Free Basic capstone · offline worksheet
Verify the transfer claim
Use the evidence shown here to practice a bounded conclusion about one SOL transfer and one SPL token transfer. Both cases are fictional. The identifiers are labels, not valid addresses or real signatures. You do not need a wallet, an RPC request, a transaction, or SOL to complete this exercise.
Safety: Never enter a recovery phrase, private key, or secret into a worksheet or course site. A signature and an account change can support a statement about network activity; they do not, by themselves, prove a person's identity, intent, or ownership of an exchange balance.
Case A · native SOL
Did 0.2 SOL reach the destination?
A reviewer queried the fictional Mainnet example at finalized commitment. The transaction was found, its execution error was null, and the only value-moving instruction was a System Program transfer. For this exercise, use the reported fee below; do not assume that every real transaction has the same fee.
SOL_SIGNATURE_EXAMPLEmeta.err = null| Account role | Before | After | Change |
|---|---|---|---|
| Sender and fee payer | 1,000,000,000 | 799,995,000 | Calculate |
| Destination | 50,000,000 | 250,000,000 | Calculate |
- Calculate both balance changes. Remember that one SOL is 1,000,000,000 lamports.
- Separate the sender's transfer amount from the fee deducted from the fee payer.
- Does the destination increase match the inferred transfer? State what the provided instruction and metadata do, and do not, establish.
Check the arithmetic after you try
The sender's total decrease is 200,005,000 lamports. Subtract the 5,000-lamport fee to infer a 200,000,000-lamport transfer, or 0.2 SOL. The destination increases by 200,000,000 lamports, so its change matches the inferred transfer in this supplied two-account scenario. That does not establish who controlled either key or why the transfer was made.
Case B · SPL token
Did 2.5 tokens move between token accounts?
This fictional transaction contains one successful classic SPL Token transfer. The mint has six decimals. Its fee payer also paid the network fee in SOL; that fee is not part of the token amount.
TOKEN_SIGNATURE_EXAMPLEEXAMPLE_MINT_NOT_AN_ADDRESSmeta.err = null| Token account role | Before (raw) | After (raw) | Change (raw) |
|---|---|---|---|
| Source token account | 10,000,000 | 7,500,000 | Calculate |
| Destination token account | 1,250,000 | 3,750,000 | Calculate |
- Calculate each raw-unit change and convert it using the mint's six decimals.
- Use
preTokenBalancesandpostTokenBalances. Confirm the entries refer to the same mint and the source and destination account indices. - Distinguish the runtime account owner (the Token Program) from the token authority (the wallet allowed to authorize movement).
- State why this token-account evidence and the SOL fee are separate facts.
Check the arithmetic after you try
The source decreases by 2,500,000 raw units and the destination increases by the same amount. With six decimals, 2,500,000 ÷ 1,000,000 = 2.5 tokens. The separate 5,000-lamport network fee is paid in SOL and is not subtracted from either token balance.
Evidence report
Write only what the evidence supports
For a real read-only investigation, record the cluster, RPC or explorer, query time, requested commitment, signature, slot, execution result, fee payer and fee, relevant instruction, and the account evidence you used. If the RPC returns null or omits a field, record it as unavailable and check the cluster and provider; do not infer failure or success from missing data.
Read the primary sources