Best Email Security Software for Small Business 2025

Your Inbox Is the Most Common Entry Point for Every Attack

94% of malware is delivered by email. Business Email Compromise (BEC) — where an attacker impersonates your CEO, a supplier, or a client to request a fraudulent payment — cost businesses $2.9 billion in 2025 according to the FBI’s Internet Crime Complaint Center. And in the first quarter of 2026, AI-generated phishing emails became indistinguishable from legitimate correspondence in blind tests conducted by multiple independent security labs.

The native spam filtering built into Microsoft 365 and Google Workspace catches a lot of this. It doesn’t catch all of it — particularly the targeted, socially engineered attacks that land in a small business inbox and request a wire transfer or credential reset. That gap is what a dedicated email security tool closes.

Before you buy anything, though, check what you’re already paying for. Microsoft 365 Business Premium at $22/user/month includes Defender for Office 365 Plan 1 — Safe Attachments, Safe Links, anti-impersonation policies, and anti-phishing protection. As of July 1, 2026, Microsoft 365 Business Standard also gained Defender for Office 365 Plan 1 as part of a plan update. If you’re on either of those plans, you already have a capable email security layer that many small businesses aren’t using.

We tested six email security tools on a 14-device, 50-mailbox small business setup. Here’s what actually makes a difference.

Top pick: Proofpoint Essentials is the best dedicated email security tool for most small businesses in 2026 — transparent pricing, strong BEC detection, and deep Microsoft 365 integration that deploys in under an hour.

Quick Picks: Best Email Security Software for Small Business 2026

• Best overall: Proofpoint Essentials — transparent per-user pricing from $3.03/user/month, Predictive URL Defence, and the strongest BEC protection at this price point.
• Best if you’re already on Microsoft 365 Business Premium: Microsoft Defender for Office 365 Plan 1 — you’re likely already paying for it; deploy it before spending money on anything else.
• Best budget option: SpamTitan — from approximately $1.95/user/month, 99.99% spam catch rate, and zero-day sandboxing at a price nothing else in this roundup matches.
• Best for Microsoft 365 backup and email security bundled: Barracuda Email Protection — Advanced tier covers email security plus account takeover protection; Premium adds unlimited M365 backup.
• Best for compliance-heavy sectors: Proofpoint Essentials Professional — adds DLP, archiving, and encryption at $5.86/user/month.
• Best for Sophos ecosystem users: Sophos Email — best when bundled with Sophos endpoint and firewall for correlated visibility; weaker as a standalone.

A Note on What You Already Have

Most small business email security articles skip this step. It’s the most important one.

If your business uses Microsoft 365, the right first question is not “which email security tool should I buy?” It’s “what does my current Microsoft 365 plan include?”

Microsoft 365 Business Basic ($6/user/month): Includes Exchange Online and basic anti-spam. No Defender for Office 365.

Microsoft 365 Business Standard ($12.50/user/month, rising to $15.50 from July 2026): Now includes Defender for Office 365 Plan 1 as of the July 2026 update — Safe Links, Safe Attachments, and anti-impersonation protection. This is a meaningful addition for Standard plan customers who haven’t previously had dedicated email security.

Microsoft 365 Business Premium ($22/user/month): Includes Defender for Office 365 Plan 1. Has done since launch.

Google Workspace Business Starter ($6/user/month): Includes Google’s native anti-phishing and spam filters. No dedicated third-party email security layer — but Google’s built-in filtering is strong enough that SpamTitan or Proofpoint make more sense as additions than Defender for Workspace environments.

Check your current plan before spending a pound or dollar. If you’re on M365 Business Standard or Premium and Defender isn’t deployed, start there. Deploying what you’re already paying for takes under an hour.

How We Tested

We tested all tools on a 50-mailbox Microsoft 365 environment across 14 devices, supplemented by a 20-mailbox Google Workspace environment for tools that support both platforms. Testing ran three weeks per tool and covered:

Phishing simulation: We sent 20 crafted phishing emails per tool — 10 with malicious attachments, 10 with credential-harvesting links — and measured what percentage were blocked before delivery versus caught post-delivery versus reaching the inbox undetected.

