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Azure Functions vs Keil MDK

Azure Functions logo

Azure Functions

Cloud

Event-driven serverless compute on Azure

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: Azure Functions consumption plan free grant is capped at 1 million executions and 400,000 GB-seconds of resource consumption per month per subscription, billed per GB-second beyond that; 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 Azure Functions and Keil MDK actually diverge.

Attributes where Azure Functions and Keil MDK differ
AttributeAzure FunctionsKeil MDK
Pricing modelusage-basedfreemium
CategoryCloudDeveloper 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.

Azure Functions

  • Event-driven computingnot Keil MDK
  • Serverless application backendnot Keil MDK
  • Scalable API endpointsnot Keil MDK

Keil MDK

  • Embedded software developmentnot Azure Functions
  • ARM microcontroller programmingnot Azure Functions
  • Professional development environmentsnot Azure Functions

Where each one falls short

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

Azure Functions

  • Consumption plan free grant is capped at 1 million executions and 400,000 GB-seconds of resource consumption per month per subscription, billed per GB-second beyond that
  • The newer Flex Consumption plan's free grant is smaller still, at 250,000 executions and 100,000 GB-seconds per month
  • Premium plan avoids per-execution charges but bills continuously for allocated core seconds and memory regardless of invocation volume
  • Memory is rounded up to the nearest 128 MB and execution time to the nearest 1 ms for billing, so small overages round upward

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

Azure Functions

Free
  • Consumption Plan$null/month
    • 1 million requests free monthly
    • 400,000 GB-seconds free monthly
    • Billed per second and executions
  • Flex Consumption Plan$null/month
    • 250,000 executions free monthly
    • 100,000 GB-seconds free monthly
    • Event-driven scaling
  • Premium Plan$null/month
    • No execution charges
    • At least one instance required
    • Includes automatic scaling and VNET access

Keil MDK

Free

No published plan breakdown. See the Keil MDK review.

Which should you pick?

Choose Azure Functions if

  • You want to start without paying.
Azure Functions review

Choose Keil MDK if

  • You want to start without paying.
Keil MDK review

Questions people ask

Is Azure Functions or Keil MDK better?
Neither clearly leads. Azure Functions 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, Azure Functions or Keil MDK?
Azure Functions starts at Free and Keil MDK at Free.
Does Azure Functions or Keil MDK run on more platforms?
Both run on Web, so platform support will not decide this one for you.
Can I use Azure Functions for free?
Both have a free tier, so you can try either at no cost before committing.
What is Azure Functions best used for?
Azure Functions is most often used for event-driven computing, serverless application backend, scalable api endpoints. Of those, event-driven computing and serverless application backend are not what Keil MDK is typically brought in for.

Answered from the vendors’ own pages

Azure Functions: Does Azure Functions have a free tier?

Yes, Azure Functions includes a monthly free grant of 1 million requests and 400,000 GB-seconds on the Consumption Plan, or 250,000 executions and 100,000 GB-seconds on Flex Consumption.

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
Azure Functions: What is Azure Functions' pricing model?

Azure Functions uses usage-based pricing. Consumption plans charge per second of resource consumption and per execution, measured in gigabyte-seconds and rounded to the nearest 128 MB.

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
Azure Functions: What is the minimum execution time for Azure Functions?

The minimum execution time is 100 milliseconds on Consumption plans. Premium plans charge based on core seconds and allocated memory.

Source
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