Why startups buy EDR
Startups under fifty employees rarely face the threat model that justifies EDR on detection-coverage grounds alone. The realistic attacker against a typical fifty-person startup is opportunistic ransomware and credential phishing, not advanced persistent threats requiring deep endpoint telemetry. Modern next- generation antivirus with strong email security and managed identity already covers the vast majority of opportunistic attack patterns at this scale.
What forces startup EDR procurement in 2026 is almost always external. Three forcing functions dominate. SOC 2 Type II audits in flight as a precondition to enterprise customer wins. Cyber insurance underwriters requiring EDR as a baseline control for policy issuance or renewal. Enterprise customer vendor security questionnaires requiring named EDR (or specifying an acceptable list). Each of these makes EDR effectively mandatory regardless of internal threat-model assessment.
That changes the spec sheet. A startup buying EDR for compliance reasons needs the cheapest defensible posture that satisfies the auditor or carrier, not the most capable detection technology. The honest answer for most pre-Series B startups is the EDR product that is already included in their Microsoft 365 licence, configured correctly and documented for the audit. Anything beyond that is over-investment for the threat model.
The Microsoft 365 included-EDR play
Microsoft Defender for Endpoint Plan 1 is included with Microsoft 365 E3 and most Business Premium SKUs at no extra incremental cost. Plan 2 (the more capable tier with full advanced threat protection, automated investigation and response, threat-and-vulnerability management, and the deeper telemetry) is included with Microsoft 365 E5 or available as a standalone purchase.
For a startup that already pays for Microsoft 365 Business Premium (a common SKU for cloud-native startups because it includes Office, Teams, Intune device management, and Defender for Office), Plan 1 is genuinely free incremental cost. The marginal financial decision is between turning on what you already pay for versus not turning it on. Turning it on, configured correctly with attack-surface-reduction rules enabled and auto-isolation on, satisfies most auditor requirements for SOC 2 Type II endpoint detection-and- response controls.
The configuration step is non-trivial but well-documented. The Microsoft Secure Score, accessible from the Microsoft 365 admin centre, gives a baseline of how well-configured your tenant is. A startup with a Secure Score above 80 percent and Defender for Endpoint Plan 1 configured to auto-isolate on high-confidence detections has a defensible posture that costs no incremental dollars beyond the Microsoft 365 licence already in place.
Free-tier traps to avoid
Three structural traps catch startups optimising for headline-zero EDR cost.
Trap one: open-source EDR without engineering capacity. Wazuh and Velociraptor are genuinely capable open-source EDR projects, free as software, used in production by some sophisticated organisations. They are not free in operating cost. A Wazuh deployment requires a security engineer to operate, tune, maintain, and respond to alerts. For a startup with no dedicated security headcount, the implicit cost of trying to run open-source EDR is the senior engineer who is now spending 20 percent of their time on it instead of building product. That is not a saving.
Trap two: SMB-tier free plans up to ten or twenty endpoints. Several commercial EDR vendors offer free tiers for very small deployments as marketing on-ramps. The free tier is usually feature-stripped (no managed threat hunting, no premium telemetry retention, often no support beyond community forums). When the startup grows past the free-tier endpoint cap, the upgrade pricing is rarely competitive with what the same vendor would offer to a customer who started on a paid tier from day one. The free tier is a marketing on-ramp, not a sustainable posture.
Trap three: assuming consumer antivirus satisfies SOC 2. Consumer antivirus products and even some small-business antivirus products do not provide the endpoint telemetry, detection logging, and response capability that SOC 2 Type II auditors look for. The auditor question is not whether you have antivirus; it is whether you have endpoint detection, response, logging, and documented procedures. Cheap consumer-grade antivirus does not pass that bar. Microsoft Defender for Endpoint Plan 1, properly configured, does.
The pre-Series B posture
For a startup with under 100 employees, no dedicated security headcount, and a SOC 2 Type II audit in flight or upcoming, the defensible posture is straightforward. Microsoft 365 Business Premium provides the licence base. Defender for Endpoint Plan 1 is enabled, configured to auto-isolate on high-confidence detections, with attack-surface-reduction rules turned on. Alerts route to a monitored Slack or Teams channel that engineering on-call sees. A documented incident-response procedure exists and has been tabletop-tested at least once. The total incremental cost is zero (the licence is already paid) plus roughly a week of one engineer's time to configure and document.
That posture is cheap, defensible to auditors, and adequate for the typical pre-Series B startup threat model. It will not stop a sophisticated targeted attack, but a sophisticated targeted attacker is not the realistic adversary at this scale. The realistic adversary is opportunistic phishing leading to credential compromise leading to ransomware, and the Microsoft 365 stack with Defender for Endpoint plus Defender for Office configured correctly genuinely covers the realistic attack patterns at acceptable cost.
When to graduate to a paid mid-market tier
Three signals that point to graduating off the included-tier posture toward a paid mid-market EDR product.
Signal one: passing the 100-employee mark. The included-tier feature set starts to feel thin around 100 employees, particularly around managed threat hunting, identity protection deeper than password-stuffing detection, and the sophistication of automated investigation and response. The transition point is usually felt internally before it is felt externally; the security team starts wishing for capability the included tier does not provide.
Signal two: enterprise customer requirement. Some enterprise vendor security questionnaires specify acceptable EDR products by name. If a deal-breaking customer requires an EDR not on the Microsoft platform, the upgrade is forced regardless of internal preference. The cost of the upgrade is rarely material against the value of the customer win.
Signal three: post-incident gap exposure. If the startup survives a security incident and the post-mortem identifies a gap that the included tier could not have closed, the upgrade discussion shifts from procurement to risk management and typically wins. This is the most expensive way to learn you needed more, but it is also the most decisive forcing function.
The cost step from Microsoft 365 included to a paid mid-market tier is typically $5 to $10 per endpoint per month incremental, working out to $5,000 to $10,000 per year per 100 endpoints. That is generally affordable past Series A and easily defensible against a single enterprise customer win or a documented post-incident requirement.
Startup EDR procurement playbook
- Identify the actual forcing function (SOC 2 audit, customer requirement, insurance, post-incident). That determines the spec sheet.
- Confirm what is already included in your Microsoft 365 contract. Plan 1 is in many SKUs at no extra cost; turning it on is the cheapest defensible posture.
- If Microsoft is not the platform of choice for organisational reasons, evaluate the per-endpoint market with the auditor or customer requirement in hand, not as a generic EDR shopping exercise.
- Document the incident-response procedure and tabletop-test it. Auditors look for procedure and evidence of testing as much as for the technology.
- Set a reassessment trigger (employee count, customer mix, post-incident review) that forces a re- evaluation rather than letting the initial decision drift forward indefinitely.