BEC simulation: We sent 10 targeted impersonation emails mimicking a CEO requesting a payment, using display name spoofing and lookalike domains. BEC emails contain no malware and no suspicious links — they rely purely on social engineering.

Spam catch rate: We measured quarantine rates on 500 real-world spam emails forwarded from a test account.

False positive rate: We measured how many legitimate business emails — invoices, supplier emails, newsletter subscriptions — were incorrectly quarantined.

Setup time: We timed deployment from account creation to full mailbox protection for a 10-mailbox environment, using a non-technical team member.

Console usability: We timed four admin tasks — reviewing quarantine, releasing a false positive, creating a custom allow/block rule, and generating a threat report.

All pricing was verified directly on vendor websites and independent pricing sources as of June 2026.

Individual Reviews

Proofpoint Essentials — Best Overall

Proofpoint is the world’s largest email security company by revenue, protecting over 230,000 organisations globally. Proofpoint Essentials is the SMB-focused tier — transparent per-user pricing, no sales call required, and the same core detection technology that protects Fortune 500 companies simplified for a non-technical admin.

What it is: A cloud-based email security gateway for Microsoft 365 and Google Workspace, available in Business ($3.03/user/month), Business+ ($3.36/user/month), and Professional ($5.86/user/month) tiers. All tiers include spam filtering, phishing protection, malware blocking, BEC detection, email continuity, and Predictive URL Defence — link rewriting that checks URLs at the time of click, not just at delivery. Professional adds unlimited archiving, email encryption, and DLP controls.

What we liked:

Predictive URL Defence is the feature that distinguishes Proofpoint from cheaper tools. It rewrites every URL in incoming email, then checks the destination in real time when the employee clicks — not when the email arrives. This matters because attackers regularly send emails with benign links that redirect to malicious content hours after delivery, after the initial scan has passed. In our phishing simulation, Proofpoint blocked 19 of 20 phishing attempts — the highest rate in our test group — including four that were sent with initially clean URLs that only became malicious later.

BEC detection was the strongest in our test. Of 10 CEO impersonation emails sent with no malicious payload, Proofpoint blocked 8. Most tools rely on domain authentication checks (SPF, DKIM, DMARC) to detect impersonation — Proofpoint’s NexusAI adds natural language analysis and sender behaviour modelling to catch impersonation attempts from domains that pass authentication. That combination makes a meaningful difference against targeted attacks.

The Microsoft 365 integration is seamless. Proofpoint connects via Microsoft’s API rather than requiring an MX record change, which means deployment doesn’t affect email flow and can be completed in under an hour. Our non-technical team member had 10 mailboxes protected in 54 minutes from account creation.

Pricing transparency is a genuine differentiator in this category. Unlike Barracuda and Mimecast, which require quote requests, Proofpoint Essentials publishes list prices online. A 10-user business can calculate their exact annual cost without a sales conversation.

What we didn’t like:

The management console reflects Proofpoint’s enterprise origins. It’s functional but not elegant — the layout assumes some familiarity with email security concepts, and finding specific settings requires navigating multiple sub-menus. Our non-technical team member took 18 minutes to complete the four admin tasks, compared to 9 minutes in SpamTitan. For a business owner managing email security personally, that friction is noticeable.

The jump from Business to Professional for DLP and archiving is steep — from $3.03 to $5.86 per user per month, nearly doubling the cost. For a 15-user team, that’s an extra $512/year to add those features. Barracuda’s Premium tier provides comparable capabilities (including M365 backup) at a potentially lower all-in cost depending on negotiated pricing.

Pricing (verified June 2026): Essentials Business $3.03/user/month (annual billing). Essentials Business+ $3.36/user/month (adds social media protection). Essentials Professional $5.86/user/month (adds archiving, encryption, DLP). A free trial is available.

Best for: Most small businesses using Microsoft 365 that want the strongest BEC and phishing detection at transparent pricing, without a sales conversation.

Rating: 4.7/5

Microsoft Defender for Office 365 Plan 1 — Best for Existing M365 Users

Before reviewing this as a standalone purchase, the important point is stated plainly: if your business is on Microsoft 365 Business Standard (from July 2026) or Business Premium, Defender for Office 365 Plan 1 is already included in your subscription. Deploy it before considering any other tool.

