Jupiter Adds Solana Transaction V1 Support to jup.ag Swaps and Jupiter Wallet

Jupiter JUP$0.329-2.2%, the Solana swap aggregator behind the JUP token, switched on support for Solana's Transaction V1 format in the jup.ag swap interface and the Jupiter Wallet browser extension on 28 September 2026. The change gives Jupiter's router more room to pack multi-pool routes into a single transaction, and the official Jupiter Trade account claims "better execution on 18% of pairs" as a result, without saying how it measured that figure.

What Solana Transaction V1 changes for Jupiter swap routing

Transaction V1 went live on Solana mainnet at epoch 1035 on 15 September 2026, raising the maximum transaction size from 1,232 bytes to 4,096 bytes, as we covered when the format activated. Jupiter shipped support thirteen days later.

For an aggregator, transaction size is a routing constraint. A swap that splits across several liquidity pools has to carry every pool's instructions and accounts in one transaction to settle atomically, meaning all legs fill or none do. Routes that overflowed the old 1,232-byte ceiling could not be sent that way. The Solana Foundation's own analysis of the V1 trade-offs lists traders and routers among the main beneficiaries, noting that "larger transactions can support more complex atomic routes."

Address lookup tables and the 64-account limit in Tx V1

The extra room comes with a cost. V1 drops address lookup tables (ALTs), the v0 feature that let a transaction reference an account by a short index into a stored list instead of writing out its full 32-byte address. In V1, every account is written inline, up to a cap of 64.

The Solana Foundation's analysis puts the price of that at roughly 31 net bytes for every address a v0 transaction previously loaded through an ALT, and finds that around 62% of observed v0 transactions reference at least one ALT. For half of current transactions, the conversion to V1 adds less than 420 bytes, well inside the roughly 2,860 bytes of new headroom. The same analysis notes that the unchanged 64-account limit "can still constrain account-heavy applications," so the widest routes remain bounded by account count even where bytes are no longer the problem.

Jupiter Wallet and wallet support for Tx V1

A V1 swap only reaches a trader whose wallet can sign it. Under the upgrade spec, wallets signal support through a supportedTransactionVersions setting, and "a wallet must only advertise a version it can actually sign." Jupiter is using that gap to promote its own extension.

The Jupiter Manage account's post opens with "Solana just made room for more inside every transaction. But you only feel it if your wallet supports it," then says the Jupiter Wallet "supports Tx v1 from day one," promising "bigger routes, better fills, lower cost." Ledger hardware wallet users are still waiting: a request for V1 support in Ledger's Solana app, opened on 2 September 2026, was still open on 28 September. Jupiter's posts did not say how jup.ag handles wallets that have not added V1.

Jupiter's 30-day swap volume and the 18% of pairs claim

Jupiter's aggregator program processed about $23.0 billion in spot swap volume across roughly 109 million swaps between 29 August and 27 September 2026, according to Solana Compass program analytics. At that scale, a routing change touching nearly a fifth of pairs is material.

Share of pairs and share of volume are different measures, though. The 18% could sit mostly in a long tail of thinly traded tokens that need multi-hop routes, or in heavier pairs that already route through several pools. Jupiter has not published which, nor the share of swap volume or the average price improvement on the routes that now fit.

Tx V1 routing is live now on jup.ag and in the Jupiter Wallet extension.