From their user guide:

To ensure a smooth experience for everyone, please be aware of our transaction limits:

Volume

There is a sending cap of 2.500.000 sats and a receiving cap 1.000.000 sats over a rolling window of 7 days.

Balance

The maximum balance in your Alby account is currently limited to 1.000.000 sats.

Amounts

The maximum receivable amount per invoice is 250.000 sats . The maximum amount per outgoing payment is 500.000 sats.