Software Alternatives, Accelerators & Startups

Clearbit VS Mailwarm

Compare Clearbit VS Mailwarm and see what are their differences

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Clearbit logo Clearbit

Clearbit provides Business Intelligence APIs

Mailwarm logo Mailwarm

Email warmup tool to avoid spam folder, since 2020 - Backed by Email Deliverability Experts
  • Clearbit Landing page
    Landing page //
    2023-10-06
  • Mailwarm best email warmup tool
    best email warmup tool //
    2026-02-04
  • Mailwarm best email warmup tool - spam score
    best email warmup tool - spam score //
    2026-02-04
  • Mailwarm See Why Teams Love Mailwarm
    See Why Teams Love Mailwarm //
    2026-02-12
  • Mailwarm Activity of email interactions
    Activity of email interactions //
    2026-02-12
  • Mailwarm live spam score monitoring
    live spam score monitoring //
    2026-02-12
  • Mailwarm Deliverability Analytics
    Deliverability Analytics //
    2026-02-12

Mailwarm is an automated email warmup and deliverability platform designed to help businesses keep their emails out of spam folders and consistently reach the inbox.

Since 2020, Mailwarm has helped founders, sales teams, marketers, and agencies improve email deliverability, build strong sender reputation, and scale cold email outreach safely. We focus on the real fundamentals of deliverability: trust, consistency, and genuine engagement.

Mailwarm automatically warms up new domains, inboxes, and SMTP servers by generating natural interactions between real email accounts. This process protects your reputation, prevents spam filtering, and improves inbox placement across major providers including Gmail, Outlook, Microsoft 365, and Yahoo.

Key Features: - Automated email warmup for Gmail, Outlook, and Microsoft 365 - Multi-provider warmup for realistic sender reputation building - Spam score tracking to measure inbox vs spam performance - Bounce prevention and verification systems - SMTP, domain, and mailbox warmup - Easy one-click Outlook & Office365 connection - Guided SMTP setup and deliverability monitoring - Stable warmup with auto-recovery from connection issues - Team and agency management with flexible plans

Email warmup is not a hack, itโ€™s a process. Mailwarm was built to do it properly, using real engagement signals to help your emails earn long-term trust with mailbox providers.

Whether youโ€™re launching new outreach campaigns, onboarding new sales reps, or managing multiple client accounts, Mailwarm helps you send emails with confidence and achieve better inbox placement instead of landing in spam.

Mailwarm is not just an email warmup tool. Every plan includes an email deliverability expert who works with you to set up your infrastructure, monitor your performance, and fix issues that impact your inbox placement. Most tools show you data. Mailwarm helps you improve results.

Clearbit

$ Details
-
Platforms
-
Release Date
-

Mailwarm

$ Details
paid $69.0 / Monthly ("Up to 50 emails/day", "1 account (1 SMTP)", "Chat support")
Platforms
GMail Outlook SMTP Zoho Web Yahoo Mail
Release Date
2020 December
Startup details
Country
France
City
Rouen
Founder(s)
Gonzague Hacher, Amine Benjelloun, Thami Benjelloun, Othman Katim
Employees
10 - 19

Clearbit features and specs

  • Extensive Data Coverage
    Clearbit offers comprehensive and up-to-date information on companies and individuals, making it a valuable tool for sales, marketing, and business intelligence.
  • Real-Time API
    The real-time API allows for the instant enrichment of data, enabling users to access detailed information without delays, which is useful for dynamic applications.
  • Seamless Integration
    Clearbit easily integrates with major CRM platforms, email marketing tools, and other software, facilitating its adoption into existing workflows.
  • Enrichment and Prospector Features
    Clearbit offers features like email enrichment and prospecting, helping businesses find and target the right contacts efficiently.
  • Quality of Data
    The data provided by Clearbit tends to be highly accurate, which is crucial for making informed business decisions and campaigns.
  • Enhanced Lead Identification
    The Weekly Visitor Report by Clearbit allows businesses to identify anonymous website visitors by providing detailed company data, which enhances lead generation efforts.
  • Comprehensive Data Insights
    The report provides in-depth information about visitors, such as company size, industry, and location, enabling more targeted marketing strategies.
  • Improved Sales Outreach
    With detailed visitor reports, sales teams can tailor their outreach strategies and prioritize leads based on the potential value and relevance of each visitor.
  • Easy Integration
    Clearbit's platform can be easily integrated with existing CRM systems, ensuring a seamless workflow for tracking and utilizing visitor data.
  • Comprehensive Data
    Clearbit Connect provides detailed information about contacts, including email addresses, company details, and social media profiles, making it easier for businesses to find and verify leads.
  • Ease of Use
    The extension integrates seamlessly with Gmail and G Suite, making it straightforward for users to gather information without leaving their email interface.
  • Time-Saving
    Clearbit Connect automates the process of finding contact information, reducing the time spent on manual search and allowing users to focus on outreach efforts.
  • Free Tier Availability
    A free version is available which allows users to access basic features without any initial cost, making it accessible for small businesses and startups.
  • Reliability
    Clearbit is known for providing accurate data, reducing the chances of bounced emails and improving overall outreach effectiveness.