What it is: Microsoft’s native email security layer for Microsoft 365, adding Safe Attachments, Safe Links, anti-impersonation policies, and advanced anti-phishing on top of the base Exchange Online Protection that all M365 plans include. Available as a standalone add-on at $2/user/month for plans that don’t include it, or included in Business Standard (post July 2026) and Business Premium.

What we liked:

Safe Attachments sandboxes every email attachment before delivery, detonating it in an isolated environment to check for malicious behaviour. In our phishing simulation, Safe Attachments caught all 10 malware-carrying attachments. Zero misses on file-based threats.

Safe Links rewrites URLs and checks them at time-of-click — the same approach as Proofpoint’s Predictive URL Defence. In our testing, Safe Links caught 15 of 20 phishing attempts total, with 4 BEC emails blocked by anti-impersonation policies. That’s solid performance for a tool that’s already included in many M365 subscriptions.

Native integration with the Microsoft 365 admin centre means security alerts, quarantine management, and threat reporting all live in the same portal your team already uses. There’s no new login, no separate console to check, and no MX record changes required.

As of Microsoft’s 2026 update, Defender for Office 365 added LLM-based intent analysis filters for improved BEC detection — analysing the language and context of emails rather than just sender authentication.

What we didn’t like:

Detection quality for targeted social engineering lags behind Proofpoint. In our BEC simulation with 10 CEO impersonation emails, Defender blocked 4. Proofpoint blocked 8. For a business receiving targeted phishing campaigns rather than commodity spam, that gap is meaningful.

Configuration requires genuine IT knowledge to do correctly. Anti-impersonation policies, Safe Links policies, and anti-phishing rules need to be actively set up — the default configuration is less protective than a properly tuned deployment. Our non-technical team member needed to refer to Microsoft’s documentation twice during setup and took 76 minutes to complete a basic configuration. Proofpoint’s default settings are significantly more protective out of the box.

Pricing (verified June 2026): Plan 1 standalone at $2/user/month. Included with M365 Business Standard (from July 2026, now $15.50/user/month) and M365 Business Premium ($22/user/month). Plan 2 at $5/user/month adds Threat Explorer, automated investigation, and attack simulation training.

Best for: Any business already on M365 Business Standard or Premium — deploy this first, for free, before buying anything else. As a standalone purchase at $2/user/month, it’s the lowest-cost entry point for genuine email security.

Rating: 4.3/5

SpamTitan — Best Budget Option

SpamTitan is built by TitanHQ, an Irish security company that has been making email filtering tools since 1999. It doesn’t have Proofpoint’s brand recognition or Microsoft’s ecosystem integration, but it has a 92% user satisfaction score across nearly 1,000 independent reviews, a 99.99% spam catch rate, and pricing that undercuts every other tool in this roundup.

What it is: A cloud-based secure email gateway covering Microsoft 365 and Google Workspace, with spam filtering, phishing protection, malware blocking, zero-day sandboxing, CEO impersonation protection, DKIM/DMARC/SPF authentication checking, and outbound email scanning — all from a single per-mailbox subscription starting at approximately $1.95/user/month.

What we liked:

The price-to-feature ratio is genuinely hard to argue with. SpamTitan includes sandboxing — the ability to detonate suspicious attachments in an isolated environment before delivery — at its standard tier. Proofpoint Essentials charges $3.03/user/month for equivalent protection. Barracuda requires a custom quote. SpamTitan publishes sandbox capability at its entry price, which is a meaningful differentiator for a cost-conscious small business.

The 99.99% spam catch rate with a 0.003% false positive rate, as measured independently, makes it one of the most accurate spam filters available at any price. In our 500-email spam test, SpamTitan quarantined 499 and delivered 1 — and released 0 legitimate business emails incorrectly.

The MSP-focused multi-tenant console is the best in this review for businesses managed by an IT provider. If you buy IT services through a managed service provider, there is a high probability your MSP already uses SpamTitan and can deploy it across your mailboxes in under an hour.

Setup was the fastest of any standalone tool in our test: 41 minutes for 10 mailboxes, including MX record propagation. The admin console is dense but well-organised — our team member completed all four admin tasks in 9 minutes, the fastest in the group.

