Boost Inbox vs MailRush.io: Email Warmup Tool vs Cold Email Platform Comparison
Compare Boost Inbox (email warmup tool) and MailRush.io (cold email platform) side by side. See pricing, features, and integrations to decide which one, or both, your stack needs.
Boost Inbox is an email warmup tool for domain warming and deliverability, priced from $5/mo, while MailRush.io is a cold email platform for outreach, priced from $19/mo. Boost Inbox builds sender reputation through daily simulated engagement; MailRush.io automates campaigns and follow-ups, with warmup and validation built into every plan. Many teams run both together.
Key takeaways
- Boost Inbox starts at $5/mo for the Starter plan covering one mailbox for warmup with 50 daily positive engagements.
- MailRush.io starts at $19/mo for the Starter plan covering up to 1,000 contacts and up to 5,000 emails per month.
- MailRush.io's Scale plan at $99/mo supports up to 50,000 contacts and up to 25,000 emails per month.
- Boost Inbox integrates with Gmail, GSuite, Outlook 365, Yahoo Mail, Amazon SES, and SMTP, while MailRush.io integrates with SMTP, IMAP, Zapier, and Webhooks.
- MailRush.io lists 11 features including unlimited senders, unlimited email warming, and API access and webhooks, compared to 8 features listed by Boost Inbox.
Reviewed and updated September 2, 2026
Boost Inbox vs MailRush.io: Email Warmup Tool vs Cold Email Platform Comparison
Sales teams building an outbound stack often weigh Boost Inbox, an email warmup tool for email domain warming and deliverability, against MailRush.io, a cold email platform for cold email outreach. They cover different parts of the workflow, so this comparison covers what each one does, what each one costs, and where they overlap.
The Quick Answer
Boost Inbox is an email warmup tool for email domain warming and deliverability; MailRush.io is a cold email platform for cold email outreach. By each vendor's own wording, Boost Inbox lists email warmup and fully automated, and MailRush.io lists unlimited senders and unlimited email warming.
Boost Inbox offers a lower entry point at $5/mo compared to MailRush.io at $19/mo.
If your priority is building sender reputation and improving inbox placement, Boost Inbox is the one built for it; for sending campaigns that land in the inbox and generate replies, that is MailRush.io. Many teams run one of each.
Understanding the Core Difference
Boost Inbox is Email warmup service that gradually increases sending activity to build trust with email providers. It sends realistic emails from your inbox on a daily basis, keeps them out of spam, opens and bookmarks them, and replies to a portion of them to generate positive interactions.
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.
The two platforms take different approaches to solving the same core challenge.
Pricing Comparison
Starter
Starter
Boost Inbox Pricing (as of September 2026)
| Plan | Price | Contacts | Emails |
|---|---|---|---|
| Starter | $5/mo | 1 Mailbox For Warmup | 50 Daily Positive Engagement |
| Team | $9/mo | 3 Mailboxes For Warmup | 50 Daily Positive Engagement per mailbox |
| Premium | $19/mo | 8 Mailboxes For Warmup | 50 Daily Positive Engagement per mailbox |
Source: Boost Inbox Pricing
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
Pricing Analysis
Boost Inbox is more affordable at the entry level ($5/mo vs $19/mo). For teams with tight budgets or those just getting started with email domain warming and deliverability and cold email outreach, this price difference matters.
Features Breakdown
- Email Warmup
- Fully Automated
- Status Reports
- Human Review
- Premium Support
- Realistic emails sent from your inbox daily
- and 2 more listed below
- Unlimited senders
- Unlimited email warming
- Email validation
- API access & Webhooks
- Zapier integrations
- Spintax support
- and 5 more listed below
Boost Inbox Key Features
- Email Warmup
- Fully Automated
- Status Reports
- Human Review
- Premium Support
- Realistic emails sent from your inbox daily
- Email health checker tool
- Inbox reputation analytics
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
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 Boost Inbox
- Email Warmup
- Fully Automated
- Status Reports
- Human Review
- Premium Support
- Realistic emails sent from your inbox daily
- Email health checker tool
- Inbox reputation analytics
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
Integration Ecosystem
Boost Inbox Integrations
Boost Inbox connects with: Gmail, GSuite, Outlook 365, Yahoo Mail, Amazon SES, SMTP.
MailRush.io Integrations
MailRush.io connects with: SMTP, IMAP, Zapier, Webhooks.
Shared Integrations
Both tools integrate with: SMTP.
Integrations listed only by Boost Inbox: Gmail, GSuite, Outlook 365, Yahoo Mail, Amazon SES.
Integrations listed only by MailRush.io: IMAP, Zapier, Webhooks.
Use Case Recommendations
Best Fit for Boost Inbox
- Budget-conscious teams looking for an affordable email warmup tool
- Organizations with complex tech stacks needing broad integration support (6 integrations)
- Teams launching new email domains for outreach
- Organizations recovering from deliverability issues
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
Feature Comparison Summary
| Feature | Boost Inbox | MailRush.io |
|---|---|---|
| Starting Price | $5/mo | $19/mo |
| Top Tier Price | $19/mo | $99/mo |
| Total Features Listed | 8 | 11 |
| Integrations | 6 | 4 |
Getting Started Checklist
- Define your email domain warming and deliverability and cold email outreach requirements and monthly budget
- Estimate your expected warmup email volume and email sending 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
Boost Inbox serves the email domain warming and deliverability side of an outbound stack and MailRush.io the cold email outreach side. Boost Inbox offers a more accessible entry point at $5/mo, while MailRush.io 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 Boost Inbox and MailRush.io for current information.
Frequently asked questions.
Frequently asked questions- What's the main difference between Boost Inbox and MailRush.io?
- Boost Inbox is an email warmup tool focused on domain warming and deliverability, while MailRush.io is a cold email platform focused on outreach and follow-ups. Boost Inbox builds sender reputation by sending realistic daily emails, opening and replying to them, whereas MailRush.io automates multi-step campaigns from your own mailboxes or its provided sending accounts.
- Which tool is cheaper, Boost Inbox or MailRush.io?
- Boost Inbox has the lower entry price at $5/mo compared to MailRush.io's $19/mo Starter plan. Boost Inbox's Premium plan tops out at $19/mo for 8 mailboxes, while MailRush.io's Scale plan reaches $99/mo for up to 50,000 contacts.
- Does MailRush.io include email warmup?
- Yes, MailRush.io includes email warmup and email validation in every plan, alongside features like unlimited senders, API access and webhooks, Zapier integrations, and spintax support. This differs from Boost Inbox, which is dedicated solely to warmup rather than full campaign automation.
- Can I use Boost Inbox and MailRush.io together?
- Yes, the article notes that many teams run one of each since they cover different parts of the outbound workflow. Boost Inbox handles sender reputation and inbox placement, while MailRush.io handles sending campaigns and generating replies.
- Which integrations does each tool support?
- Boost Inbox connects with Gmail, GSuite, Outlook 365, Yahoo Mail, Amazon SES, and SMTP. MailRush.io connects with SMTP, IMAP, Zapier, and Webhooks. The only integration listed by both tools is SMTP.
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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