Okay, so check this out—Solana moves fast. Really fast. Transactions blur past in slots and signatures, and if you’re trying to debug a failed transfer or build analytics you can feel a little lost. Whoa! The good news: block explorers and on-chain analytics give you a magnifying glass. The trick is knowing where to look, what to trust, and what’s just noise.

At a glance, a Solana transaction is a signed message that executes one or more instructions against one or more programs during a specific slot. Medium-level detail is usually enough to solve common problems: fee breakdowns, pre/post balances, instruction logs, and inner instructions. Longer forensic work asks harder questions—rent, CPI (cross-program invocation) side effects, or subtle state changes that only show up after a sequence of writes and account reallocations.

Screenshot of a Solana transaction view showing instructions and logs

Using an Explorer like solscan to speed debugging

Tools like solscan give an immediate, human-readable window into a signature: who signed, which programs ran, and where lamports moved. Seriously? Yes. Open a signature and you’ll typically see: slot number, block time, status (Success or Failed), fee, pre- and post-balances, and logs emitted by programs. Those logs are gold when a CPI or a program panic is the culprit.

Short tip: start with the status and logs. If a transaction failed, logs usually show the program error string (or a program ID and an error code). Then scan pre/post balances to confirm whether the change was a transfer, rent collection, or account creation. Also watch for new accounts being created—those trigger rent-exempt transfers and can look like unexpected SOL outflows.

Deeper dives mean correlating instructions. A token transfer via the SPL Token program affects an associated token account, not the owner’s main SOL balance. So seeing “SOL decreased” and thinking the token transfer charged you SOL is a common beginner mistake. The fee and rent charges are the SOL moves—token balances live in separate accounts.

One more heads-up: slot vs blocktime. Slots are the ordering units; timestamps are derived and can be off a bit depending on the validator that produced the block. If you’re doing time-series analytics, rely on blocks/slots for ordering and use block time as an approximate timestamp.

Key fields to check in transaction JSON

When you fetch a transaction using RPC (getTransaction) or inspect it in an explorer, these fields matter most:

  • signature — unique ID for the transaction
  • slot — ordering unit
  • meta.status — success or error (with error code)
  • meta.fee — lamports paid for the transaction
  • meta.preBalances / meta.postBalances — SOL changes per account
  • meta.innerInstructions — instructions invoked by programs (very useful)
  • transaction.message.instructions — top-level instructions
  • logMessages — program logs emitted during execution

Those innerInstructions entries are often overlooked, though they explain nested token moves made by another program on your behalf. If you’re tracking DeFi flows, inner instructions tell the real story. On the other hand, logs can be noisy—some programs log everything. So filter and search for error strings or key events.

(oh, and by the way…) If a transaction created an account, that’s frequently why balances don’t sum the way you expect. Account creation transfers lamports for rent-exemption and shows up as a SOL decrease even if no “transfer” instruction to a user happened.

Analytics: what to measure and how to collect it

For product metrics or dashboards you’ll want structured events rather than raw transaction blobs. Capture these pieces: transaction time (slot), program IDs involved, instruction types (transfer, mint, swap), token mints, involved accounts, fee paid, and success/failure. Then enrich with known mappings—DEX program IDs, token metadata, and token decimals—so amounts become human-readable.

Streaming subscriptions via RPC (logsSubscribe, accountSubscribe) get you near-real-time data. But be realistic: RPC rate limits and historical gaps mean you often need a hybrid approach—stream for live, then backfill by indexing the ledger or using a third-party indexer. Many analytics teams rely on a dedicated indexer that ingests confirmed blocks and emits normalized events; building one takes work, but it’s the only way to guarantee complete historical coverage without relying on external APIs.

Signal vs noise: filter by program ID and by instruction type before storing everything. Otherwise storage and query costs balloon. Also compute units and innerInstructions counts can be metrics themselves—spikes often correlate with complex DeFi operations or malicious transaction attempts.

Practical debugging checklist

Follow this quick sequence when a transaction misbehaves:

  1. Check transaction status and logs first.
  2. Verify pre/post balances and fees to isolate SOL moves.
  3. Inspect innerInstructions for CPI activity.
  4. Look at program error codes and map them to program docs.
  5. Simulate the transaction locally (simulateTransaction) to reproduce errors without submitting.
  6. If it’s a wallet UX issue, confirm the wallet signed the exact message (message.instructions).

My instinct says simulate early. Simulate before spending real SOL. It saves headaches. Actually, wait—replaying a failing transaction under different recent blockhashes sometimes changes the outcome, so simulation is necessary but not always sufficient.

FAQ

How can I see which tokens moved in a transaction?

Look at innerInstructions and the parsed instruction data. Explorers parse common programs (SPL Token, Serum, Raydium) into readable token transfers, but raw transaction JSON still contains the instruction bytes. Parsed logs and the token transfer events in explorers are the fastest route.

Why did my SOL balance change even though I only sent an SPL token?

Because token accounts are separate on Solana. Creating an associated token account requires SOL for rent-exempt balance, and fees are paid in SOL. Check meta.preBalances/postBalances to find the rent or fee movements.

Is RPC data reliable for analytics?

RPC is reliable for recent, confirmed data, but historical completeness depends on provider retention and limits. For robust analytics, combine RPC streaming with an indexer or a trusted third-party dataset to backfill and handle reorgs and slot-finalization nuances.