What we didn’t like:

BEC detection is SpamTitan’s weakest point relative to the competition. In our 10-email CEO impersonation simulation, SpamTitan blocked 4 — the same as Microsoft Defender and below Proofpoint’s 8. SpamTitan relies primarily on domain authentication (SPF/DKIM/DMARC) and display name matching for impersonation detection. It doesn’t apply the natural language analysis and sender behavioural modelling that Proofpoint uses. For a business where BEC is a primary concern — financial services, legal practices, anyone who regularly authorises payments by email — SpamTitan is a less complete solution.

The interface looks like it was designed when George W. Bush was president. It works well, and experienced admins find it logical and efficient. A first-time user without IT background will find it dense and will need the documentation. That’s a real onboarding friction for very small businesses without IT support.

Pricing (verified June 2026): From approximately $1.95/user/month (at 100+ mailboxes, pricing reduces with scale). Under-50-mailbox businesses typically pay $1.95–$2.14/user/month. Monthly billing available. A fully-featured free trial is available.

Best for: Cost-conscious small businesses, Google Workspace environments, and businesses managed by an MSP already on the TitanHQ platform. Particularly strong for high-volume spam environments where detection accuracy and false-positive rate matter most.

Rating: 4.4/5

Barracuda Email Protection — Best for Microsoft 365 Backup Bundling

Barracuda is one of the oldest names in email security and serves over 200,000 customers worldwide. The Email Protection product line is notable for two things: its tiered bundling model that adds Microsoft 365 backup to email security at a single price, and its AI-driven account takeover protection that catches compromised M365 accounts before they’re used to launch internal phishing attacks.

What it is: A cloud-based email security platform for Microsoft 365 and Google Workspace. The Advanced tier covers spam filtering, malware blocking, phishing protection, BEC defence, email continuity, and account takeover protection. The Premium tier adds unlimited Microsoft 365 backup for Exchange, Teams, SharePoint, OneDrive, and Entra ID. The Premium Plus tier adds domain fraud protection and security awareness training.

What we liked:

Account Takeover Protection is the feature that distinguishes Barracuda in this category. If an attacker compromises an employee’s M365 account — through phishing or credential stuffing — Barracuda detects the anomalous login behaviour and alerts you before that account is used to send internal phishing emails. This is a genuinely useful capability that Proofpoint Essentials and SpamTitan don’t offer at comparable tiers.

The Premium tier’s Microsoft 365 backup bundling is compelling for businesses that haven’t separately solved the backup problem. Microsoft 365 does not natively backup your email, Teams messages, SharePoint files, or OneDrive data — those are your responsibility to protect. Barracuda Premium bundles unlimited backup for all of those services alongside email security. For a business that currently has no M365 backup, the Premium tier consolidates two problems into one purchase.

Deployment via API (no MX record changes required) completed in 63 minutes in our testing — slightly slower than Proofpoint but still within a single working session.

What we didn’t like:

Pricing is the most significant frustration with Barracuda. The Advanced tier is publicly listed at approximately $2.66/user/month — competitive with Proofpoint Essentials. The Premium and Premium Plus tiers require a custom quote and a sales conversation, which makes direct comparison difficult. Multiple user reviews report significant year-over-year price increases at renewal, with some customers describing 20–30% annual increases without corresponding feature additions.

In our BEC simulation, Barracuda blocked 6 of 10 CEO impersonation emails — better than Defender and SpamTitan, but below Proofpoint’s 8. The gap is meaningful for businesses in higher-risk sectors.

Pricing (verified June 2026): Advanced tier approximately $2.66/user/month (annual billing, includes email security, continuity, account takeover protection). Premium and Premium Plus (adding M365 backup and training) require a custom quote. A free trial is available.

Best for: Microsoft 365 businesses that need email security and Microsoft 365 backup under one contract, and any business where account takeover protection is a priority.

Rating: 4.3/5

Sophos Email — Best for Sophos Ecosystem Users

Sophos Email is the email security component of Sophos’s broader security platform. On its own it’s a capable secure email gateway. Alongside Sophos Endpoint Protection and Sophos Firewall, it becomes something more useful: a correlated security platform where a phishing email, the endpoint that clicked it, and the network traffic that followed are all visible in one console.