Possible disadvantages of Clearbit

  • Cost
    Clearbit can be expensive, particularly for small businesses or startups with limited budgets. The pricing model may not be feasible for all organizations.
  • Data Privacy Concerns
    As Clearbit collects and provides detailed personal and corporate data, there may be concerns about privacy and compliance with data protection regulations.
  • Data Variability
    While the data is generally accurate, there can be occasional inconsistencies or outdated information which could affect decision-making.
  • Technical Integration Complexities
    Although Clearbit offers many integrations, setting them up and maintaining them can sometimes be complex and require technical expertise.
  • Dependency on Internet
    Using Clearbit's real-time API requires a stable internet connection, which could be a limitation in areas with poor connectivity.
  • Cost Considerations
    Clearbit's comprehensive data services can be expensive, especially for startups or small businesses with limited budgets.
  • Accuracy Limitations
    While Clearbit provides extensive data, the accuracy and timeliness of the information may sometimes be limited, potentially affecting decision-making.
  • Complexity in Setup
    For businesses without a dedicated IT team, the initial setup and integration of Clearbitโ€™s services can be complex and require technical expertise.
  • Limited Free Usage
    The free tier has limitations on the number of searches and data available, which may require users to upgrade to a paid plan for higher volume needs.
  • Privacy Concerns
    Some users may have concerns about the privacy of their data, as Clearbit collects and processes a significant amount of personal and company information.
  • Data Freshness
    While generally reliable, occasionally the provided data may not be up-to-date, leading to outdated contact information.
  • Integration Issues
    There may be occasional issues or bugs with the Gmail integration, causing some users to experience interruptions in their workflow.

Mailwarm features and specs

  • Automated Email Warmup
    Mailwarm automatically warms up inboxes, domains, and SMTP servers by generating natural interactions between real email accounts to build and protect sender reputation.
  • Multi-Provider Warmup
    Supports warmup across Gmail, Outlook, Microsoft 365, Yahoo, and other providers to create realistic engagement signals and improve overall inbox placement.
  • Spam Score Monitoring
    Provides a weekly spam score that shows how often your emails land in your spam versus inbox, helping you track deliverability progress with real data.
  • Bounce Prevention & Verification
    Built-in verification systems detect and deactivate invalid inboxes automatically to prevent bounces, one of the most harmful signals for email deliverability.
  • One-Click Outlook & Office365 Setup
    Connect Microsoft 365 and Outlook accounts instantly through the official Microsoft sign-in process without complex SMTP configuration.
  • Simplified SMTP Configuration
    Pre-configured SMTP settings for major providers with step-by-step guidance make it easy to connect and start warming up in minutes.
  • Deliverability Analytics
    Detailed reports help users monitor warmup progress, engagement trends, and overall email performance to understand and improve sender reputation.
  • Engagement Simulation
    Mailwarm engages with emails by marking them as important, replying, and removing them from spam, mimicking the actions of a real recipient and thereby boosting sender reputation.

