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APIs · head to head

Asyncapi vs Cilium

Asyncapi logo

Asyncapi

APIs

Specification and tools for defining asynchronous APIs

From
Free
Rated
-
Full reviewWebsite
Cilium logo

Cilium

Cloud

eBPF-based networking, observability and security for Kubernetes

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Asyncapi complex to implement and debug asynchronous operations due to their non-linear and concurrent nature; Cilium requires a recent Linux kernel, which rules out older distributions and some managed environments
  • They diverge on capability: Asyncapi covers API Specification, Cilium covers eBPF datapath.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Asyncapi and Cilium actually diverge.

Attributes where Asyncapi and Cilium differ
AttributeAsyncapiCilium
Pricing modelopen-sourceOpen source, no licence fee
PlatformsWeb, CLI, IDE ExtensionsKubernetes, Linux
CategoryAPIsCloud
Founded2019Unknown

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 Asyncapi

  • API Specification
  • Code generation
  • Documentation
  • Multiple messaging protocols
  • Code generators
  • Specification support
  • Tools support
  • CLI support

Only in Cilium

  • eBPF datapath
  • Identity-based policy
  • Hubble observability
  • Sidecar-free mesh

What people use each for

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

Asyncapi

  • API Developmentnot Cilium
  • API Gatewaynot Cilium
  • API Testingnot Cilium
  • API Documentationnot Cilium
  • Microservicesnot Cilium

Cilium

  • Kubernetes networking at a scale where iptables-based CNI performance degradesnot Asyncapi
  • Network policy expressed on workload identity rather than fragile IP rulesnot Asyncapi
  • Seeing which services actually talk to each other, and what policy is droppingnot Asyncapi

Where each one falls short

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

Asyncapi

  • Complex to implement and debug asynchronous operations due to their non-linear and concurrent nature
  • Keeping AsyncAPI documents up to date is challenging as systems evolve
  • Tracing and debugging asynchronous operations is more difficult than synchronous request-response patterns

Cilium

  • Requires a recent Linux kernel, which rules out older distributions and some managed environments
  • eBPF is genuinely hard to debug when it misbehaves, and the skill is rare on most teams
  • Broad scope — CNI, policy, mesh, observability — means the learning curve covers several domains at once

Pricing, plan by plan

Asyncapi

Free
  • Open SourceFree
    • AsyncAPI specification
    • Tools
    • Community support

Cilium

Free
  • CiliumFree
    • Full functionality
    • No usage limits
    • Community support

Which should you pick?

Choose Asyncapi if

  • You need api specification.
  • You want to start without paying.
  • You work on Web, CLI, IDE Extensions.
  • You also want code generation.
Asyncapi review

Choose Cilium if

  • You need ebpf datapath.
  • You want to start without paying.
  • You work on Kubernetes, Linux.
  • You also want identity-based policy.
Cilium review

Questions people ask

Is Asyncapi or Cilium better?
Neither clearly leads. Asyncapi starts at Free and Cilium at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Asyncapi or Cilium?
Asyncapi starts at Free and Cilium at Free.
Does Asyncapi or Cilium run on more platforms?
Asyncapi runs on Web, CLI, IDE Extensions. Cilium runs on Kubernetes, Linux.
Can I use Asyncapi for free?
Both have a free tier, so you can try either at no cost before committing.
What is Asyncapi best used for?
Asyncapi is most often used for api development, api gateway, api testing, api documentation. Of those, api development and api gateway are not what Cilium is typically brought in for.
What can Asyncapi do that Cilium cannot?
Asyncapi covers API Specification, Code generation, Documentation, Multiple messaging protocols. Cilium covers eBPF datapath, Identity-based policy, Hubble observability, Sidecar-free mesh.

Answered from the vendors’ own pages

Asyncapi: What is AsyncAPI used for?

AsyncAPI is an open-source specification for defining and documenting asynchronous APIs, message-driven systems, and event-driven architectures. It serves the same purpose for async APIs as OpenAPI does for REST APIs, providing standardized documentation, code generation, and tooling.

Source
Cilium: Is Cilium free?

Yes, open source and CNCF-graduated. Isovalent sells an enterprise distribution and support.

Asyncapi: Is AsyncAPI free to use?

Yes, AsyncAPI is completely free and open-source. It is hosted by the Linux Foundation and supported by community contributions and sponsorships from companies like Postman, IBM, IQVIA Technology, and Solace.

Source
Cilium: What does eBPF change?

It lets Cilium run packet-processing programs inside the kernel instead of relying on iptables rule chains, which behave poorly as the number of services grows.

Asyncapi: What protocols and technologies does AsyncAPI support?

AsyncAPI supports multiple protocols and technologies including Kafka, RabbitMQ, MQTT, Socket.IO, AWS EventBridge, and others. It provides language support for JavaScript/TypeScript, Python, Java, Go, C#/.NET, Kotlin, and PHP.

Source
Cilium: Does Cilium replace a service mesh?

It can cover much of what a mesh does without sidecars, though full mesh feature sets still favour Istio or Linkerd.

Asyncapi: Does AsyncAPI have IDE support?

Yes, AsyncAPI has IDE extensions available for VSCode and IntelliJ, along with CLI utilities and GitHub Actions integration for developers.

Source
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