Transaction details: Design cancel flow

[GBKS]

Bitcoin transactions cannot be cancelled directly, but outstanding transactions can be overridden with new transactions that spend the funds back to yourself (therefore making the original transaction invalid).

Some ways this can be done (via Claude):

1. Replace-by-Fee (RBF):

   • If the original transaction was sent with RBF enabled, you can replace it with a new transaction that sends the coins back to yourself.
   • This new transaction must have a higher fee to be accepted by miners.

2. Double spend:

   • Attempt to send the same coins to a different address (or back to yourself) with a higher fee.
   • This is essentially what RBF does, but in a more standardized way.

3. Wait for the transaction to be dropped:

   • If a transaction remains unconfirmed for a long time (usually 14 days), most nodes will eventually drop it from their mempool.
   • The funds will then be available to spend again.

4. Use a "double-spend-as-a-service" tool:

   • Some services claim to help cancel transactions by broadcasting conflicting transactions.
   • Use these with caution as they're not always reliable or safe.

Important considerations:

• Once a transaction is confirmed (included in a block), it cannot be cancelled.
• These methods only work for unconfirmed transactions.
• Success isn't guaranteed, especially if the original transaction has a competitive fee.

Replace-by-fee is also part of the fee bumping user flow to be designed in #115. Similar to that issue, this feature is likely an addition to the transaction details page, covered in the activity page of the design docs.