A Cosmos Hub transfer without the memo an exchange asked for still succeeds: the ATOM reaches the shared deposit address, but the exchange cannot tell which customer sent it.
Why the memo matters
Every Cosmos SDK transaction has an optional free-text memo field, described in the Cosmos SDK transactions docs. The network does not interpret it, but exchanges use it to match deposits to accounts. It cannot be added after the transaction is in a block.
What to do
- Do not resend or send a separate "memo" payment.
- Find the transaction on Mintscan (see our Mintscan guide) and note hash, addresses, amount, time and the expected memo.
- Contact the recipient's official support; for a swap, include the order number.
- Be ready to prove you control the sending address, and ignore paid "recovery agents".
Manual processing can take longer than a normal deposit, and some services charge for it, so ask about their conditions first.
For IBC transfers from other Cosmos chains, the memo field may be used by the protocol itself. If an exchange needs a memo, first move the ATOM to your own cosmos1 address and send a regular transfer from there.
Changing the memo afterwards is impossible, so keep the hash handy.
Swapping ATOM
On the ATOM to USDT page, copy the memo if the order shows one; if not, leave the field empty. Pay within an hour, and never reuse an expired order's address. Withdrawals to your own Keplr wallet normally need no memo.
FAQ
Can I add a memo after sending ATOM?
No. Only the recipient can match the payment using the transaction data.
Do I need a memo for my own Keplr address?
Usually not; memos are for shared exchange addresses.