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APIs · head to head

Asyncapi vs Zimpler

Asyncapi logo

Asyncapi

APIs

Specification and tools for defining asynchronous APIs

From
Free
Rated
-
Full reviewWebsite
Zimpler logo

Zimpler

APIs

Nordic and Brazilian account-to-account payments for regulated high-risk sectors

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Asyncapi has a free tier, so it costs nothing to try first.
  • Each has a real cost: Asyncapi complex to implement and debug asynchronous operations due to their non-linear and concurrent nature; Zimpler pricing is not published and is set by industry and risk profile, so smaller merchants cannot benchmark a quote and often discover they are paying well above a general-purpose provider.
  • They diverge on capability: Asyncapi covers API Specification, Zimpler covers Bank payments.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Asyncapi and Zimpler actually diverge.

Attributes where Asyncapi and Zimpler differ
AttributeAsyncapiZimpler
Starting priceFreeOn request
Pricing modelopen-sourcequote
Free tierYesNo
PlatformsWeb, CLI, IDE ExtensionsWeb, REST API
Founded2019Unknown

Identical on both: user rating (Not yet rated), category (APIs).

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 Zimpler

  • Bank payments
  • BankID identity
  • Payouts
  • Recurring payments
  • Risk screening
  • Brazil coverage

What people use each for

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

Asyncapi

  • API Developmentnot Zimpler
  • API Gatewaynot Zimpler
  • API Testingnot Zimpler
  • API Documentationnot Zimpler
  • Microservicesnot Zimpler

Zimpler

  • A Swedish gambling operator needing deposit and verified identity in a single customer flownot Asyncapi
  • A Nordic merchant wanting instant bank payouts rather than card refundsnot Asyncapi
  • A trading platform where confirming account ownership before funding is a regulatory requirementnot Asyncapi
  • A European operator expanding into Brazil and wanting one provider across both marketsnot 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

Zimpler

  • Pricing is not published and is set by industry and risk profile, so smaller merchants cannot benchmark a quote and often discover they are paying well above a general-purpose provider.
  • As a payment facilitator carrying merchant risk, it declines or offboards merchants on risk grounds, which makes it a dependency you cannot assume will persist.
  • Its strength is concentrated in the Nordics, and coverage in southern and eastern Europe is thinner than pan-European account-to-account specialists.
  • Revenue concentration in iGaming ties the provider to a sector under constant regulatory change, so licence changes in one market affect the supplier as well as the merchant.
  • Bank transfers have no chargeback protection, so disputes are handled commercially and consumers used to card protections may resist the payment method.

Pricing, plan by plan

Asyncapi

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

Zimpler

On request
  • Zimpler payments$undefined/year
    • Per-transaction pricing quoted by industry, risk and volume
    • Separate pricing for payouts and identity verification
    • Merchant underwriting required, with sector restrictions

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 Zimpler if

  • You need bank payments.
  • You work on Web, REST API.
  • You also want bankid identity.
Zimpler review

Questions people ask

Is Asyncapi or Zimpler better?
Neither clearly leads. Asyncapi starts at Free and Zimpler at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Asyncapi or Zimpler?
Asyncapi has a free tier; the other does not. Paid plans start at Free for Asyncapi and On request for Zimpler.
Does Asyncapi or Zimpler run on more platforms?
Asyncapi runs on Web, CLI, IDE Extensions. Zimpler runs on Web, REST API.
Can I use Asyncapi for free?
Yes. Asyncapi has a free tier, so you can try it without paying. Zimpler starts at On request.
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 Zimpler is typically brought in for.
What can Asyncapi do that Zimpler cannot?
Asyncapi covers API Specification, Code generation, Documentation, Multiple messaging protocols. Zimpler covers Bank payments, BankID identity, Payouts, Recurring payments.

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
Zimpler: Which markets does Zimpler cover?

Sweden and the Nordics primarily, plus the wider EU and Brazil. It is strongest where national electronic identity schemes exist.

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
Zimpler: Does it handle identity verification?

Yes. In the Nordics it captures BankID identity alongside the payment, which removes a separate verification step.

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
Zimpler: Is pricing published?

No. It is quoted per merchant based on sector, risk and volume, and merchants must pass underwriting first.

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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