How Sending Works
Two things about sending BTCZ tend to surprise people: a tiny payment can take longer to send than a huge one, and over time your balance quietly splits itself into many small pieces. Both come down to a single idea about how a private wallet actually stores your money.
The one idea
Your balance is not a single number. It is a stack of separate coins, called notes. Sending speed depends on how many notes you spend, not on how much they are worth, because every note must be sealed with its own zero-knowledge proof. That single fact explains why "send everything" is slow, why millions can move in seconds, and why Z-Text keeps your funds split into many small notes.
Your balance is a stack of notes
When you open your wallet you see one balance. Underneath, that balance is made of many individual coins. In a shielded wallet like Z-Text these coins are called notes (the technical name is an unspent transaction output, or UTXO). Each note has a fixed value, and your balance is simply the sum of all your notes.
The key rule: you spend whole notes, never part of one. This works just like cash. If you hold a single coin worth 10 and you want to pay 2, you cannot tear the coin in half. You hand over the whole coin and receive change.
Spending and change
Because you spend whole notes, almost every send produces change. Suppose you spend a note worth 0.01 BTCZ to send 0.0002. The network takes a tiny fee (0.0001 BTCZ), your recipient receives their amount, and the rest comes back to you as a brand-new note. The note you spent is gone; in its place you now hold a fresh change note.
This is why your note values keep shifting as you use the wallet. It is also why a freshly created change note needs a moment to confirm before you can spend it again, which matters more than you might expect (see below).
Why speed depends on note count, not amount
Here is the part that catches people out. To spend a note privately, your phone has to build a zero-knowledge proof for it: a small cryptographic proof that you own the note and are allowed to spend it, without revealing which note it is. Building one proof takes roughly one to three seconds on a phone.
Crucially, there is one proof per note you spend. A transaction that spends 1 note needs 1 proof. A transaction that spends 50 notes needs 50 proofs. The size of the amounts does not matter at all; only the number of notes does.
Rule of thumb
Sending speed depends on how many notes you spend, not on how much BTCZ you send.
| What you send | Notes spent | Proofs | Speed |
|---|---|---|---|
| 5,000,000 BTCZ in one note | 1 | 1 | Seconds |
| 1 BTCZ across 100 notes | Many | Many | Tens of seconds to minutes |
| Send Max (everything) | Every note you own | All of them | Slowest, sent in batches |
Worked examples
Sending one message
A message spends a single small note. Z-Text keeps notes of about 0.0002 BTCZ for exactly this: enough to cover the 0.0001 sent to your contact plus the 0.0001 network fee. One note, one proof, done in a couple of seconds. And in a two-way conversation the 0.0001 you send comes back to you when your contact replies, so the real cost of chatting is close to just the fee.
5,000,000 BTCZ in one note vs 1 BTCZ in a hundred notes
If your five million BTCZ happen to sit in a single note, sending them is one proof, over in a few seconds. If instead you hold 1 BTCZ spread across a hundred tiny notes, spending most of it means proving dozens of notes, which takes far longer, even though the amount is millions of times smaller. Count, not amount.
Sending everything
"Send Max" is the slowest thing you can ask the wallet to do, because it has to spend every note you own. There are so many proofs that they do not even fit in one transaction, so the wallet sends your balance in several back-to-back transactions (up to about 50 notes each), pausing to grind out the proofs for each batch, roughly a minute or two per batch on a phone. A wallet with 200 notes becomes about four sequential transactions. It is the clearest proof that cost tracks the number of notes, not the amount.
Why Z-Text splits your funds
If many notes make sending slow, why does Z-Text deliberately split your funds into lots of small ones? Because messaging is the opposite problem. Every message you send spends one note. If your whole balance sat in a single note, you could only send one message at a time: after each send you would have to wait for the change to confirm before you could send the next.
With a pool of many small notes, each message simply grabs a different ready note, so you can fire off many messages back to back without waiting. One note means one message at a time; a hundred notes means a hundred messages in flight.
The waiting trap
If you try to send a second message while the first one's change has not yet confirmed, the send fails, because your only spendable note was just used. A healthy pool of already-confirmed notes is what makes rapid messaging feel instant. A confirmation takes about one block, roughly two and a half minutes.
So Z-Text splits a large note into many small notes of about 0.0002 BTCZ in a single transaction (one note becomes a hundred, for one small fee), and a new license arrives with a ready-made pool of notes so you can start chatting right away.
Keeping your note pool healthy
You do not have to manage any of this by hand. The wallet watches your note count and shows you its health: a comfortable pool is around fifty or more notes, and it flags when you are running low. Receiving messages tops you up too, because every message you receive hands you a note back, so an active conversation naturally replenishes your pool.
If you ever want to top up manually, for example before sending a burst of messages, you can split your balance into fresh notes in one tap from Settings → Note Management. It is a single transaction with a single fee.
Glossary
| Term | Meaning |
|---|---|
| Note | A single shielded coin of a fixed value. Your balance is the sum of your notes. |
| UTXO | "Unspent transaction output" — the technical name for a note. |
| Change | The leftover value from a spent note, returned to you as a new note. |
| Dust | A very small amount, such as the 0.0001 BTCZ attached to a message. |
| Network fee | The small amount (0.0001 BTCZ) the blockchain charges to process a transaction. |
| zk-SNARK proof | The zero-knowledge proof built for each note you spend. It makes sends private, and it is what takes the time. |
| Confirmation | A note becomes reliably spendable once its transaction is included in a block, about every 2.5 minutes. |
Common questions
Why does Send Max take so long?
It spends every note you own, and each note needs its own proof. With many notes the wallet has to send your balance in several sequential batches, building the proofs for each. It is working, not stuck.
Why is a small payment sometimes slower than a large one?
Because speed depends on how many notes the payment uses, not the amount. A small payment that has to gather many tiny notes can be slower than a large one that uses a single big note.
Why did my balance split into lots of tiny amounts?
That is intentional. A pool of small notes lets you send many messages quickly without waiting for change to confirm.
Did I lose coins when my balance split?
No. Splitting costs only one small network fee. And the dust attached to messages comes back to you in two-way conversations.
My send has been working for a while. Is something broken?
Usually not. A send that spends many notes simply needs time to build all the proofs. It is almost always proof generation, not a network or balance problem.