Possible disadvantages of Mailwarm

  • Cost
    Mailwarm is a premium service, which may be expensive for small businesses or individual users with limited budgets.
  • Dependency on Third-Party Tool
    Relying on an external service like Mailwarm means users don't have full control over the warming process, and there might be risks related to data privacy and service reliability.
  • Learning Curve
    Although the platform is designed to be user-friendly, new users might still face a learning curve in understanding and fully utilizing all features and analytics provided.
  • Limited Customization
    Some users may find that Mailwarmโ€™s automation features lack the level of customization required for highly specific or complex email strategies.
  • No Instant Results
    The warming process is gradual and can take several weeks to show significant improvements in deliverability, which might not meet the needs of users looking for immediate results.

Analysis of Mailwarm

Overall verdict

  • Mailwarm is generally considered useful for businesses and individuals looking to improve their email deliverability rates. While there are positive reviews about its effectiveness in enhancing email reputation and ensuring better deliverability, the effectiveness may vary depending on individual use cases and how well the service is integrated with existing email strategies. It is most beneficial for users who have experienced issues with emails going to spam or have recently started using new email addresses for their campaigns.

Why this product is good

  • Mailwarm is a service designed to help increase the deliverability of emails by gradually warming up email addresses, particularly those used in cold email campaigns. It automates the process by sending emails from your account to its network of participants and receiving replies, which helps to build a positive reputation for new email addresses with email service providers. This can lead to better inbox placement and reduce the chances of emails being marked as spam, especially important for businesses engaged in outreach and marketing via email.

Recommended for

  • Businesses engaged in regular cold email outreach.
  • Startups launching new email campaigns.
  • Marketers looking to improve email deliverability.
  • Individuals and companies experiencing low open rates due to spam issues.

Clearbit videos

Clearbit - Reev & OTB | Outbound Reviews #6

More videos:

  • Review - The Weekly Visitor Report by Clearbit
  • Review - Clearbit Lead Enrichment Automations and Integrations (2019)
  • Review - E996 Clearbit CEO Alex MacCaw is creating god-mode for marketers, prioritizing profitability

Mailwarm videos

No Mailwarm videos yet. You could help us improve this page by suggesting one.

Add video

Category Popularity

0-100% (relative to Clearbit and Mailwarm)
Lead Generation
100 100%
0% 0
Email Marketing
0 0%
100% 100
Sales Tools
100 100%
0% 0
Email Warm Up
0 0%
100% 100

Questions & Answers

As answered by people managing Clearbit and Mailwarm.

What makes your product unique?

Mailwarm's answer:

Mailwarm is an email warmup and deliverability platform built by a Y Combinator and Station F startup.

Since 2020, weโ€™ve worked with many types of companies: SaaS startups, recruitment agencies, e-commerce brands, and sales teams; to help them improve inbox placement safely.

Mailwarm is unique because it offers: - Real multi-provider warmup (Gmail, Outlook, Microsoft 365, Yahoo)

  • Clear and real spam score tracking

  • Built-in bounce prevention

  • Easy setup and stable automation

Our focus is simple: help businesses keep emails out of spam and land in the inbox.

Why should a person choose your product over its competitors?

Mailwarm's answer:

Mailwarm delivers real, measurable results instead of risky shortcuts.

Users choose Mailwarm because it provides: - Automated email warmup that protects sender reputation

  • Multi-provider engagement for realistic signals

  • Spam score to track deliverability progress

  • One-click Outlook and Office365 connection

  • Reliable campaigns with auto-recovery

Itโ€™s an easy, transparent, and professional way to improve email deliverability.

How would you describe the primary audience of your product?

Mailwarm's answer:

Mailwarm is for anyone who depends on email outreach:

  • Sales teams sending cold emails

  • Founders and startups launching new domains

  • Marketing agencies

  • Recruiters and staffing firms

  • Growth and outbound teams

If inbox placement matters to your business, Mailwarm is built for you.

What's the story behind your product?

Mailwarm's answer:

Mailwarm started as a real problem we faced ourselves.

We were two founders working at Station F in Paris, the largest startup incubator in Europe, trying to sell our own products. Every time we launched outreach campaigns, our emails kept landing in spam.

To solve this, we built an internal email warmup system for our personal use. After deep research into email deliverability, we created a stronger, more reliable solution.

Other startups in the incubator quickly asked to use it too; so we turned it into a real product.

After launching publicly, Mailwarm became #1 Product of the Day on ProductHunt and was accepted into Y Combinator, the worldโ€™s most prestigious startup accelerator.

