Decentralized Exchanges on TRON: SunSwap, JustSwap, and Why Swap Activity Isn't Origin

Walk through enough TRON walletsSoftware or hardware that stores private keys and uses them to sign transactions. A wallet holds keys, not coins — balances live on the ledger itself — so the same funds can be reached from any wallet loaded with the same keys, and losing the wallet loses nothing if the keys are backed up elsewhere. and a second pattern emerges, distinct from the USDT-dominated transfer activity. A handful of contract addresses keep showing up — sometimes as the destination, sometimes routing internal flows that touch four or five other contracts in a single transactionA signed instruction ("tx" for short) that changes on-chain state — transferring value, calling a contract, or updating an account's settings. Once it is included in a block and that block reaches finality the record is permanent: later transactions can supersede its effects, but the entry itself can never be edited or deleted. Before finality, a freshly included transaction can still be reversed if its block is reorganized out.. Those are TRON’s decentralized exchangesAn exchange implemented as smart contracts: traders swap tokens directly from their own wallets against on-chain liquidity, so no operator ever takes custody of funds. On TRON the principal DEX is SunSwap — formerly JustSwap, rebranded in 2021 when Sun.io absorbed it, so older on-chain activity against JustSwap contracts belongs to the same protocol., and they’re one of the easiest signals to misread.

A wallet that hits a router contract within minutes of activation looks, at a glance, like the router created it. It didn’t. TRON’s protocol rules forbid that reading: the wallet was created by an externally-owned accountAn account controlled by a private key held by a person or organization, as opposed to a contract account controlled by code. The term comes from Ethereum, but the distinction applies on TRON too: every externally initiated transaction begins with an EOA's signature, so tracing who acts on a chain ultimately means tracing EOAs., then immediately started trading. Knowing which contracts are which, and why none of them can be a wallet’s origin, is the line between accurate attributionThe process of identifying the entity most likely to control a blockchain address by combining on-chain signals — who created and funded it, how it transacts, which keys can act for it — with known service patterns and labels. Attribution conclusions are evidence-weighted judgments, not certainties, and are strongest when several independent signals converge. and a wrong conclusion drawn from noise.

One protocol, three brand eras

TRON’s DEX activity is dominated by SunSwap, and most of the confusion an investigator hits traces to its history: three brand names and several router replacements over six years.

JustSwap launched on August 18, 2020, built by the TRON Foundation and modeled on Uniswap. Justin Sun’s launch open letter compared it directly to Uniswap and reported $5.8 million in trading volume within fifteen hours of going live. It was a stand-alone product under the Foundation’s justswap.io brand.

SunSwap absorbed JustSwap on October 20, 2021, framed by the Foundation as a SUN.io acquisition. On-chain, nothing moved. The original JustSwap Factory at TXk8rQSAvPvBBNtqSoY6nCfsXWCSSpTVQF is today officially tagged on TronScan as SUN: SunSwapV1 Factory, and its bytecode hasn’t changed since 2020. Only the label did. So a wallet whose pre-October-2021 history shows “JustSwap” interactions is pointing at the same addressA public identifier, derived from a key pair, at which an account receives funds and is looked up on-chain. Anyone can view an address's history, but only the matching private key can spend from it. TRON addresses are 34-character Base58Check strings beginning with "T". now called SunSwap V1. There’s no separate JustSwap protocol to research and no migration event in the data — both names describe one set of contracts.

SunSwap V2 went live on December 21, 2021, redeployed as a Uniswap V2 fork. The router’s on-chain name is literally UniswapV2Router02: the team forked the upstream codebase and redeployed it on TRON. It charges the same 0.3% per-trade fee, but splits it 0.25%/0.05% between LPs and SUN-token holders rather than sending the whole fee to LPs the way upstream Uniswap V2 does.

SunSwap V3 followed on June 28, 2023, forking Uniswap V3 — concentrated liquidity and four fee tiers (0.01%, 0.05%, 0.3%, 1%). As of July 2026, V3 is the active liquidity venue on TRON; V2’s own liquidity drained away after V3’s launch, though its router remained in use for pass-through volume from aggregator routing. That split can shift, so for current TVL and volume by version, DefiLlama’s per-protocol SunSwap pages are the live reference to reverify against.

