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APIs · head to head

Asyncapi vs Griffin

Asyncapi logo

Asyncapi

APIs

Specification and tools for defining asynchronous APIs

From
Free
Rated
-
Full reviewWebsite
Griffin logo

Griffin

APIs

UK banking-as-a-service from a company that holds its own full banking licence

From
£100/month
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; Griffin platform banking carries a one-off onboarding fee from 15,000 pounds and a 3,500 pound monthly minimum, which prices out early-stage companies entirely.
  • They diverge on capability: Asyncapi covers API Specification, Griffin covers Bank accounts by API.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Asyncapi and Griffin actually diverge.

Attributes where Asyncapi and Griffin differ
AttributeAsyncapiGriffin
Starting priceFree£100/month
Pricing modelopen-sourcePer month with usage drawdown
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 Griffin

  • Bank accounts by API
  • UK payment rails
  • Integrated ledger
  • Automated onboarding
  • Debit cards
  • Interest on balances

What people use each for

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

Asyncapi

  • API Developmentnot Griffin
  • API Gatewaynot Griffin
  • API Testingnot Griffin
  • API Documentationnot Griffin
  • Microservicesnot Griffin

Griffin

  • A wealth platform that must hold client money in a licensed bank rather than an EMI safeguarding accountnot Asyncapi
  • A lender wanting UK accounts and payment rails without becoming a bank itselfnot Asyncapi
  • A fintech burned by sponsor bank instability that wants the deposit holder and the API provider to be the same entitynot Asyncapi
  • A platform needing sub-account ledgering for pooled client funds with a clean audit trailnot 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

Griffin

  • Platform banking carries a one-off onboarding fee from 15,000 pounds and a 3,500 pound monthly minimum, which prices out early-stage companies entirely.
  • It is UK-only, so a business with European or US operations needs a second banking provider and a second integration for those entities.
  • It is a young bank with a small balance sheet relative to incumbents, and enterprise counterparties still ask hard questions about concentration risk.
  • Holding a banking licence means Griffin applies bank-grade due diligence to its own clients, so onboarding is slower and more selective than an EMI-based provider.
  • Feature breadth is narrower than long-established providers, particularly in card programme management and in payment types beyond core UK rails.

Pricing, plan by plan

Asyncapi

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

Griffin

£100/month
  • Business Banking$100/month
    • From 100 pounds per month
    • Interest or commission from around 1.75 percent AER variable
    • Operational accounts and UK payment rails
  • Platform Banking$3500/month
    • One-off onboarding fee from 15,000 pounds
    • Minimum monthly spend of 3,500 pounds, drawn down by usage
    • Higher committed tiers at 5,000 and 10,000 pounds with discounts
  • Enterprise$undefined/month
    • Custom pricing
    • Bespoke account structures and volumes
    • Negotiated interest or commission share

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 Griffin if

  • You need bank accounts by api.
  • You work on Web, REST API.
  • You also want uk payment rails.
Griffin review

Questions people ask

Is Asyncapi or Griffin better?
Neither clearly leads. Asyncapi starts at Free and Griffin at £100/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Asyncapi or Griffin?
Asyncapi has a free tier; the other does not. Paid plans start at Free for Asyncapi and £100/month for Griffin.
Does Asyncapi or Griffin run on more platforms?
Asyncapi runs on Web, CLI, IDE Extensions. Griffin runs on Web, REST API.
Can I use Asyncapi for free?
Yes. Asyncapi has a free tier, so you can try it without paying. Griffin starts at £100/month.
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 Griffin is typically brought in for.
What can Asyncapi do that Griffin cannot?
Asyncapi covers API Specification, Code generation, Documentation, Multiple messaging protocols. Griffin covers Bank accounts by API, UK payment rails, Integrated ledger, Automated onboarding.

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
Griffin: Is Griffin actually a bank?

Yes. It received a UK banking licence with restrictions in March 2023 and a full licence in March 2024 after exiting mobilisation.

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
Griffin: What does it cost?

Business banking from 100 pounds a month; platform banking from a 15,000 pound onboarding fee plus a 3,500 pound monthly minimum drawn down by usage.

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
Griffin: Does it cover Europe?

No. Griffin is a UK bank serving UK accounts and UK payment rails.

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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