MailRush.io vs Warmup Inbox: Cold Email Platform vs Email Warmup Tool Comparison
Compare MailRush.io (cold email platform) and Warmup Inbox (email warmup tool) side by side. See pricing, features, and integrations to decide which one, or both, your stack needs.
MailRush.io is a cold email platform built for sending outreach campaigns and follow-ups, while Warmup Inbox is an email warmup tool built for building sender reputation and inbox placement. Both start at $19/mo. Teams focused on sending campaigns and replies should choose MailRush.io; teams focused on deliverability and reputation should choose Warmup Inbox. Many teams use both together.
Key takeaways
- MailRush.io and Warmup Inbox both start at the same $19/mo price point.
- MailRush.io's top tier is Scale at $99/mo with up to 50,000 contacts and 25,000 emails per month.
- Warmup Inbox's Max plan costs $99/mo and provides 1,000 warmup messages per day per inbox.
- Warmup Inbox exchanges email with a network of more than 30,000 real inboxes to build sender reputation.
- MailRush.io lists 11 features including unlimited senders and unlimited email warming, while Warmup Inbox lists 9 features including language warmup and IP warmup.
Reviewed and updated September 2, 2026
MailRush.io vs Warmup Inbox: Cold Email Platform vs Email Warmup Tool Comparison
MailRush.io (cold email platform) and Warmup Inbox (email warmup tool) sit next to each other in many outbound stacks. They are not substitutes for each other on every job, so this comparison covers pricing, features, and integrations for each and points out where the two meet.
The Quick Answer
MailRush.io is a cold email platform for cold email outreach; Warmup Inbox is an email warmup tool for email domain warming and deliverability. By each vendor's own wording, MailRush.io lists unlimited senders and unlimited email warming, and Warmup Inbox lists email warmup and cold email sequence.
Both start at the same price point ($19/mo), so the decision comes down to features and workflow fit.
If your priority is sending campaigns that land in the inbox and generate replies, MailRush.io is the one built for it; for building sender reputation and improving inbox placement, that is Warmup Inbox. Many teams run one of each.
Understanding the Core Difference
MailRush.io is Cold email software that automates outreach and multi-step follow-ups from your own SMTP/IMAP mailboxes or MailRush-provided sending accounts. Email warmup and email validation are included in every plan.
Warmup Inbox is Email warmup service that exchanges natural-looking email with a network of more than 30,000 real inboxes to build sender reputation automatically. Also offers cold email sequences, language warmup, ESP warmup and IP warmup from the same dashboard.
The two platforms take different approaches to solving the same core challenge.
Pricing Comparison
MailRush.io Pricing (as of September 2026)
| Plan | Price | Contacts | Emails |
|---|---|---|---|
| Starter | $19/mo | Up to 1,000 contacts | Up to 5,000 emails per month; up to 1,000 emails per day |
| Pro | $39/mo | Up to 30,000 contacts | Up to 10,000 emails per month; up to 1,500 emails per day |
| Scale | $99/mo | Up to 50,000 contacts | Up to 25,000 emails per month; up to 3,000 emails per day |
Source: MailRush.io Pricing
Warmup Inbox Pricing (as of September 2026)
| Plan | Price | Contacts | Emails |
|---|---|---|---|
| Basic | $19/mo | per inbox | 75 warmup messages/day |
| Pro | $59/mo | per inbox | 250 warmup messages/day |
| Max | $99/mo | per inbox | 1,000 warmup messages/day |
| For agencies & teams | Contact Sales | Custom plans starting at 15 inboxes | custom |
Source: Warmup Inbox Pricing
Pricing Analysis
Both platforms start at the same $19/mo price point. The decision comes down to which feature set and tier structure works better for your expected usage.
Warmup Inbox offers 4 pricing tiers compared to MailRush.io's 3, giving you more granularity as you scale.
Features Breakdown
- Unlimited senders
- Unlimited email warming
- Email validation
- API access & Webhooks
- Zapier integrations
- Spintax support
- and 5 more listed below
- Email warmup
- Cold email sequence
- Language warmup
- ESP warmup tool
- IP warmup
- Spam & Category monitoring
- and 3 more listed below
MailRush.io Key Features
- Unlimited senders
- Unlimited email warming
- Email validation
- API access & Webhooks
- Zapier integrations
- Spintax support
- Email follow-ups
- Suppression list
- Email copy spam assessment
- Email personalization
- Unsubscription automation
Warmup Inbox Key Features
- Email warmup
- Cold email sequence
- Language warmup
- ESP warmup tool
- IP warmup
- Spam & Category monitoring
- Email reputation Check
- Human-like AI generated content
- Developers API
The two lists below are a diff of each vendor's own feature list by exact wording, so a capability both tools offer can appear on either side under a different name.