The Smart Router moving target

Above the three versioned pool sets sits a router that can split one user swap across V1, V2, V3, and SUN.io’s stableswap venues in a single transaction. The team has reissued it three times, and the rotation is the part that trips people up.

The first Smart Exchange Router (TCFNp179Lg46D16zKoumd4Poa2WFFdtqYj) is tagged deprecated on TronScan. So is the second-generation one (TJ4NNy8xZEqsowCBhLvZ45LCqPdGjkET5j). The current top of stack is the Universal Router (TSJEtPuqHpvSaVnSwvCsngaeBxrGUzp95Q), launched February 5, 2026 alongside a Permit2 deployment — and already tagged deprecated by TronScan within three months. That deprecation tag is the rotation signal to watch.

The takeaway: the V2 and V3 routers and factories are stable; the Smart/Universal Router is not. A wallet’s “smart router” interactions from 2022 resolve to a different address than its 2026 ones. Memorize the V2 and V3 anchors and look up the current top-of-stack router on TronScan when you need it.

Contract address reference

These come from upstream attestation — the sun-protocol GitHub deployment tables and TronScan’s public contract-tag registry — not a third-party catalog. The V2 and V3 anchors are the ones to memorize; the Smart/Universal Router rotates.

Component	Address	Notes
SunSwap V2 SwapRouter	TNJVzGqKBWkJxJB5XYSqGAwUTV15U24pPq	Verbatim Uniswap V2 fork; tag SUN: SunSwap V2Router
SunSwap V2 Factory	TKWJdrQkqHisa1X8HUdHEfREvTzw4pMAaY	Spawns V2 pair contracts
SunSwap V3 SwapRouter	TQAvWQpT9H916GckwWDJNhYZvQMkuRL7PN	Verbatim Uniswap V3 fork; tag SUN: SunSwapV3 SwapRouter
SunSwap V3 Factory	TThJt8zaJzJMhCEScH7zWKnp5buVZqys9x	Spawns V3 pool contracts
SunSwap V3 NonfungiblePositionManager	TLSWrv7eC1AZCXkRjpqMZUmvgd99cj7pPF	V3 LP positions tokenized as NFTs
SunSwap V3 Quoter	TLhZ48yfHygMLM2uZr87zJJusHjGen97gh	Off-chain price-quoting helper
SunSwap V1 Factory (ex-JustSwap)	TXk8rQSAvPvBBNtqSoY6nCfsXWCSSpTVQF	Bytecode unchanged since 2020; rebranded Oct 2021
Smart Exchange Router (deprecated)	TCFNp179Lg46D16zKoumd4Poa2WFFdtqYj	First-generation multi-pool router
Smart Exchange Router (deprecated)	TJ4NNy8xZEqsowCBhLvZ45LCqPdGjkET5j	Second-generation multi-pool router
Universal Router (Feb 2026; tagged deprecated by May 2026)	TSJEtPuqHpvSaVnSwvCsngaeBxrGUzp95Q	Current routing surface; rotation imminent
Permit2	TTJxU3P8rHycAyFY4kVtGNfmnMH4ezcuM9	ERC-2612-style approval delegation companion to Universal Router

