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Lambda (AWS Serverless) vs Keycloak

Lambda (AWS Serverless) logo

Lambda (AWS Serverless)

Cloud

Run code without thinking about servers

From
Free
Free plan
Yes
Full reviewWebsite
Keycloak logo

Keycloak

Developer Tools

Open-source identity and access management server.

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: Lambda (AWS Serverless) billed on two axes at once, $0.20 per million requests plus $0.0000166667 per GB-second of duration, so memory settings change the bill as much as traffic does; Keycloak requires self-hosted deployment and operational expertise to install, configure and maintain
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Lambda (AWS Serverless) and Keycloak actually diverge.

Attributes where Lambda (AWS Serverless) and Keycloak differ
AttributeLambda (AWS Serverless)Keycloak
Pricing modelusage-basedopen-source
PlatformsWeb, ApiSelf-hosted, Docker, Kubernetes, Linux, Windows, API
CategoryCloudDeveloper Tools
Founded2014Unknown

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

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Lambda (AWS Serverless)

  • Function-as-a-Service
  • Event-driven execution
  • Auto-scaling
  • Pay-per-use
  • Multiple languages
  • Concurrency limits
  • Dead Letter Queues
  • Environment variables

Only in Keycloak

Nothing recorded that Lambda (AWS Serverless) does not also cover.

What people use each for

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

Lambda (AWS Serverless)

  • Event-driven functions without managing serversnot Keycloak
  • API backends behind API Gatewaynot Keycloak
  • Processing S3, DynamoDB, SQS and Kinesis eventsnot Keycloak
  • Scheduled jobs without a always-on instancenot Keycloak
  • Edge compute through Lambda@Edgenot Keycloak

Keycloak

  • Organisations requiring self-hosted identity infrastructure for compliance or data residencynot Lambda (AWS Serverless)
  • Companies with existing LDAP/Active Directory systems needing federated authenticationnot Lambda (AWS Serverless)
  • Open-source projects and communities requiring free IAM without licensing costsnot Lambda (AWS Serverless)
  • Enterprises building custom identity workflows requiring fine-grained authorisationnot Lambda (AWS Serverless)
  • Teams with sufficient operational expertise to manage infrastructurenot Lambda (AWS Serverless)

Where each one falls short

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

Lambda (AWS Serverless)

  • Billed on two axes at once, $0.20 per million requests plus $0.0000166667 per GB-second of duration, so memory settings change the bill as much as traffic does
  • Provisioned concurrency, used to avoid cold starts, is charged separately at $0.0000041667 per GB-second whether or not the function runs
  • Ephemeral storage beyond the included 512 MB is metered
  • Lambda@Edge costs $0.60 per million requests, three times the standard request rate
  • VPC use and cross-region data transfer carry EC2 charges on top

Keycloak

  • Requires self-hosted deployment and operational expertise to install, configure and maintain
  • No managed cloud option provided by Red Hat; organisations must operate infrastructure themselves or use third-party distributions
  • Clustering and high-availability configurations require additional operational knowledge
  • Community support only; commercial support requires third-party vendors or distributions

Pricing, plan by plan

Lambda (AWS Serverless)

Free
  • Free TierFree
    • 1M free requests/month
    • 400,000 GB-seconds/month
    • Always free

Keycloak

Free
  • Open-sourceFree
    • Full platform functionality
    • Self-hosted deployment
    • Community support

Which should you pick?

Choose Lambda (AWS Serverless) if

  • You need function-as-a-service.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want event-driven execution.
Lambda (AWS Serverless) review

Choose Keycloak if

  • You want to start without paying.
  • You work on Self-hosted, Docker, Kubernetes, Linux, Windows, API.
Keycloak review

Questions people ask

Is Lambda (AWS Serverless) or Keycloak better?
Neither clearly leads. Lambda (AWS Serverless) starts at Free and Keycloak at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Lambda (AWS Serverless) or Keycloak?
Lambda (AWS Serverless) starts at Free and Keycloak at Free.
Does Lambda (AWS Serverless) or Keycloak run on more platforms?
Lambda (AWS Serverless) runs on Web, Api. Keycloak runs on Self-hosted, Docker, Kubernetes, Linux, Windows, API.
Can I use Lambda (AWS Serverless) for free?
Both have a free tier, so you can try either at no cost before committing.
What is Lambda (AWS Serverless) best used for?
Lambda (AWS Serverless) is most often used for event-driven functions without managing servers, api backends behind api gateway, processing s3, dynamodb, sqs and kinesis events, scheduled jobs without a always-on instance. Of those, event-driven functions without managing servers and api backends behind api gateway are not what Keycloak is typically brought in for.
What can Lambda (AWS Serverless) do that Keycloak cannot?
Lambda (AWS Serverless) covers Function-as-a-Service, Event-driven execution, Auto-scaling, Pay-per-use.

Answered from the vendors’ own pages

Lambda (AWS Serverless): Is there a free tier for AWS Lambda?

Yes. AWS Lambda offers a free tier including 1 million requests per month, 400,000 GB-seconds per month, and 100 GB monthly response streaming.

Source
Keycloak: What protocols does Keycloak support?

Keycloak supports OpenID Connect, OAuth 2.0 and SAML 2.0 protocols for authentication and authorisation.

Source
Lambda (AWS Serverless): How is AWS Lambda charged?

Lambda charges $0.20 per million requests. Duration charges are $0.0000166667 per GB-second for x86 (up to 6 billion GB-seconds/month in US East Ohio with tiered pricing). Ephemeral storage over the included 512 MB costs $0.0000000309 per GB-second. Provisioned Concurrency costs $0.0000041667 per GB-second with a 5-minute minimum.

Source
Keycloak: Can Keycloak integrate with existing user directories?

Yes. Keycloak supports user federation with LDAP and Active Directory systems, allowing organisations to leverage existing user directories.

Source
Lambda (AWS Serverless): What are Lambda Durable Functions pricing?

Lambda Durable Functions include operations at $8.00 per million (start execution, steps, waits). Data written costs $0.25 per GB. Data retention is $0.15 per GB-month with configurable 1-90 day retention (default 14 days).

Source
Keycloak: Is Keycloak free?

Yes. Keycloak is fully open-source and free to deploy and use. No licensing fees are required.

Source
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