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APIs · head to head

Asyncapi vs i2c

Asyncapi logo

Asyncapi

APIs

Specification and tools for defining asynchronous APIs

From
Free
Rated
-
Full reviewWebsite
i2c logo

i2c

APIs

Configurable card issuing and banking processing platform for banks and programme managers

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; i2c developer experience lags API-native competitors, and teams expecting Stripe-grade documentation and sandboxes find an enterprise integration project instead.
  • They diverge on capability: Asyncapi covers API Specification, i2c covers Configurable product engine.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Asyncapi and i2c actually diverge.

Attributes where Asyncapi and i2c differ
AttributeAsyncapii2c
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 i2c

  • Configurable product engine
  • Credit and instalments
  • Multi-currency
  • Fraud and risk tooling
  • Digital banking front ends
  • Global scheme connectivity

What people use each for

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

Asyncapi

  • API Developmentnot i2c
  • API Gatewaynot i2c
  • API Testingnot i2c
  • API Documentationnot i2c
  • Microservicesnot i2c

i2c

  • A bank wanting credit, debit and prepaid portfolios on one processor rather than threenot Asyncapi
  • An issuer in a market where local scheme and currency support rules out US-centric processorsnot Asyncapi
  • A programme manager launching instalment products without building a lending corenot Asyncapi
  • A credit union replacing an ageing processor without writing custom code for product rulesnot 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

i2c

  • Developer experience lags API-native competitors, and teams expecting Stripe-grade documentation and sandboxes find an enterprise integration project instead.
  • Implementations lean on i2c or partner professional services, so timelines and costs are set by a services queue rather than by your own engineering speed.
  • Pricing is per active card and per transaction with monthly minimums, none of it published, so comparing bids requires modelling your own portfolio carefully.
  • Configuration flexibility means product behaviour lives in platform settings rather than in your repository, which complicates version control, testing and audit trails.
  • As a private company with a broad global footprint, regional support depth is uneven, and a programme in a smaller market may get thinner service than a flagship account.

Pricing, plan by plan

Asyncapi

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

i2c

On request
  • i2c processing platform$undefined/year
    • Per-active-card and per-transaction processing fees
    • Minimum monthly commitments by programme
    • Implementation and configuration professional services

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 i2c if

  • You need configurable product engine.
  • You work on Web, REST API.
  • You also want credit and instalments.
i2c review

Questions people ask

Is Asyncapi or i2c better?
Neither clearly leads. Asyncapi starts at Free and i2c at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Asyncapi or i2c?
Asyncapi has a free tier; the other does not. Paid plans start at Free for Asyncapi and On request for i2c.
Does Asyncapi or i2c run on more platforms?
Asyncapi runs on Web, CLI, IDE Extensions. i2c runs on Web, REST API.
Can I use Asyncapi for free?
Yes. Asyncapi has a free tier, so you can try it without paying. i2c 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 i2c is typically brought in for.
What can Asyncapi do that i2c cannot?
Asyncapi covers API Specification, Code generation, Documentation, Multiple messaging protocols. i2c covers Configurable product engine, Credit and instalments, Multi-currency, Fraud and risk tooling.

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
i2c: Does i2c issue the cards itself?

No. It processes; issuance sits with a bank or licensed issuer, and in most markets you need that relationship separately.

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
i2c: Can it handle revolving credit?

Yes. Credit, instalments and buy-now-pay-later sit on the same platform as debit and prepaid, which is unusual among modern processors.

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
i2c: Is it self-serve?

No. Expect a configuration-led implementation with professional services rather than signing up and calling an API.

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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