Beyond SunSwap proper, the routable surface as of May 2026 includes SUN.io’s stablecoinA token designed to hold a steady value against a reference asset, most commonly one US dollar. The target is maintained either by an issuer holding reserves that back and redeem the token, or algorithmically through mint-and-burn incentives — two very different risk models behind the same face value. venues — a peg-stability module (PSM) and a Curve-style stableswap pool (“SunCurve”) — plus a few adjacent contracts. The SunPump token-launch router uses bonding-curve mechanics rather than constant-product AMM and shows up in wallets trafficking newly-launched TRC-20TRON's smart-contract standard for fungible tokens, derived from Ethereum's ERC-20: a compliant contract exposes transfer, approve, allowance, and transferFrom, and emits Transfer and Approval events. USDT on TRON is issued as a TRC-20 token. Because every TRC-20 transfer is a contract call, it consumes Energy (plus Bandwidth) and — unlike a TRX or TRC-10 transfer — cannot activate a not-yet-created account. tokensA unit of value recorded inside a smart contract rather than in the chain's native ledger — the contract keeps the balance table, and moving tokens means asking the contract to update it. Not to be confused with a coin, which is the chain's built-in asset (TRX on TRON) used to pay for the network itself.. It doesn’t have SunSwap’s depth or scale and needs no more than a mental footnote: it’s a swap-related router that never qualifies as an origin candidateAn address or entity identified as a plausible creator or funder of a target address, ranked by the strength of the on-chain evidence tying it to the target's creation and early funding history. Treating origin as a set of ranked hypotheses, rather than a single asserted answer, keeps the conclusion proportionate to the evidence..

What a swap looks like on-chain

A single SunSwap V2 swap appears in a wallet’s history as a TriggerSmartContract call to the V2 router (TNJVzGqK…), invoking one of the standard Uniswap V2 methods — swapExactTokensForTokens, swapTokensForExactTokens, swapExactTRXForTokens, and the rest. The router then calls into one or more pool contracts, each holding two token reserves whose product stays constant as trades shift the balance.

Each pool touched emits the standard Uniswap V2 Swap event:

Swap(address indexed sender, uint amount0In, uint amount1In,
     uint amount0Out, uint amount1Out, address indexed to)

with topic-0 hashA fixed-length fingerprint computed from data of any size by a one-way function: the same input always produces the same output, but the output reveals nothing about the input and no practical method finds a second input that matches it. Transaction IDs and block IDs are hashes, and each block embeds the previous block's hash — which is what makes tampering with history detectable. 0xd78ad95fa46c994b6551d0da85fc275fe613ce37657fb8d5e3d130840159d822. Two fields matter for attribution:

• sender is whoever called into the pool — almost always the router contract, not the user.
• to is whoever receives the output tokens. For a direct user swap that’s the user; for a multi-hop route it can be an intermediate pool.

So an address showing up as to tells you the wallet received output tokens from a DEX trade. It does not tell you the wallet’s owner initiated it. Aggregators and arbitrage bots route output to other parties’ addresses routinely.

Smart Router swaps inflate the noise further. A single Universal or Smart Router call encodes a multi-pool path as one calldata payload: the user submits one outbound transaction, and the receipt logs Swap events from every pool the route touched — potentially mixing V1, V2, V3, and stableswap pools in one trade. An investigator scanning the wallet’s “interactions list” sees what looks like activity across many contracts. It was one swap.

That’s the on-chain reason frequent DEX-router interaction can masquerade as heavy DeFiDecentralized finance — financial services (trading, lending, borrowing, earning yield) delivered by smart contracts that hold funds and enforce terms directly on-chain, with no bank or broker as intermediary. Anyone with a wallet can interact with a DeFi protocol, and every position and movement is publicly recorded. behavior when it isn’t. A handful of routine swaps inflates a wallet’s contract-interaction count enough to stand out, with no unusual behavior behind it — any analyst counting distinct contracts a wallet has touched should calibrate for this router noise.

Why a DEX router can never be a wallet’s origin

The reason is older than TRONORIGIN and every SunSwap brand era: a TRON smart contractA program deployed to a blockchain that runs deterministically when called, holding its own state and balance and enforcing its rules without any operator's ongoing involvement. Because a contract executes code rather than acting on anyone's initiative, its address represents logic — funds can flow through it, but the contract itself is not a person or a controlling entity. is never credited as a wallet’s origin. Even when a contract’s internal transfer triggers activation, the record names the external account that signed the call — see Account Activation for the full mechanics — and routers are smart contracts. A router cannot, at the protocol level, be the credited actor that brought a wallet into existence.

That makes DEX-router-as-origin a deterministic false positive. If any analysis ever surfaced a router as the most-likely origin, it would be wrong before any evidence was weighed.

