The European Banking API on OpenAPI v3

The Berlin Group, an European Standard initiative, recently released its OpenAPI v3 specifications for NextGenPSD2 XS2A Framework, and it’s French counterpart, STET, did the same with their 1.4 spec

The Berlin Group v1.3 specs leverages:

  • problem+json rfc7807 for describing error messages, extending the previous custom json error response;
  • the draft-cavage for signatures, still without addressing the representation metadata issues related to that signature model.

Both specs converges to a definition of currency amount, based on two different strings. String datatype is used to avoid floating point approximations in javascript operations. Eg.

js> 0.1 + 0.2 // results in
0.30000000000000004

and delegate where possible to the backend implementation.