Listed only by MailRush.io
- Unlimited senders
- Unlimited email warming
- Email validation
- API access & Webhooks
- Zapier integrations
- Spintax support
- Email follow-ups
- Suppression list
- Email copy spam assessment
- Email personalization
- Unsubscription automation
Listed only by Warmup Inbox
- Email warmup
- Cold email sequence
- Language warmup
- ESP warmup tool
- IP warmup
- Spam & Category monitoring
- Email reputation Check
- Human-like AI generated content
- Developers API
Integration Ecosystem
MailRush.io Integrations
MailRush.io connects with: SMTP, IMAP, Zapier, Webhooks.
Warmup Inbox Integrations
Warmup Inbox connects with: Gmail & Workspace, Outlook & Microsoft 365, Zoho Mail, Amazon SES, Mailgun, SendGrid, Sendinblue (Brevo), Any inbox with SMTP.
Integrations listed only by MailRush.io: SMTP, IMAP, Zapier, Webhooks.
Integrations listed only by Warmup Inbox: Gmail & Workspace, Outlook & Microsoft 365, Zoho Mail, Amazon SES, Mailgun, SendGrid, Sendinblue (Brevo), Any inbox with SMTP.
Use Case Recommendations
Best Fit for MailRush.io
- Budget-conscious teams looking for an affordable cold email platform
- Teams that need a wide feature set (11 capabilities listed)
- Sales teams running high-volume outbound email campaigns
- Agencies managing multiple client outreach programs
Best Fit for Warmup Inbox
- Budget-conscious teams looking for an affordable email warmup tool
- Organizations with complex tech stacks needing broad integration support (8 integrations)
- Enterprise buyers who prefer custom pricing and dedicated support
Feature Comparison Summary
| Feature | MailRush.io | Warmup Inbox |
|---|---|---|
| Starting Price | $19/mo | $19/mo |
| Top Tier Price | $99/mo | Contact Sales |
| Total Features Listed | 11 | 9 |
| Integrations | 4 | 8 |
Getting Started Checklist
- Define your cold email outreach and email domain warming and deliverability requirements and monthly budget
- Estimate your expected email sending volume and warmup email volume to find the right tier
- List the integrations your team currently relies on
- Sign up for free trials or demos of both platforms
- Run a small test with each tool before making a commitment
- Evaluate the onboarding experience and support quality
Final Thoughts
MailRush.io serves the cold email outreach side of an outbound stack and Warmup Inbox the email domain warming and deliverability side. MailRush.io offers a more accessible entry point at $19/mo, while Warmup Inbox starts at $19/mo. Your decision should weigh pricing against the specific features that matter most for your workflow.
Start with a trial of each to see which platform fits your team's daily process. The best tool is the one your team actually uses consistently.
Pricing and features verified as of September 2026. Visit MailRush.io and Warmup Inbox for current information.
Frequently asked questions.
Frequently asked questions- What is the main difference between MailRush.io and Warmup Inbox?
- MailRush.io is a cold email platform for sending outreach campaigns and automated follow-ups, while Warmup Inbox is an email warmup tool for building sender reputation and improving inbox placement. They solve different parts of the outbound email workflow, and many teams use both together.
- How much do MailRush.io and Warmup Inbox cost?
- Both platforms start at $19/mo. MailRush.io's tiers go up to Scale at $99/mo with up to 50,000 contacts and 25,000 emails per month. Warmup Inbox's tiers go up to Max at $99/mo per inbox with 1,000 warmup messages per day, plus a custom agency plan starting at 15 inboxes.
- Does MailRush.io include email warmup?
- Yes, MailRush.io includes email warmup and email validation in every plan, and lists unlimited email warming as one of its features. However, Warmup Inbox is built specifically as a dedicated warmup tool with a network of more than 30,000 real inboxes for building sender reputation.
- What integrations does Warmup Inbox support?
- Warmup Inbox connects with Gmail and Workspace, Outlook and Microsoft 365, Zoho Mail, Amazon SES, Mailgun, SendGrid, Sendinblue (Brevo), and any inbox with SMTP. That is eight integrations total, compared to MailRush.io's four listed integrations of SMTP, IMAP, Zapier, and Webhooks.
- Which tool should I choose if I run outbound campaigns for an agency?
- MailRush.io is recommended for agencies managing multiple client outreach programs since it offers a wide feature set of 11 capabilities aimed at sending campaigns and generating replies. Warmup Inbox is better suited for organizations with complex tech stacks needing broad integration support or enterprise buyers wanting custom pricing.
About the author.
Tim Carden is CMO / CTO at RevenueFlow, which builds and operates outbound revenue engines for B2B companies. Studied at McGill University.
Tim Carden · CMO / CTO
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