# `BankingCircle.Schemas.Payment`
[🔗](https://github.com/iamkanishka/banking_circle/blob/main/lib/banking_circle/schemas/payment.ex#L1)

Validates and casts a single-payment request before it's sent to
`POST /payments/singles`, using an Ecto embedded schema purely as a
typed-casting + changeset-validation tool (no database involved).

Catching malformed requests client-side — wrong currency format, missing
beneficiary details, negative amounts — avoids a round trip for errors
that are knowable before the request ever leaves the BEAM.

# `build`

```elixir
@spec build(map()) :: {:ok, map()} | {:error, Ecto.Changeset.t()}
```

Validates and returns `{:ok, payload_map}` ready for JSON encoding, or
`{:error, %Ecto.Changeset{}}` with field-level errors.

# `changeset`

```elixir
@spec changeset(map()) :: Ecto.Changeset.t()
```

Builds a changeset from a map of attributes (string or atom keys).

## Examples

    iex> BankingCircle.Schemas.Payment.changeset(%{
    ...>   debtor_account_id: "acc_123",
    ...>   amount: Decimal.new("100.50"),
    ...>   currency: "EUR",
    ...>   creditor_name: "Jane Doe",
    ...>   creditor_iban: "DE89370400440532013000",
    ...>   transaction_reference: "INV-2026-001"
    ...> }).valid?
    true

---

*Consult [api-reference.md](api-reference.md) for complete listing*