Tonviewer vs TonScan: which explorer to choose

A block explorer is the window into a blockchain. Without one, any claim about a balance, a transfer history or an NFT status is hearsay. In the TON ecosystem two tools have historically competed for that role: Tonviewer and TonScan. Both are free, both cover the basics, but their philosophies and strengths diverge. By 2026 the question is not “which one is better” but “which one for which task”.

Tonviewer grew out of an internal Tonkeeper tool and now lives as part of the TonAPI stack. TonScan has been around since early TON mainnet and follows the classic explorer mould — long tables, data completeness, minimal visual polish — closer in spirit to Etherscan. Below we compare them by layer, from UX to API.

UX and first navigation

Tonviewer opens an address as an “account card”: balance on top, jetton list with icons below, NFT gallery underneath, and only then the transaction history grouped by type. The transaction tree (parent → child messages) is rendered as a graph, which helps a lot when dissecting DeFi operations where a single signature spawns six to ten internal messages.

TonScan shows the same data as classical tables. Jettons on a separate tab, NFTs on another, transactions as a single paginated list. For an experienced user this is faster: less visual noise, easier to copy raw values. For a beginner it is less friendly.

Data depth

This is where the difference is structural. TonScan traditionally exposes more “raw”: cell dumps, raw BOC, message op-codes, the exact compute_phase and action_phase values. If you are debugging a failed transaction where the contract returned a non-standard exit code, TonScan gives you the code and the cell structure to feed into a decoder.

Tonviewer covers 95% of user-level scenarios: “why my transfer did not arrive”, “which jetton was debited”, “who sent me this NFT”. But for inspector-mode development (what did this get-method return, what does the storage look like) TonScan and its neighbour verifier.ton.org are usually closer to hand.

API: developer view

TonAPI (Tonviewer): REST with key-based auth, SSE streams for address-level event subscriptions. Covers balance, jetton holdings, NFTs, events, DNS. Free tier is rps-capped, paid tiers are made for production loads. Docs are clean, community SDKs exist for TypeScript and Python.

TonScan API: narrower in endpoint coverage but adequate for basic queries — transactions per address, block info, jetton-master lookup by symbol. Suitable for admin scripts and infrequent calls; for a high-traffic app, TonAPI is the more practical choice.

Alternative to both: the official TON HTTP API (toncenter.com) and lite-client. Often used as a “no-third-party-indexer” source of truth.

Scenario 1: debug a failed transaction

You sent USDT through a swap aggregator and the wallet shows “Transaction failed”. Plan:

1. Tonviewer. Open the transaction by hash. The top will show the status and reason (e.g., compute_phase exit code 33). Drop into the tree to see which internal message returned the error and which contract emitted it.
2. TonScan, when you need detail. Open the same transaction by hash, switch to the Raw tab. You will see the exact cell dump, op codes, compute phase with gas_used and storage_fee.
3. Decoding the exit code. In TON the exit code depends on the contract. For jetton wallets, 705 is insufficient balance, 706 is wrong workchain. Compare against TEP-74 (jetton standard).
4. If still unclear — share the hash in a TON developer chat with screenshots from both explorers.

Scenario 2: tracing a phishing transfer

A classic TON attack is the “lookalike address”: a phisher generates a wallet whose first and last characters match the victim’s recipient. The victim’s history is then sprayed with zero-value transfers from the lookalike, so on next copy-paste from history they paste the attacker’s address.

How to read the explorer when suspicious:

• In Tonviewer open your address and filter by zero-value — you will see micro-inbound transfers from suspicious addresses.
• Compare the full attacker address to the legitimate one character by character. Explorers display shortened forms like UQAB…XYZ; always copy the full 48-character form to compare.
• For jetton “drop” phishing: check the jetton master — it must match the token’s public contract. TonScan exposes the master fastest via the Raw tab.

Scenario 3: inspecting an LP position

If you added liquidity on STON.fi or DeDust:

• Tonviewer surfaces the LP jetton in the regular jetton list and pulls a price hint from context.
• TonScan shows the LP jetton as a regular token; to see which assets back it you have to open the jetton master and call its get-methods.

For day-to-day monitoring Tonviewer is more convenient; for a pre-exit audit, TonScan plus a direct read of the protocol contract is safer.

Scenario 4: NFT collection inspection

Before buying an NFT on Getgems, the first thing to do is open the collection in an explorer and verify:

1. The collection address matches what is shown on the marketplace.
2. The publisher (collection owner) is a known party or an anonymous wallet with no history.
3. The item list: max supply, minted count, real sales activity.

Tonviewer is better for quick browsing — icons, previews, metadata. TonScan is better when you need to export the entire item list and confirm the royalty parameters match the advertised values.

Decision matrix

What neither explorer does

• They do not show off-chain context: fraud-signal ratings, exchange labels, KYT. For that you have Misttrack, Chainalysis Sandbox and tonviewer.com/threats (a Tonviewer tab with basic labels).
• They do not interpret complex DeFi operations semantically — “you swapped X for Y at this price”. That is the job of the wallet or dApp client, not the explorer.
• They do not insulate from human error. An explorer shows where the money went; it does not bring it back.

Bottom line

Tonviewer is the “user’s explorer”: visual, fast, with a readable transaction tree. TonScan is the “developer’s and auditor’s explorer”: raw data completeness, table-first format, verifiability emphasis. In 2026 both cover roughly 90% of daily tasks, and a sensible strategy is to keep both bookmarked and switch by context — Tonviewer for routine checks, TonScan for unusual scenarios.