The `pydantic_extra_types.routing_number` module provides the [`ABARoutingNumber`](/guides/pydantic-extra-types-pydantic-extra-types-routing-numbers#abaroutingnumber) data type.

## ABARoutingNumber

**Bases:** [`str`](https://docs.python.org/3/builtins/stdtypes.html#str)

The `ABARoutingNumber` data type is a string of 9 digits representing an ABA routing transit number.

The algorithm used to validate the routing number is described in the [ABA routing transit number](https://en.wikipedia.org/wiki/ABA_routing_transit_number#Check_digit) Wikipedia article.

```py
from pydantic import BaseModel

from pydantic_extra_types.routing_number import ABARoutingNumber

class BankAccount(BaseModel):
    routing_number: ABARoutingNumber

account = BankAccount(routing_number='122105155')
print(account)
# > routing_number='122105155'
```

## Related pages

- [API Documentation](./api-documentation-index.md)
- [Concepts](./concepts-index.md)
- [Dev Tools](./dev-tools-index.md)
- [Error Messages](./error-messages-index.md)
- [Examples](./examples-index.md)
- [Integrations](./integrations-index.md)
- [Internals](./internals-index.md)
- [Production Tools](./production-tools-index.md)
- [Pydantic](./pydantic-index.md)
- [Pydantic Core](./pydantic-core-index.md)

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