Mailwarm

Mailwarm is an automated email warmup and deliverability platform designed to help businesses improve inbox placement and avoid spam filtering. Founded in 2020 in Rouen, France, Mailwarm supports founders, sales teams, marketers, recruiters, agencies, and outbound teams that rely on cold email and outbound campaigns for growth.

The platform focuses on long-term sender reputation building through consistent, natural engagement signals rather than short-term tactics. By generating realistic interactions between real email accounts, Mailwarm helps strengthen domain, inbox, and SMTP reputation across major mailbox providers including Gmail, Outlook, Microsoft 365, and Yahoo.

Core Capabilities

Automated Email Warmup

Mailwarm automatically warms new domains, mailboxes, and SMTP servers through multi-provider engagement. This process simulates authentic email activity to build trust with mailbox providers and improve inbox placement rates.

Multi-Provider Infrastructure

Unlike single-provider warmup systems, Mailwarm supports Gmail, Outlook, Microsoft 365, and Yahoo simultaneously. This creates diversified engagement signals and more realistic reputation building.

Spam Score Tracking

Mailwarm provides measurable spam score tracking to monitor inbox vs. spam performance over time. This visibility allows teams to evaluate deliverability progress and adjust outreach strategy accordingly.

Bounce Prevention & Verification

Built-in verification systems help reduce bounce rates and protect sender reputation, a critical factor in maintaining strong deliverability metrics.

SMTP, Domain & Mailbox Warmup

The platform supports warmup at multiple levels, domain; SMTP server, and individual mailbox; offering flexibility for startups launching new domains or agencies managing multiple client accounts.

Outlook & Office365 One-Click Connection

Mailwarm offers simplified integration with Outlook and Microsoft 365, along with guided SMTP setup and continuous deliverability monitoring.

Stable Automation & Auto-Recovery

The system includes automated recovery mechanisms to maintain warmup stability in case of connection issues, ensuring consistent reputation building.

Team & Agency Management

Flexible plans and multi-account management tools allow agencies and sales teams to manage multiple inboxes and client domains from a centralized dashboard.

Differentiation

Mailwarm emphasizes measurable deliverability improvement through structured engagement and transparent tracking. Its multi-provider warmup system, spam score visibility, bounce prevention features, and stable automation infrastructure distinguish it from tools that rely on limited engagement networks or opaque performance metrics.

The platform was developed after its founders experienced repeated spam placement while running outreach campaigns. After internal testing and iteration within the Station F startup ecosystem, the solution was launched publicly and later accepted into Y Combinator. Mailwarm has since grown into a deliverability platform used by startups, agencies, recruitment firms, SaaS companies, e-commerce brands, and outbound sales teams across global markets.

Mailwarm is designed for organizations that depend on reliable email outreach and require a structured, data-driven approach to sender reputation management and inbox placement improvement.