Since then, Mailwarm has grown into a trusted platform used by thousands of companies to improve inbox placement and email deliverability.

Which are the primary technologies used for building your product?

Mailwarm's answer:

Mailwarm is a secure cloud-based SaaS platform built on:

  • SMTP and IMAP email protocols

  • Advanced verification systems

  • Multi-provider infrastructure

  • Real-time analytics and monitoring

  • Reliable automation engines

These technologies ensure stable, continuous email warmup.

Who are some of the biggest customers of your product?

Mailwarm's answer:

As a Y Combinator and Station F startup, Mailwarm works with:

  • Tech startups and SaaS companies

  • Recruitment and staffing agencies

  • Real Estate Agencies

  • B2B marketing agencies

  • E-commerce brands

  • Sales and outbound teams

  • Freelancers and consultants

From France to global markets, hundreds of organizations trust Mailwarm to improve email deliverability and inbox placement.

User comments

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Reviews

These are some of the external sources and on-site user reviews we've used to compare Clearbit and Mailwarm

Clearbit Reviews

Top 13 ZoomInfo Alternatives
Clearbit is all about quality data. This solution is designed for smarter scoring, better routing, and more revenue. Clearbit automatically updates sales records with the accurate company and contact data.
Source: taskdrive.com

Mailwarm Reviews

  1. katewalker
    ยท Senior Digital Marketing Manager at Midland States Bank ยท
    Steady Improvement in Email Deliverability

    I decided to try Mailwarm after having consistent issues with my emails landing in spam folders. At the beginning, I wasnโ€™t fully sure what to expect, but the onboarding process was simple enough to get me started quickly. After running it for a while, I began to notice a steady improvement in my email deliverability. More of my messages started reaching the inbox instead of getting filtered out, which really helped with my outreach efforts. Overall, itโ€™s been a reliable experience. It may not be perfect, but it definitely does what itโ€™s supposed to do if you give it time.

    ๐Ÿ Competitors: Lemwarm by Lemlist
  2. John Fitzpatrick
    ยท CEO at Dublin's FM104 ยท
    Helped My Emails Finally Land in Inbox

    I started using Mailwarm because I was struggling with my emails going straight to spam, especially for outreach. At first, I wasnโ€™t expecting much, but after a couple of weeks, I actually started noticing a difference. The setup was pretty simple, and once everything was connected, it just kept running in the background without me needing to constantly check it. Thatโ€™s something I really appreciated.

    Overall, Iโ€™d say itโ€™s a reliable tool if youโ€™re serious about improving email deliverability without overcomplicating the process.

    ๐Ÿ Competitors: InboxAlly
  3. Josh
    ยท CTO at Ambas ยท
    A very good email warmup tool

    I have been using Mailwarm to warm up email accounts and improve overall deliverability for my outreach campaigns. The setup process was very simple and everything runs automatically without requiring constant monitoring. Since using the tool, Iโ€™ve seen a clear improvement in inbox placement and fewer emails landing in spam. Itโ€™s a reliable and effective solution for anyone doing cold email or managing multiple inboxes.

    ๐Ÿ Competitors: Warmy.io
    ๐Ÿ‘ Pros:    Very easy and quick to set up|Fully automated email warmup process|Various email providers warmup|Simple, clean dashboard|Very professional and helpful support team

Mailwarm vs Mailreach vs Lemwarm: Which One Fits Your Needs in 2026?
To achieve consistent inbox placement in 2026, choosing the right warm-up tool is crucial. Each solution approaches email warm-up differently. Mailwarm emphasizes large-scale, authentic mailbox interactions. Mailreach is another warm-up tool operating in the same category as Mailwarm, providing similar solutions in automated mailbox interactions for sender reputation...
Top 14 Email Warm-Up Tools for B2B SaaS
Mailwarm: Mailwarm features a maintained network of 2,000+ active mailboxes. It automates opens, replies, spam removal, and marks emails as primary to steadily build sender reputation. The tool focuses on technical deliverability and gradual, natural warm-up.
Top 5 Email Warmup Tools in 2026
Mailwarm is dedicated to building sender reputation rather than marketing automation. Through a network of over 2,000 actively maintained mailboxes, it orchestrates gradual interactions, such as opens, replies, spam recovery, and tagging emails as primary, that help establish a positive sending history. Mailwarm supports all major providers and custom IMAP/SMTP settings and...
23 Best Cold Email WarmUp Tools in 2022 (Free + Paid)
You can visit Mailwarmโ€™s official website and choose the plan which suits you the best for your warm up since it has really great deals, the only drawback is their no free trial which makes it hard to choose this but people do choose because of great deals and features provided by Mailwarm.
Source: inguide.in
Top 10 of the Best Email Warm Up tools in 2022
Mailwarm helps you achieve the required email activity both quantitatively and qualitatively in order to enter the main inbox. The Mailwarm team has set up +1000 email accounts that will interact with your inbox on a schedule you define. The service offers personalized emails designed to mimic human-to-human conversation. Mailwarmโ€™s methods, according to users of the...
Source: mailmeteor.com

