• Obtain a token:

curl --location 'http://localhost:8080/authenticate' \
--header 'Content-Type: application/json' \
--data '{
    "username": "admin",
    "password": "admin"
}'

• Use the token in subsequent requests as a Bearer token:

curl --location 'http://localhost:8080/customers' \
--header 'Authorization: Bearer <TOKEN>'

• Create loan using /loan endpoint like following:

curl --location 'http://localhost:8080/loan' \
--header 'Authorization: Bearer <TOKEN>' \
--header 'Content-Type: application/json' \
--data '{
    "customerId": 1,
    "loanAmount": 120.89,
    "interestRate": 0.1,
    "numberOfInstallment": "SIX"
}'

• Pay a loan using /payment endpoint like following:

curl --location 'http://localhost:8080/payment' \
--header 'Authorization: Bearer <TOKEN>' \
--header 'Content-Type: application/json' \
--data '{
    "loanId": 1,
    "amount": 50
}'