MailMerge365 Review: Pricing, Pros, Cons & Better Alternatives
You're trying to send a personalized mail merge from Outlook, you've found MailMerge365, and now you want the pricing, reviews, and real pros and cons before committing. The problem? The official site doesn't show prices. Let's fix that.
30-Second Verdict
What Is MailMerge365?
MailMerge365 is a Microsoft 365 add-in built by Sol Inventum (Estonia) that sends personalized mass emails directly from your Outlook mailbox. You build your recipient list in a spreadsheet (CSV or XLSX), map personalization tokens to columns, and the tool handles sending, open/click tracking, bounce detection, and unsubscribe management.
New Outlook's built-in merge doesn't support personalization fields and can't separate To/CC/BCC. It also doesn't give you the kind of campaign tracking most teams want - a Reddit user documenting their experience with New Outlook's mail merge called out these exact gaps. MailMerge365 fills them.
MailMerge365 Pricing Breakdown
Here's the frustrating part: MailMerge365's official site lists three plan types but doesn't show prices. You have to start the checkout flow via Paddle (in EUR) to see what you'll actually pay. That's a red flag.
Here's what we've been able to confirm from the official docs and public directory listings:
| Plan | Price | Limits |
|---|---|---|
| Free trial | €0 | 100 recipients |
| Annual subscription | ~€108/year | 5,000 emails/day |
| Pay-as-you-go | Credit-based (pack pricing not shown publicly) | 1,000 recipients per package |
A few extra details worth knowing. Pay-as-you-go runs on credits: 1 credit = 1 email sent. Payments go through Paddle. Prices display in EUR, and checkout converts to your local currency at the daily rate.
Don't confuse MailMerge365 with EmailMerge365. They're different products from different companies. EmailMerge365 is made by Standss and costs $100/year (Pro) or $200/year with tracking (or $25/month). Different tool, different pricing, similar name. Check which one you're buying.
If you want the vendor's own explanation, see MailMerge365 Pricing Breakdown.
MailMerge365 doesn't verify emails before sending - and Microsoft 365 caps you at 10,000 recipients per day. Every bounce wastes your quota and tanks your domain reputation. Prospeo's 5-step email verification catches invalid addresses, spam traps, and honeypots before you hit send. 98% accuracy at $0.01 per email.
Clean your merge list before Microsoft punishes you for it.
Pros and Cons
Pros:
- Sends from your own mailbox - better deliverability than third-party senders
- Open, click, and bounce tracking built in (see email tracking pixels if you want the mechanics)
- Unsubscribe management with automatic detection
- Easy setup - G2 reviewers highlight that "once you have a template it's easy to set up"
- Follow-ups to non-responders and link clickers (use these sales follow-up templates if you need copy)
- Scheduling and rate limiting to stay within Microsoft 365 caps (more on safe email velocity)
Cons:
- Pricing isn't published on the website - you discover costs at checkout
- Only 2 G2 reviews, so there's almost no independent review signal
- "Free" limits can be confusing: the official trial is 100 recipients, but a G2 reviewer mentions a 50-email limit and unreliable tracking on the free tier
- No built-in email verification - bounces damage your domain reputation (and you can benchmark your email bounce rate)
- Bound by Microsoft 365 sending limits with no way to bypass them
The M365 Sending Limit Problem
Every Outlook mail merge tool - MailMerge365 included - hits Microsoft 365's hard sending caps. Exchange Online limits every mailbox to 10,000 recipients per rolling 24-hour period and 500 recipients per single message. These limits can't be increased.
MailMerge365 advertises 5,000 emails per day, a conservative buffer below Microsoft's ceiling. But if you're sending to a list full of bad emails, you're burning through your daily quota on bounces that never reach anyone. MailMerge365 can detect bounces after the fact. That's not the same as pre-send verification.
Here's the thing: if your list isn't verified before you hit send, the mail merge tool you pick barely matters. A 10% bounce rate on a 2,000-person merge wastes 200 sends and puts your domain reputation at risk. Verify first, merge second.