Social recommendations and mentions

Based on our record, Clearbit seems to be more popular. It has been mentiond 18 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

Clearbit mentions (18)

  • A Practical Guide To Entity Resolution in Python (No Database, No Machine Learning)
    Some display names need a lookup table, not fuzzy strings. Pairs like Investing.com / Fusion Media Limited or Lyrie.ai / OTT Cybersecurity Inc. Share almost no tokens, so WRatio stays low and that's correct behavior. For irreconcilable aliases like that you still want GLEIF, Clearbit, or simply a maintained slug โ†’ legal_name map. Fuzzy matching handles stylistic drift on the same name; it canโ€™t handle unrelated... - Source: dev.to / about 2 months ago
  • Enriching Free Trial Signups: The PLG Data Stack for Turning Inbound Users Into Qualified Pipeline
    Personal email domains destroy this. Clearbit's Enrichment API returns a null company when it hits gmail.com. Apollo routes personal domains straight to a consumer bucket and skips B2B fields entirely. Even PDL's /person/enrich endpoint โ€” the most permissive of the major providers โ€” gives you around 32% hit rate on Gmail addresses versus 74% on corporate domains. I measured this across 6,200 signups for a... - Source: dev.to / about 2 months ago
  • Clearbit Is Now HubSpot-Only: A 1-to-1 API Migration Map for Teams Getting Locked Out
    A few things worth flagging: PDL beats Clearbit's historical rates for US and Western European companies, but drops to ~52% match rate for Japan and South Korea specifically. Apollo underperforms on raw company matching but returns significantly more contacts per domain in Prospector-style queries than Clearbit's Prospector ever did โ€” the tradeoff is more stale titles in the result set. Hunter.io is fast and cheap... - Source: dev.to / about 2 months ago
  • Reverse Email Lookup Shootout: Hunter, Clearbit, Datagma, and PDL Tested on 500 Real B2B Addresses
    Match rate of 38% in my test, but the data quality on what it does match is solid: title, seniority, industry, company size all returned cleanly. If you're already in HubSpot and enriching form fills in-place, Clearbit/Breeze is probably your lowest-friction option even at lower match rates. If you're not in HubSpot, there's no reason to choose it over PDL or Prospeo. - Source: dev.to / 2 months ago
  • Auto-Enriching Your CRM on New Contact Creation: A No-Code Webhook Playbook
    One thing comparison guides consistently get wrong: Clay is not an enrichment API. It's a waterfall orchestration tool that calls People Data Labs, Apollo, Clearbit, and others in sequence for you. It's useful, but it adds 2โ€“8 seconds of latency per row in my runs and costs more per match than going direct. For a CRM webhook flow where you need sub-second enrichment calls, Clay is the wrong layer to hit first. - Source: dev.to / 2 months ago
View more

Mailwarm mentions (0)

We have not tracked any mentions of Mailwarm yet. Tracking of Mailwarm recommendations started around Mar 2021.

What are some alternatives?

When comparing Clearbit and Mailwarm, you can also consider the following products

Lusha - Search less. Sell more.

Warmbox.ai - Warm up your cold email inbox, and never land in spam anymore!

DiscoverOrg - DiscoverOrg is an IT sales intelligence platform providing technology marketers access to data, IT org charts, and real time projects.

MailReach.co - 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.

Apollo.io - Apolloโ€™s predictive prospecting, sales engagement, and actionable analytics help the teams to reach its full revenue potential.

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.