Boost Inbox vs GMass: Email Warmup Tool vs Cold Email Platform Comparison
Compare Boost Inbox (email warmup tool) and GMass (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 starting at $5/mo that builds sender reputation and inbox placement, while GMass is a Gmail-based cold email platform starting at $29.95/mo for sending outreach campaigns. They solve different parts of the same workflow, deliverability versus outreach, and many teams use both together.
Key takeaways
- Boost Inbox starts at $5/mo for its Starter plan with one mailbox for warmup and 50 daily positive engagements.
- GMass starts at $29.95/mo for its Standard plan with unlimited contacts and emails, subject to Gmail limits.
- GMass offers 4 pricing tiers, including a $175/mo Teams plan for 5 users, compared to Boost Inbox's 3 tiers.
- Boost Inbox lists 8 features including an email health checker tool and inbox reputation analytics, while GMass lists 10 features including Spam Solver and API and Zapier access.
- Boost Inbox integrates with 6 platforms including GSuite, Outlook 365, and Amazon SES, while GMass integrates with Google Sheets, Zapier, and Google Workspace, with Gmail as a shared integration.
Reviewed and updated September 2, 2026
Boost Inbox vs GMass: Email Warmup Tool vs Cold Email Platform Comparison
Boost Inbox (email warmup tool) and GMass (cold email platform) 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
Boost Inbox is an email warmup tool for email domain warming and deliverability; GMass is a cold email platform for cold email outreach. By each vendor's own wording, Boost Inbox lists email warmup and fully automated, and GMass lists works inside gmail and unlimited emails, contacts, and campaigns.
Boost Inbox offers a lower entry point at $5/mo compared to GMass at $29.95/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 GMass. 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.
GMass is Gmail-based mass email and mail merge platform with unlimited emails, campaigns, and contacts directly inside Gmail.
The two platforms take different approaches to solving the same core challenge.
Pricing Comparison
Starter
Standard
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
GMass Pricing (as of September 2026)
| Plan | Price | Contacts | Emails |
|---|---|---|---|
| Standard | $29.95/mo | Unlimited | Unlimited (Gmail limits apply) |
| Premium | $39.95/mo | Unlimited | Unlimited (Gmail limits apply) |
| Professional | $59.95/mo | Unlimited | Unlimited (Gmail limits apply) |
| Teams (5 users) | $175/mo | Unlimited | Unlimited (Gmail limits apply) |
Source: GMass Pricing
Pricing Analysis
Boost Inbox is more affordable at the entry level ($5/mo vs $29.95/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.
GMass offers 4 pricing tiers compared to Boost Inbox's 3, giving you more granularity as you scale.
Features Breakdown
- Email Warmup
- Fully Automated
- Status Reports
- Human Review
- Premium Support
- Realistic emails sent from your inbox daily
- and 2 more listed below
- Works inside Gmail
- Unlimited emails, contacts, and campaigns
- Mail merge personalization
- Free email verification
- Automated follow-up sequences
- A/B testing
- and 4 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
GMass Key Features
- Works inside Gmail
- Unlimited emails, contacts, and campaigns
- Mail merge personalization
- Free email verification
- Automated follow-up sequences
- A/B testing
- Spam Solver deliverability tool
- Custom tracking links
- Inbox rotation
- API and Zapier access
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 GMass
- Works inside Gmail
- Unlimited emails, contacts, and campaigns
- Mail merge personalization
- Free email verification
- Automated follow-up sequences
- A/B testing
- Spam Solver deliverability tool
- Custom tracking links
- Inbox rotation
- API and Zapier access
Integration Ecosystem
Boost Inbox Integrations
Boost Inbox connects with: Gmail, GSuite, Outlook 365, Yahoo Mail, Amazon SES, SMTP.
GMass Integrations
GMass connects with: Gmail, Google Sheets, Zapier, Google Workspace.
Shared Integrations
Both tools integrate with: Gmail.
Integrations listed only by Boost Inbox: GSuite, Outlook 365, Yahoo Mail, Amazon SES, SMTP.
Integrations listed only by GMass: Google Sheets, Zapier, Google Workspace.
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 GMass
- Budget-conscious teams looking for an affordable cold email platform
- Teams that need a wide feature set (10 capabilities listed)
- Sales teams running high-volume outbound email campaigns
- Agencies managing multiple client outreach programs
Feature Comparison Summary
| Feature | Boost Inbox | GMass |
|---|---|---|
| Starting Price | $5/mo | $29.95/mo |
| Top Tier Price | $19/mo | $175/mo |
| Total Features Listed | 8 | 10 |
| Integrations | 6 | 4 |
| Founded | N/A | 2015 |
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 GMass the cold email outreach side. Boost Inbox offers a more accessible entry point at $5/mo, while GMass starts at $29.95/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 GMass for current information.
Frequently asked questions.
Frequently asked questions- What is the main difference between Boost Inbox and GMass?
- Boost Inbox is an email warmup tool focused on building sender reputation and deliverability, while GMass is a cold email platform focused on sending outreach campaigns from Gmail. Boost Inbox gradually increases sending activity to build trust with email providers, whereas GMass handles mail merge, follow-ups, and campaign sending.
- How much does Boost Inbox cost compared to GMass?
- Boost Inbox starts at $5/mo for its Starter plan, while GMass starts at $29.95/mo for its Standard plan. Boost Inbox has 3 pricing tiers topping out at $19/mo for Premium, while GMass has 4 tiers including a $175/mo Teams plan for 5 users.
- Do I need both Boost Inbox and GMass?
- Many teams run both, since Boost Inbox handles email domain warming and deliverability while GMass handles cold email outreach. If the priority is building sender reputation, Boost Inbox fits that need, and if the priority is sending campaigns that land in the inbox and generate replies, GMass fits that need.
- What integrations does GMass support?
- GMass connects with Gmail, Google Sheets, Zapier, and Google Workspace. Gmail is the only integration shared with Boost Inbox, while Google Sheets, Zapier, and Google Workspace are listed only by GMass.
- Who is Boost Inbox best suited for?
- Boost Inbox is best suited for budget-conscious teams needing an affordable email warmup tool, organizations with complex tech stacks needing broad integration support across 6 integrations, teams launching new email domains for outreach, and organizations recovering from deliverability issues.
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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