Swarm Desktop must be configured as a light node in order to access stamp related features. If you have not already upgraded from the default ultra-light configuration, complete the upgrade by following the instructions here.
Postage stamps are required in order to upload data to Swarm. Postage stamps are purchased by interacting with the Swarm postage stamp smart contract on Gnosis Chain. Postage stamps are not purchased one by one, rather they are purchased in batches only.
How to Buy a Postage Stamp Batch
Stamps can be purchased by selecting Stamps from the Account tab:
And then clicking the Buy New Postage Stamp button:
Depth and Amount
Batch depth and amount are the two required parameters which must be set when purchasing a postage stamp batch. Depth determines how many chunks can be stamped with a batch while amount determines how much xBZZ is assigned per chunk.
Inputting a value for depth allows you to preview the upper limit of data which can be uploaded for that depth.
Note that a batch will become fully utilized before the upper limit has been reached, so the actual amount of data which can be uploaded is lower than the limit. At higher depth values, this becomes less of a problem as batch utilization will come closer to the upper limit on average as the depth increases. For this reason, Swarm Desktop requires a minimum batch depth of 24.
Inputting a value for amount and depth together will allow you to also preview the total cost of the postage stamp batch as well as the TTL (time to live - how long the batch can store data on Swarm). Click the Buy New Stamp button to purchase the stamp batch.
After purchasing stamps you can view stamp details from the Postage Stamps drop down menu: