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Cybersecurity · head to head

Cisco Duo vs Keil MDK

Cisco Duo logo

Cisco Duo

Cybersecurity

Trusted access for all users, all devices

From
Free
Free plan
Yes
Full reviewWebsite
Keil MDK logo

Keil MDK

Developer Tools

Microcontroller Development Kit for Arm-based devices

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: Cisco Duo free tier limited to 10 users maximum; Keil MDK pricing for Essential and Professional subscriptions not disclosed on primary site
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Cisco Duo and Keil MDK actually diverge.

Attributes where Cisco Duo and Keil MDK differ
AttributeCisco DuoKeil MDK
Pricing modelsubscriptionfreemium
CategoryCybersecurityDeveloper Tools

Identical on both: starting price (Free), free tier (Yes), platforms (Web), user rating (Not yet rated).

What people use each for

The jobs each tool is most often brought in to do.

Cisco Duo

  • Eliminating phishing with passwordless authnot Keil MDK
  • Implementing zero trust with device trustnot Keil MDK
  • Protecting sessions from hijacking and theftnot Keil MDK
  • Managing compliance for regulated industriesnot Keil MDK

Keil MDK

  • Embedded software developmentnot Cisco Duo
  • ARM microcontroller programmingnot Cisco Duo
  • Professional development environmentsnot Cisco Duo

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Cisco Duo

  • Free tier limited to 10 users maximum
  • Licenses must be purchased in 10-user increments (under 100 users) or 25-user increments (100+ users)
  • Pricing is per-user per-month with minimum purchase increments

Keil MDK

  • Pricing for Essential and Professional subscriptions not disclosed on primary site
  • Customers must contact Arm Developer Tools store for subscription rates

Pricing, plan by plan

Cisco Duo

Free
  • FreeFree
    • Multi-factor authentication (MFA)
    • Seamless integrations
    • Authenticator app
  • Essentials$3/month
    • All Free features
    • Duo Directory
    • Phishing-resistant MFA
  • Advantage$6/month
    • All Essentials features
    • Identity intelligence
    • Cisco Identity Intelligence (ISPM, ITDR)
  • Premier$9/month
    • All Advantage features
    • Complete device trust
    • VPN-less remote access

Keil MDK

Free

No published plan breakdown. See the Keil MDK review.

Which should you pick?

Choose Cisco Duo if

  • You want to start without paying.
Cisco Duo review

Choose Keil MDK if

  • You want to start without paying.
Keil MDK review

Questions people ask

Is Cisco Duo or Keil MDK better?
Neither clearly leads. Cisco Duo starts at Free and Keil MDK at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cisco Duo or Keil MDK?
Cisco Duo starts at Free and Keil MDK at Free.
Does Cisco Duo or Keil MDK run on more platforms?
Both run on Web, so platform support will not decide this one for you.
Can I use Cisco Duo for free?
Both have a free tier, so you can try either at no cost before committing.
What is Cisco Duo best used for?
Cisco Duo is most often used for eliminating phishing with passwordless auth, implementing zero trust with device trust, protecting sessions from hijacking and theft, managing compliance for regulated industries. Of those, eliminating phishing with passwordless auth and implementing zero trust with device trust are not what Keil MDK is typically brought in for.

Answered from the vendors’ own pages

Cisco Duo: How much does Cisco Duo cost?

Cisco Duo Free is $0/user/month (up to 10 users). Paid plans start at $3/user/month (Essentials), $6/user/month (Advantage), and $9/user/month (Premier). Billing is per-user per-month.

Source
Keil MDK: Does Keil MDK have a free version?

Yes, Keil MDK Community Edition is free for non-commercial projects. Essential and Professional editions are available as monthly or annual subscriptions.

Source
Cisco Duo: Is Cisco Duo free to try?

Yes, Duo Free offers multi-factor authentication and seamless integrations at $0/user/month for up to 10 users.

Source
Keil MDK: How much do Keil MDK paid editions cost?

Specific pricing for Essential and Professional editions is not published on the main site. Rates are available from the Arm Developer Tools store or by contacting Arm sales.

Source
Cisco Duo: What is the minimum purchase for Cisco Duo?

Organizations must buy licenses in 10-user increments for under 100 users, or 25-user increments for 100 or more users. Plans are modifiable at any time.

Source
Cisco Duo: What does the Advantage plan add over Essentials?

Advantage ($6/user/month) adds identity intelligence, Cisco Identity Intelligence (ISPM, ITDR), Duo Passport, session theft protection, Active Directory Defense, and risk-based authentication.

Source
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