The short answer
Trend Micro Email Security suits organizations that want sandboxing, a continuity mailbox, a ten-day queue and a route into Trend's wider Vision One platform, and that are happy to buy per user on an annual contract. iBlockSpam suits businesses that want inbound filtering at a published per-domain price, unlimited mailboxes, flexible quarantine digests, free DNS tools and a 30-day money-back guarantee.
Trend now brands the product TrendAI Email Security, and offers an update path to Cloud Email Gateway Protection inside TrendAI Vision One. Competitor details below were checked on Trend's own pages and online help in October 2026. Prices and packaging change; confirm them before you decide.
Side by side
| Item | Trend Micro (TrendAI) Email Security | iBlockSpam |
|---|---|---|
| Deployment | Cloud gateway: your MX record points to Trend, which becomes "the point of entry" for your mail | Cloud gateway: your MX record points to our filtering servers |
| Pricing model | "Per user basis under an annual contract"; seats based on addresses registered to the domain. In Vision One, Cloud Email Gateway Protection uses 25 credits per user account or email address | Per domain, unlimited mailboxes (mailbox count, not message volume) |
| Published price | None on the pages we checked; Trend says the cost per user drops as user numbers rise | Protect $12 per domain/month billed annually ($144/year) or $15 month-to-month; Protect Plus $19 annually or $24 monthly. Beta pricing, USD, excluding tax |
| Editions | Standard and Advanced (Advanced adds Virtual Analyzer, Email Continuity, BEC writing-style analysis, DMARC report analysis and a 150 MB message limit) | Protect and Protect Plus, with the same filtering on both |
| Trial or guarantee | Trial on a limited number of addresses; 30-day trial of the TrendAI Vision One platform | No free trial; 30-day money-back guarantee on a domain's first annual subscription |
| If your server is down | A queue of up to 10 days; Email Continuity standby email system on Advanced | Spooled for up to 5 days |
| Quarantine and digests | Digest rules daily at set times or weekly on chosen days; up to 100 messages per digest, optional inline actions; quarantine kept 30 days | Personal quarantine for every user; digests hourly, daily, on a chosen weekday or custom; shared admin quarantine |
| Sandboxing | Virtual Analyzer for files and URLs (Advanced) | No |
| Message size | 50 MB (Standard), 150 MB (Advanced) | Up to 400 MB inbound |
| Outbound | Optional outbound routing through Trend's MTAs | Outbound relay with DKIM signing and outbound filtering, 500 messages a month |
| Setup | Add the domain, allow Trend's IP ranges, set up Microsoft 365 connectors where used, then change MX; Trend notes DNS can take up to 48 hours | MX change plus platform steps, with a guided setup wizard and rollback steps |
| Free tools | Not listed on the pages we checked | Email Health Check, MX, SPF, DKIM, DMARC, blacklist, PTR, MTA-STS, BIMI, header analyzer, SPF and DMARC generators |
Trend also sells an API product, Cloud App Security (in Vision One, existing instances can be updated to Cloud Email and Collaboration Protection). It scans Microsoft 365 and Gmail mailboxes through the providers' APIs, or inline with no MX change, so it isn't a gateway. This page compares the gateway product. Our guide to gateways vs API email security explains the difference.
What it costs at 10 and 50 mailboxes
Assumptions: one domain, published prices only, USD, excluding tax.
| Item | 10 mailboxes | 50 mailboxes |
|---|---|---|
| Trend Micro (TrendAI) Email Security | Not published | Not published |
| iBlockSpam Protect, annual | $12/month ($144/year) | $12/month ($144/year) |
| iBlockSpam Protect Plus, annual | $19/month ($228/year) | $19/month ($228/year) |
| iBlockSpam Protect, month-to-month | $15/month | $15/month |
Trend prices Email Security per user on an annual contract, and Vision One prices Cloud Email Gateway Protection in credits; we found no current list price for either on Trend's pages. Ask Trend or a Trend partner for a quote, and check whether aliases and shared addresses count as seats, since Trend's licence count is based on addresses registered to the domain. For more than one domain, see per-domain vs per-user pricing.
When Trend Micro Email Security is the better choice
- You want attachment and URL sandboxing. Email Security Advanced includes Virtual Analyzer. iBlockSpam doesn't sandbox.
- You need a longer outage buffer. Trend queues mail for up to ten days, against our five, and Advanced adds a continuity mailbox.
- You already use Trend Micro or Vision One. Email Security can be updated to Cloud Email Gateway Protection and managed alongside Trend's other products.
- You want outbound encryption, DMARC report analysis or BEC writing-style analysis from your filtering vendor. Email Security can encrypt outbound mail through policy rules, and the Advanced licence adds DMARC report analysis and writing-style analysis for BEC.