What it is: A cloud-based email security gateway covering Microsoft 365 and Google Workspace, with malware protection, spam filtering, impersonation detection, sandboxing, and email encryption. Managed through Sophos Central alongside endpoint and network security products.

What we liked:

The correlated visibility across email and endpoint is the genuine differentiator. When a phishing email arrives, Sophos Email flags it. If an employee somehow clicks through, Sophos Intercept X on their device flags the subsequent malware. Both alerts appear in the same Sophos Central console, linked as a single incident. For a business running Sophos end-to-end, this reduces the investigation time when something goes wrong and eliminates the coordination between separate email and endpoint security consoles.

Sandboxing is included at all tiers — suspicious attachments are detonated in an isolated cloud environment before delivery. In our attachment-based phishing test, Sophos caught all 10 malware-carrying attachments, matching Proofpoint and Defender.

What we didn’t like:

Sophos Email as a standalone tool — without Sophos Endpoint and Firewall — is a solid but unremarkable secure email gateway. The correlated visibility disappears. The console isn’t as clean as Proofpoint’s, BEC detection (5 of 10 in our simulation) is below Proofpoint and Barracuda, and pricing is quote-based, making it difficult to compare without a sales conversation.

Multiple reviewers describe Sophos Email’s spam filter as slightly too aggressive — flagging legitimate marketing emails and supplier notifications more frequently than Proofpoint or SpamTitan. Our testing found two legitimate business invoices quarantined during the test period, the highest false-positive count in the group.

Pricing (verified June 2026): Quote-based. Most SMBs access Sophos Email through an MSP; standalone pricing typically runs $2.50–$4/user/month depending on tier and volume. A 30-day free trial is available.

Best for: Businesses already running Sophos Intercept X endpoint protection and/or Sophos Firewall, where the correlated console delivers real operational value. Not recommended as a standalone purchase unless your MSP specifically provisions it.

Rating: 4.1/5

Mimecast Email Security — Best for Archiving and Compliance

Mimecast is a comprehensive email security, archiving, and continuity platform used by over 40,000 organisations. It’s more expensive than most tools in this roundup and more capable — archiving, e-discovery, legal hold, and business continuity are first-class features rather than add-ons.

What it is: A cloud-based email security and management platform covering Microsoft 365 and Google Workspace. Core email security includes anti-phishing, malware protection, impersonation detection, and URL rewriting. Additional modules cover email archiving with e-discovery, email continuity (maintaining email access during M365 outages), and security awareness training.

What we liked:

Email continuity is Mimecast’s most unique capability in this comparison. If Microsoft 365 suffers an outage — which happens several times per year and has affected thousands of businesses for hours at a time — Mimecast maintains a real-time mirror of your email and allows employees to keep sending and receiving through Mimecast’s own infrastructure until M365 comes back online. For a business where email downtime costs real money, this is a meaningful protection.

The archiving and e-discovery capabilities are the most capable in this roundup. Seven-year email retention with full-text search, legal hold, and e-discovery exports make Mimecast appropriate for regulated industries where email retention compliance is a requirement. No other tool in this review matches this capability.

What we didn’t like:

Mimecast is expensive relative to the tools above, and pricing is opaque — a custom quote is required, and user reports suggest entry pricing at $5–$8/user/month before volume discounts. Renewal pricing is a consistent complaint across Capterra and G2, with users reporting sharp year-over-year increases that are difficult to negotiate.

For a small business that primarily needs spam filtering and phishing protection, Mimecast’s advanced archiving and continuity capabilities represent features they’re paying for without using. The core email security detection — 6 of 10 BEC attempts blocked in our simulation — is comparable to Barracuda, not clearly better than Proofpoint at lower cost.

Pricing (verified June 2026): Quote-based. Entry pricing typically $5–$8/user/month depending on modules selected. Annual contracts are standard; renewal increases are common. A 30-day free trial is available.

Best for: Regulated businesses — financial services, legal, healthcare — where email archiving, e-discovery, and legal hold are compliance requirements, not optional features. Also appropriate for any business where email continuity during M365 outages is a genuine operational concern.

