The PSB API is fully described as an OpenAPI 3.0 specification. If you work in a language without an official SDK (Python, Java, TypeScript, Go, Ruby, and so on), generate a typed client from swagger.json.

The current specification is available via:

• Swagger UI: psb.econnect.eu — download swagger.json via the button at the top
• Direct URL: https://psb.econnect.eu/swagger/v1/swagger.json

In some environments a subscription key is required as a query parameter:

https://psb.econnect.eu/v1/swagger.json?subscriptionKey={your-subscription-key}

The PSB documentation on psb.econnect.eu describes this pattern in the SDK examples.

Install OpenAPI Generator CLI and choose a generator (-g) for your language:

openapi-generator-cli generate \
  -i https://psb.econnect.eu/swagger/v1/swagger.json \
  -g java \
  -o ./psb-client-java

Other common generators:

OpenAPI Generator supports more than 50 languages. See the generator list for options per language.

The PHP SDK repository shows codegen with a custom package name:

openapi-generator-cli generate \
  -g php \
  -i "https://psb.econnect.eu/v1/swagger.json?subscriptionKey={your-subscription}" \
  -o ./psb-client-php \
  --additional-properties=invokerPackage=EConnect\\Psb

For .NET projects, NSwag is an alternative alongside the official EConnect.Psb package:

nswag openapi2csclient /input:https://psb.econnect.eu/swagger/v1/swagger.json /output:PsbClient.cs

EConnect.Psb additionally provides DI registration, token management and webhook validation that a pure codegen client does not have.

Generated clients do not include OAuth2 token management by default. You implement yourself:

1. Obtain a token via POST /connect/token on the Identity Server
2. Send the Bearer token in the Authorization header
3. Refresh the token before expiry (tokens are valid for about one hour)

See Authentication for the Client Credentials and Resource Owner flows.

Example with curl (basis for your own token logic):

TOKEN=$(curl -s -X POST https://accp-identity.econnect.eu/connect/token \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "grant_type=client_credentials" \
  -d "client_id=your-client-id" \
  -d "client_secret=your-client-secret" \
  -d "scope=ap" | jq -r '.access_token')

In production, cache the token and refresh it only shortly before expiry — not on every API request.

During development the Swagger UI is useful to:

• Explore endpoints by functional area (SalesInvoice, Hook, Peppol, and so on)
• Inspect request and response schemas
• Run test calls with your Bearer token