warm-up is based on a simple logic: send progressively more and more emails to “accustom” suppliers to your domain. The problem is that Google and Microsoft algorithms have learned to recognize these regular, predictable increments…and penalize them.

Warmy has developed a proprietary AI called “Adeline” to break out of this pattern. Adeline continuously analyzes the metadata generated by the entire network of boxes connected to Warmy (response speed, reading time, deletion, bookmarking) and makes up to 20 million automated decisions a day to calibrate the behavior of each individual box.

The underlying network is made up of real mailboxes (1 million+ accounts, according to Warmy anyway), not bots or automated scripts. These accounts send each other emails, read them, remove them from spam, reply to them. To email providers, it looks like normal human activity, because it is, at scale.

Another highlight is its crowd-learning capability. If Microsoft modifies its filtering rules for a sub-group of users, Adeline detects the signal and adapts the heating strategy for the entire network. It’s this real-time reactivity that sets Warmy apart from a simple dispatch scheduler.

Semantic heating by sector

This is the feature you won’t find in low-cost competitors, and probably the main reason for choosing Warmy over an alternative half the price.

In 2026, ESPs (e-mail service providers) will no longer simply count the number of e-mails sent. They analyze the semantic content of exchanges to categorize a domain’s legitimacy. A domain that regularly exchanges terms related to legitimate finance is treated differently from a domain whose emails talk about “unique opportunity” and “click now”.

Warmy lets you define the thematic sector of your warm-up: cybersecurity, real estate, SaaS, finance, healthcare, e-commerce…

The tool then generates automated exchanges in your industry’s professional vocabulary, in over 30 languages.

The most striking example is that of cybersecurity: a legitimate email from a company in the sector contains terms such as “phishing”, “vulnerability”, “threat” and “firewall”. To a conventional spam filter, this lexical density is immediately suspect.

By training your domain to exchange this vocabulary naturally with real boxes that answer and move your emails out of spam, Warmy “educates” providers’ algorithms to recognize your domain as a legitimate sender of this type of content.

“Warmup with Clicks

An open or a reply is good. A click on a link in the email is even better for ESP algorithms, which interpret it as a strong signal of genuine interest.

Warmy has developed a feature that goes so far as to simulate this behavior: network accounts open emails, click on embedded links, and browse briefly. A dedicated dashboard tracks five precise metrics at domain level and at the level of each individual box. It’s an extra layer of trust signals that few tools offer at this level of sophistication.

The deliverability dashboard and continuous monitoring

This is where Warmy really moves beyond being a “simple warm-up tool” to become a true email health platform.

The Domain Health Hub aggregates data on several critical dimensions in real time:

• Inbox / spam / promotions placement by provider (Gmail, Outlook, Yahoo)
• Domain and IP address reputation
• Presence on worldwide blacklists
• Validity of DNS records: SPF, DKIM, DMARC
• Google Postmaster Tools integration (official Google reputation in real time)

The difference with tools like MailReach is that Warmy doesn’t make “photographs” on demand, it continuously monitors in the background and alerts you if a problem emerges even before your campaigns suffer.

The “Template Performance Dashboard” is also very useful in practice: it lets you test whether an email template performs differently on Gmail vs. Outlook, and identify HTML formatting or signature problems before burning a list of qualified prospects.

The suite of free tools

Warmy provides a series of tools that are accessible without subscription, and which are useful in their own right:

• SPF Generator and DMARC tools: generate and verify your DNS authentication records
• Email Template Checker (Chrome extension): analyzes text/image ratio and HTML structure to identify filter triggers
• Signature Builder: create a professional email signature in line with best practice
• Deliverability Test (Seed List): sends a test email to control boxes and gives you an immediate report on inbox/spam/promotion placement.
• Cold email sequence builder

These tools are a good entry point for teams wishing to diagnose their deliverability without committing to a subscription. And they clearly underpin Warmy’s positioning as a deliverability authority.

Warmy.io prices: how much does it really cost?

This is the most uncomfortable part of this article…

Warmy does not publish its prices on its pricing page. Three plans are displayed: B2B Sender, B2C Sender and Custom. For each, the only option offered is to “book a demo”. This sends out a clear signal: the tool is expensive, and sales are made on the basis of a sales call to adjust the offer on a case-by-case basis.

What we know from external review data and specialized forums (Reddit):

What we like (and don’t like)

Warmy.io vs. the alternatives: which to choose?

The email warm-up market changed radically between 2024 and 2026. On the one hand, specialized tools like Warmy or MailReach, expensive but technically advanced. On the other, all-in-one platforms like Instantly or Smartlead, which integrate warm-up free of charge into their outreach subscription. And in between, unlimited fixed-price tools (TrulyInbox, Mailivery) that split the difference.

A word about all-in-one platforms (Instantly, Smartlead)

The major disruption of the last two years has been the emergence of platforms like Instantly or Smartlead, which offer both outreach and warm-up for a single monthly fee with unlimited inboxes.

That said, the warm-up integrated into these platforms is rudimentary. It does the basic job, but doesn’t offer advanced monitoring, semantic warming or real-time visibility of reputation variations.

Some users even report that Instantly’s free warm-up can, in borderline cases, degrade the reputation of a newly acquired domain through lack of algorithmic sophistication. Warmy then acts as a paid but reliable technical insurance policy for the teams using these tools.

Customer reviews: what users really say

Ratings on review platforms are among the highest in the category:

The points of satisfaction that consistently come up: the tangible improvement in inbox placement rates in just a few weeks (+22% on average according to Warmy), the quality of technical support, and the ease of getting started. The tool delivers on its “set-it and let-it-run” promise – once configured, it runs autonomously.

The criticisms are predictable and consistent with our analysis: the per-inbox model is seen as a “tax on growth” on Reddit, and some more advanced users feel that seed list testing would deserve more B2B professional boxes to be truly representative.

Our verdict: who is Warmy.io really for?

Warmy.io is for you if :

• You manage several domains for clients (lead gen agency, sales agency). That’s what Agency plans are for
• You operate in a semantically sensitive sector: finance, healthcare, cybersecurity, legal, HR (semantic warm-up is a must)
• You have a blacklisted domain or a damaged reputation to rebuild (Warmy is the reference tool for this).
• You want a complete diagnosis of your deliverability, not just a basic warm-up.
• Your email ROI is clearly quantifiable and justifies a premium infrastructure
• You send large volumes (10,000+ emails/month) where deliverability is a direct business issue

Skip it if :

• You have 1-2 mailboxes and occasional campaigns. Instantly’s integrated warm-up or a fixed-price tool will do the job.
• You have not yet configured SPF, DKIM and DMARC
• You’re looking for an outreach tool (let’s repeat: Warmy does not replace a cold email tool)
• Your marketing budget is limited and you need a scalable, fixed-price solution
• Your teams are mainly on Microsoft 365 / Outlook

Warmy.io is without doubt the most technically advanced email deliverability tool in its category. The semantic heating, continuous monitoring, Adeline AI and depth of the dashboard are solid arguments for teams involved in high-stakes B2B email. The point of vigilance remains its pricing model: per-inbox, opaque, and which penalizes growing teams.

If you know exactly why you need a premium deliverability infrastructure, Warmy is the right choice. If you’re just looking to avoid spam with a few mailboxes, take a look at the cheaper alternatives first.