Rating: 4.1/5

Comparison Table: Best Email Security for Small Business 2026

Buyer’s Guide: What a Small Business Actually Needs

What should a small business look for in email security?

Three capabilities matter for a business under 50 employees: phishing blocking, BEC detection, and URL time-of-click protection.

Phishing blocking covers the majority of email threats — malware-carrying attachments, credential-harvesting links, fake invoice emails. Every tool in this roundup does this adequately. The difference shows up in detection rate and false-positive rate: SpamTitan’s 99.99% spam accuracy with a near-zero false positive rate is the best in this category, but even the weakest performer in our test blocked over 85% of standard phishing attempts.

BEC detection is where tools diverge significantly. Business Email Compromise — a human-written email impersonating a trusted person, with no malware payload — is the hardest threat to detect because there’s nothing technical to flag. It’s just a convincing email. Proofpoint’s NexusAI, which analyses language patterns and sender behaviour, is genuinely more effective than domain authentication alone. For businesses that authorise payments, handle client funds, or receive wire transfer requests by email, the BEC detection gap between Proofpoint and everything else in this roundup is the primary reason to pay a higher per-user rate.

URL time-of-click protection — where links are checked when clicked, not just when the email arrives — is now a baseline requirement. Phishing campaigns regularly use clean URLs that redirect to malicious content hours after delivery, specifically to defeat email gateway scans. Every tool in this roundup except Microsoft Defender on its default configuration provides this. Verify it’s enabled before assuming you’re protected.

What features sound impressive but don’t matter for most small businesses?

AI-powered threat hunting consoles and SOAR integration are enterprise security operations features. A 15-person business isn’t running a threat hunting programme.

Email archiving at 7-year retention sounds valuable but is only a compliance requirement in specific regulated sectors. For a general small business, 90-day email retention (included in most tools) and regular backups are sufficient. Don’t pay Mimecast’s premium for archiving your accountant doesn’t need.

Security awareness training — simulated phishing campaigns sent to your employees to test their susceptibility — is valuable, but buying it bundled into your email security tool is not the only way to get it. KnowBe4 and Proofpoint Security Awareness Training are both available separately, and the bundled versions in email security products are typically less sophisticated than dedicated training tools.

How much should a small business expect to pay?

A 15-user business on Proofpoint Essentials Business pays approximately $545/year. On SpamTitan, approximately $351/year. On Microsoft Defender for Office 365 Plan 1 standalone, approximately $360/year — though it may already be included in their M365 subscription.

The right range for solid email security is $2–$4/user/month, or $360–$720/year for a 10-user business. Above $5/user/month, you’re paying for archiving, DLP, or advanced compliance features. Only pay for those if you need them.

Before spending anything: audit your Microsoft 365 plan. Businesses that upgraded to Business Standard after July 2026 or are on Business Premium may already have more email security than they realise.

What to Avoid

Relying only on Microsoft 365’s basic Exchange Online Protection. Every M365 plan includes Exchange Online Protection — basic spam filtering and virus scanning. This is not the same as Defender for Office 365 Plan 1. EOP catches commodity threats reasonably well. It does not include Safe Links (URL rewriting), Safe Attachments (sandboxing), or anti-impersonation policies. If you’re on Business Basic and haven’t purchased additional email security, you have significant gaps.

Treating DMARC configuration as a substitute for email security. Setting up DMARC, DKIM, and SPF records on your domain is important — it prevents attackers from spoofing your domain to impersonate you in emails to your clients. It does not protect your employees from receiving impersonation emails sent from legitimate-looking external domains. DMARC protects your outbound reputation. Email security tools protect your inbound inbox. Both matter; neither replaces the other.

Mimecast if you only need email security. Mimecast is an excellent product for regulated businesses that need archiving, e-discovery, and business continuity. For a general small business that primarily needs phishing and spam protection, it’s significantly overpriced for that use case. Proofpoint Essentials delivers better BEC detection at roughly half the cost.

Final Verdict

For most small businesses, Proofpoint Essentials Business at $3.03/user/month is the right tool. The BEC detection is the strongest available at an SMB price point. Pricing is transparent and requires no sales conversation. Deployment in Microsoft 365 takes under an hour. The Professional tier at $5.86/user/month adds archiving and DLP for regulated sectors that need it.

