TrustLayer as a Mimecast alternative.
If you're a UK organisation of 100 to 5,000 people on Microsoft 365, running email security and archiving with a small IT team, this is a fair comparison of the two.
One difference up front: Mimecast sells you email security. TrustLayer is a platform with four layers, and email is one of them. If your Mimecast estate also includes Cloud Web Security, that matters more than usual this year.
Three real differences.
Mimecast is a capable email security product. Most of what it does, we do. Comparison tables that suggest otherwise are wasting your time. So here is where the competition separates:
Mimecast's Governance, Compliance and Insight Suite runs a seven-year retention default, with extensions available on request, inside an account-level maximum retention setting.
TrustLayer's Compliant Email Archive retains indefinitely by default, and you can configure it shorter if your policy says so. No ceiling to request an increase to. Changes to retention need a second approver with the Data Guardian role, a four-eyes process, and any access to a message by someone who wasn't a party to it is audited in real time.
Leaving an archiving vendor is the hard part, and most comparison pages pretend it isn't. We run a managed migration through a specialist partner: scoped, assessed and reported before anything moves, and run in parallel with the old archive so nothing stops.
The first conversation covers your volumes, your retention obligations and who does what, so the plan is real before you commit to anything.
Mimecast publishes no pricing. Every plan tier ends in "contact sales".
TrustLayer publishes indicative per-user pricing on the site. Mail is from £2.70 per user per month as the Email Advanced bundle, at 750+ users, billed annually. Your BT account team, MSP or reseller confirms the number for your headcount.
Most rows tie. These are the ones that don't.
Both treat archiving as an add-on, both cover out-of-hours, and both run awareness training as a separate product. Mimecast wins on continuity. The rest of the table is where the decision sits.
Where Mimecast is the better choice.
Three moving parts. None of them touch each other.
Microsoft 365 Transport Rules and Connectors, or traditional MX routing. Pick either, switch with a wizard. Same quarantine engine and protection layers on both paths.
Managed migration as above. You can run archiving in parallel during cutover, so nothing stops while the historic data moves.
Pushed through Intune, Jamf or any MDM, or a link for the stragglers. Windows and macOS. No proxy to stand up, so it doesn't interact with the mail cutover at all.
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