0x Swap API on Solana supports Transaction v1

0x Swap API on Solana includes Transaction v1 support, letting you take advantage of Solana's larger transaction format. Bigger transactions allows trades to route through more liquidity venues in a single swap.

On Solana, transaction size can be a limiting factor in finding the best possible route. Raising transaction size limits facilitates more competitive pricing, with more routes compared and more liquidity available. This helps deliver an improved trade experience, especially for high value swaps, where using multiple assets and liquidity pools help deliver more value per trade.

How transaction size affects pricing

Transaction v1 raises the memory limit that a Solana transaction can hold, from 1,232 bytes to 4,096 bytes, almost 4 times the cap set in v0. That gives 0x room to compare pricing over more complex, fragmented routes.

Optimal trade execution usually means hopping between different assets and protocols, calculating a route that would deliver more value to the traders’ wallet. Each hop means another instruction needs to be coded into the transaction, so increasing the limit makes room to create even more competitive routes.

Switch to Transaction v1

Enabling v1 is as simple as adding transaction_version to the request body. Everything else about the call is unchanged.

{
  "transaction_version": "v1",
  "reserve_transaction_accounts": 2
}

reserve_transaction_accounts is the minimum number of static account keys kept free for your own instructions (v1 only). See the full request and response fields in the API reference.

The response takes the same shape as v0, so you can just compile the instructions into a v1 transaction, sign and submit.

Choosing between v0 and v1

• v0 is still supported. The Transaction version can be set per request, as needed. Use v1 wherever your signing path supports it, and fall back to v0 elsewhere.
• Wallet support decides the version for wallet-signed flows. If a wallet can't sign v1, request v0 for that user. Apps that sign and submit directly (intent-based or server-side) can use v1 no matter which wallet your users hold.

Benefits of v1

Long-tail swaps: For newer or lesser-known venues which may not have previously had an address lookup table, transaction v1 enables these to be considered alongside more established venues.

Fragmented liquidity: A trading app may quote a size too large for one venue. Transaction v1 gives the router more room to split it across multiple venues in one swap.

Construct faster: v1 lists every account inline instead of using address lookup tables, so this can make transaction construction faster and less complex to reason about.

Transaction v1 shipped with Agave 4.2.2 and is available to all API customers via 0x Swap API on Solana, currently in open beta. Sign up for a free 0x account to try Transaction v1 in your product today. Get your API key.