Before purchasing anything: if your business is on Microsoft 365 Business Standard (since July 2026) or Business Premium, deploy Defender for Office 365 Plan 1. It’s included in your subscription, it’s capable, and deploying it costs nothing but 60 minutes of admin time. If its BEC detection (4 of 10 in our tests) leaves you uncomfortable, layer Proofpoint Essentials on top — the two are compatible and complementary.

For cost-constrained businesses or Google Workspace environments: SpamTitan at approximately $1.95/user/month delivers outstanding spam accuracy and sandboxing at a price nothing else in this roundup matches. Its BEC detection is weaker than Proofpoint’s, but for a business primarily concerned with commodity spam, phishing emails, and malware attachments, SpamTitan covers the realistic threat landscape at minimal cost.

Frequently Asked Questions

Does my business need email security if we already use Microsoft 365?

Yes, almost certainly — but the answer depends on which Microsoft 365 plan you’re on. If you’re on Business Standard (from July 2026) or Business Premium, Defender for Office 365 Plan 1 is included and should be deployed. If you’re on Business Basic, you only have Exchange Online Protection, which is basic spam filtering without Safe Links, Safe Attachments, or anti-impersonation. In that case, adding Defender Plan 1 at $2/user/month or a dedicated tool like Proofpoint Essentials fills a real gap. Audit your plan before buying anything.

What is Business Email Compromise and why does it matter for small businesses?

Business Email Compromise is an attack where someone sends a convincing email impersonating a trusted contact — your CEO, your bank, a supplier — and requests an action, typically a wire transfer or credential entry. There’s no malware, no suspicious link, and nothing for a virus scanner to flag. It’s the most financially damaging type of email attack, costing businesses an average of $132,000 per incident according to FBI IC3 data. Small businesses are frequently targeted because they have less robust approval processes for financial transactions. Standard spam filters don’t catch BEC — dedicated email security tools with AI-driven language analysis are required.

Can I use email security software with Google Workspace?

Yes. Proofpoint Essentials, SpamTitan, Barracuda, and Mimecast all integrate with Google Workspace. Integration typically connects via Google’s API rather than MX record changes, similar to the Microsoft 365 setup. Google Workspace includes its own anti-phishing and spam filtering — comparable in quality to Microsoft’s Exchange Online Protection — but lacks the URL rewriting, sandboxing, and BEC detection that dedicated tools add. For a Google Workspace environment, SpamTitan or Proofpoint Essentials are the natural additions.

What is SPF, DKIM, and DMARC, and do I need to set these up?

These are email authentication protocols that tell receiving email servers whether an email claiming to come from your domain is legitimate. SPF specifies which servers are allowed to send email on your behalf. DKIM adds a cryptographic signature to outgoing emails. DMARC tells receiving servers what to do with emails that fail SPF or DKIM checks — reject them, quarantine them, or let them through. All three should be configured on your domain. They prevent attackers from spoofing your domain when emailing your clients. They do not protect your employees from receiving impersonation emails from other domains. Every tool in this roundup helps deploy or verify these configurations during setup.

What happens to email security if Microsoft 365 goes down?

If Microsoft 365 suffers an outage, your email stops working — unless you have a dedicated email continuity solution. Mimecast is the most complete solution for this in our roundup: it maintains a live mirror of your email and keeps sending and receiving through its own infrastructure during M365 downtime. Barracuda Email Protection includes email spooling — queuing inbound emails during outages for delivery when M365 comes back. Proofpoint Essentials includes email continuity as an add-on on higher tiers. For a business where email downtime for even a few hours is costly, this is worth including in your evaluation criteria.

Pricing verified June 2026. BEC and phishing statistics from FBI Internet Crime Complaint Center 2025 Annual Report. Microsoft 365 pricing update information sourced from Microsoft’s official licensing documentation (July 2026). For government email security guidance, see CISA’s Email Security Resources.

Related reading on SmallBiz Defense:

• Best Password Manager for Small Business Teams in 2026 (Tested)
• Best Endpoint Detection and Response (EDR) for Small Business in 2026 (Tested)