The practical consequence for any analyst: DEX-router and factory addresses — across SunSwap, JustSwap, JustLend, SUN.io, SunPump, and ParaSwap — should be set aside as origin candidates, because none of them can create an account. One caveat is worth keeping: if a wallet’s history contains only DEX router interactions and no other plausible candidate, that router activity is all the record offers, so it’s what you fall back to. The common case — a heavy DeFi user with both router noise and real funding flows — is easier: drop the routers and the real funding flows come into view.

The investigator-facing version: when a wallet’s earliest transactions are all SunSwap router calls, the read isn’t “created by SunSwap.” It’s “activated by an EOA a careful trace should be able to identify, then immediately started swapping.” Reach for the activation event — the very first transaction — and the funding source behind it.

Investigative takeaways

Three things to reuse on every TRON-DEX-touching wallet.

The V2 and V3 anchors are what you memorize — TNJVzGqK… (V2 Router) and TQAvWQpT… (V3 SwapRouter). They’ve been stable for years and likely stay that way. The Smart Router rotates; don’t memorize it, look it up.

JustSwap and SunSwap are the same protocol. Any pre-October-2021 “JustSwap” reference points at addresses now officially labeled SunSwap V1. The rebrand was a label change with no migration, and the contract at TXk8rQSA… is the canonical proof.

And swap activity is not origin — the most common noise pattern on TRON histories and the most-misread one. Set it aside because the protocol forbids contracts from being origins, a hard rule rather than an editorial preference. When your own analysis flags a router as a candidate, that’s a bug. Trace back to the activation event and the EOA behind it.

Sources

• TRON DAO Medium — Justin’s Open Letter on JustSwap Launch (Aug 18, 2020) — primary, TRON Foundation, signed by Justin Sun; establishes JustSwap’s launch date, the direct Uniswap comparison (“We’ve accomplished in a dozen hours what Uniswap took a dozen months to achieve”), and the launch-volume figure: “Within 15 hours, the trading volume on JustSwap has surpassed 5.8 million USD.”
• TRON DAO Medium — SUN.io Officially Acquires JustSwap (Oct 20, 2021) — primary, TRON Foundation announcement of the rebrand.
• SunSwap Zendesk — Announcement on SUN’s Acquisition of JustSwap — primary, SunSwap support docs; corroborates the acquisition and rename.
• sun-protocol/sunswap-v2-contracts (GitHub) — primary, protocol team’s own repo; canonical V2 deployment addresses and UniswapV2Router02 contract name.
• sun-protocol/SunswapV3Contracts (GitHub) — primary; V3 deployment addresses.
• sun-protocol/smart-exchange-router (GitHub) — primary; documents multi-version routing across V1/V2/V3/PSM/SunCurve.
• SUN.io Zendesk — Announcement on Launching SunSwap V3 (June 28, 2023) — primary; V3 launch date and concentrated-liquidity design.
• SUN.io Zendesk — Universal Router & Permit2 Upgrade (Feb 5, 2026) — primary; Universal Router and Permit2 contract addresses and launch date.
• DefiLlama — SunSwap V3 protocol page — primary data provider; live TVL and 24h volume by protocol version.
• DefiLlama — SunSwap V2 protocol page — primary; documents the V2 TVL collapse and continued routing-volume pass-through.
• DefiLlama — SunSwap V1 protocol page — primary; V1 TVL.
• Uniswap V3 Pool events reference — primary; Swap event signaturesA cryptographic proof, produced with a private key over a transaction's exact contents, that the key holder authorized that transaction and no other. Nodes verify the signature before accepting the transaction, so a valid signature is definitive evidence the key was used — though not of who was holding it at the time. that SunSwap V3 inherits unchanged.
• TronScan public contract-tag API — primary; on-chain contract identity attestation for every address listed in the reference table.
• TRONORIGIN attribution methodology (proprietary) — the project’s own analysis approach; applies the DEX-router exclusion described here and the protocol rule that a contract is never credited as an account’s origin.