We've seen teams cut bounce rates from 35%+ down to under 4% just by running their lists through Prospeo's email verification before sending. The 5-step verification process catches invalid addresses, spam traps, and honeypots before they waste your sending quota. (If you're comparing tools, start with these Bouncer alternatives.) The free tier gives you 75 verifications per month - enough to clean a small merge list before every campaign.
Teams using MailMerge365 without pre-send verification see bounce rates above 10%. One Prospeo customer cut bounces from 35% to under 4% - tripling their pipeline in the process. The free tier gives you 75 email verifications per month, enough to clean a small campaign before every send.
Stop burning your Outlook sending quota on dead emails.
What Users Say in Reviews
Two G2 reviews isn't enough to draw meaningful conclusions. But here's what they say.
The positive review (5/5, January 2026) highlights "ease of set up" and calls open rate tracking "very smooth." The older review (3.5/5, February 2023, incentivized) flags that the free version's tracking "doesn't sometimes work" and mentions disconnection issues.
One oddity: the G2 listing references Gmail and Google Sheets in review text, which creates ecosystem confusion for a product marketed as an Outlook add-in. G2 may be conflating products under the "MailMerge" name - take the reviews with that context in mind.
Top Alternatives Compared
| Tool | Platform | Price | Best For |
|---|---|---|---|
| SecureMailMerge | Outlook | Free / $10-15/user/mo | Privacy-first Outlook merge |
| EmailMerge365 | Outlook | $100/yr or $200/yr (tracking) | Known pricing, scheduling |
| GMass | Gmail | From $12.95/mo | Gmail power users |
| Mailmeteor | Gmail | From $49.99/yr | Simple, occasional sends |
For most Outlook users, SecureMailMerge is the default pick. MailMerge365 only makes sense if you specifically need open/click tracking and don't mind opaque pricing.
Other Outlook options include Mail Merge Toolkit ($30-99/year), Topalt ($16/month), and Sperry Send Individually ($20 one-time) - but none match SecureMailMerge's free tier or MailMerge365's tracking depth.
SecureMailMerge
Use this if you want a free Outlook mail merge tool with transparent licensing and strong privacy guarantees. Skip this if you need built-in open/click tracking on the free tier.
SecureMailMerge is free for non-commercial use. Commercial licenses typically run $10-$15/user/month. The privacy angle is real - your data never gets uploaded to any servers. There are no restrictions on the number of campaigns, emails, or attachments, though Microsoft 365 and org-level limits still apply. Volume discounts kick in at 10+ licenses via Microsoft AppSource.
EmailMerge365
Don't let the name fool you - this is a completely separate product by Standss. $100/year for Pro, $200/year (or $25/month) with open and click tracking. The tracking tier caps at 200 emails per tracked merge, with unlimited untracked merges. The biggest advantage over MailMerge365? You can see exactly what you'll pay before you commit.
GMass
Gmail-only. From $12.95/month. Well-established with a massive review base - the polar opposite of MailMerge365's social proof problem. If you aren't locked into Outlook, GMass is the most battle-tested mail merge option available. If you're doing outbound at scale, consider a dedicated AI bulk email sender instead of forcing Outlook.
Mailmeteor
Gmail-only. From $49.99/year. Generous free tier and dead-simple interface. Good for occasional senders who don't need advanced tracking or automation.
FAQ
How much does MailMerge365 cost?
MailMerge365 offers a free trial (100 recipients), an annual subscription, and pay-as-you-go credits. Exact prices aren't published on the official site - you'll see them at checkout via Paddle in EUR. Public directories list the annual plan at ~€108/year.
Is MailMerge365 legit?
It's a real product by Sol Inventum (Estonia) with a functional Outlook add-in. With only 2 G2 reviews and limited independent coverage, social proof is thin. The tool works for Outlook-based sending plus tracking, but you're buying with less third-party validation than most email tools offer.
How do I prevent bounces in a mail merge?
Verify your email list before sending. Prospeo delivers 98% email accuracy with a free tier (75 verifications per month), catching invalid addresses and spam traps before they waste your Microsoft 365 daily sending quota and damage your domain reputation.