- You'd rather scan mailboxes by API than change MX. Trend's Cloud App Security does that; iBlockSpam is MX-only.
When iBlockSpam is the better choice
- You want a price you can read before you talk to anyone. Prices and per-domain limits are on the pricing page.
- You have many mailboxes, shared addresses or aliases. One price per domain covers unlimited mailboxes and domain aliases, with 100,000 inbound messages a month.
- You want users to choose how often they hear about held mail. Digests can run hourly, daily, on a chosen weekday or custom.
- You want filtering without a platform contract. Pay per domain, annually or month to month, and cancel in the billing portal, effective at period end.
- You want DNS drift alerts and free tools. Domain monitoring is included, and our tools need no sign-up.
- Five days of outage spooling is enough for you, and you'd rather keep the setup simple.
How to switch from Trend Micro Email Security
- Check your Trend contract end date and notice terms, so you don't pay for an overlap you don't need.
- Export approved and blocked sender lists, and note any policies you rely on, such as attachment rules.
- Save your current DNS with the Email Health Check and lower the MX TTL a day or two ahead.
- Add your domain in iBlockSpam and follow the guided setup for your platform, such as the Microsoft 365 inbound connector or the Google Workspace inbound gateway.
- Update any connector or firewall rule that only accepts mail from Trend's IP ranges, move your outbound route if it runs through Trend, and remove Trend's include from your SPF record once outbound mail no longer uses it.
- Change MX, test with the Email Header Analyzer, and keep Trend active until the old TTL has passed and no new mail arrives there.
Our migration plan covers each step and the rollback. The guide to switching spam filter providers explains why mail goes missing during a cutover and how to avoid it.
Trend Micro, TrendAI, Trend Vision One, TrendAI Vision One and Cloud App Security are trademarks of Trend Micro Incorporated; iBlockSpam is not affiliated with Trend Micro.
Sources
Checked October 2026.
- TrendAI Email Security online help: FAQs and instructions (per-user annual pricing, cost per user drops with volume, no set-up fee, 10-day queue, Email Continuity, trial on limited addresses, outbound routing, 30-day quarantine storage)
- TrendAI Email Security online help: available license versions (Standard vs Advanced, Virtual Analyzer, continuity, message size limits)
- TrendAI Email Security online help: configure a domain (MX records, IP ranges, Microsoft 365 connectors, outbound MTAs, 48-hour propagation)
- TrendAI Email Security online help: quarantine digest settings (up to 100 messages, inline actions)
- TrendAI Email Security online help: adding or editing a digest rule (daily or weekly schedule)
- Trend Micro support: incoming mail kept for 10 days while the receiving server is down
- Trend Micro support: Email Security licensing FAQ (seats based on addresses registered to the domain)
- TrendAI Email Security online help: update to Cloud Email Gateway Protection
- Trend Vision One online help: credit requirements for Email and Collaboration Security (25 credits per user account or email address for Cloud Email Gateway Protection; how users are counted)
- TrendAI Email Security online help: encrypting outbound messages (Encrypt email action in outbound policy rules)
- Trend Vision One online help: updating Cloud App Security to Cloud Email and Collaboration Protection
- Cloud App Security online help: protection modes (API-based and inline, no MX change)
- TrendAI: Email Security platform page (no published prices)
- TrendAI: free trial (30-day TrendAI Vision One trial)
Frequently asked questions
How does Trend Micro count users for Email Security licences?
Trend's licensing FAQ says the seat count is based on the email addresses registered to a domain, not on mailboxes, and each domain needs at least one licence. In Vision One, Cloud Email Gateway Protection counts active accounts or addresses based on mail sent or received in the past 30 days. iBlockSpam charges per domain, with unlimited mailboxes and aliases.
Is TrendAI Email Security the same product as Cloud App Security?
No. Email Security is a gateway: your MX record points to Trend and mail is filtered before it reaches your server. Cloud App Security, which Vision One offers as Cloud Email and Collaboration Protection, connects to Microsoft 365 or Gmail by API, or inline without an MX change, and scans mail at the mailbox. iBlockSpam is a gateway, like Email Security.
Which holds mail longer during an outage, Trend or iBlockSpam?
Trend does. Its FAQ says that if your mail server is unavailable, your message stream is queued for up to ten days, and Email Continuity on the Advanced licence adds a standby email system. iBlockSpam spools inbound mail for up to 5 days and delivers it when your server is back. If outages longer than five days worry you, that matters.
Can I test Trend Micro Email Security before buying it?
Yes. Trend's FAQ says you can try Email Security on a limited number of addresses and recommends a test domain, and its free-trial page offers 30 days of the TrendAI Vision One platform after a short form. iBlockSpam has no free trial; a domain's first annual subscription has a 30-day money-back guarantee instead.
Related guides
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