Transactions/tx_version

Which transaction version is this?

$0.01per call after 25 free a day

Says whether a transaction is legacy, version 0 or version 1, and which readers (RPC settings and library versions) can read it.

Run when code can't find or read a transaction that is on chain, or before relying on code that reads other people's transactions.

Saves money. About 45% of Solana transactions are version 1 since September 15, 2026, and apps that read with version 0 silently miss them: payments rejected, trades not copied, burns not credited.

Call it

Transport	How
HTTP	`POST /api/tools/tx_version` with a JSON body of the inputs below.
MCP	`tools/call` with name `tx_version` on `/mcp`.

Inputs

Name	What it's looking for	Where to get it
`tx_id` string (base58), optional	A landed transaction's signature. Give this or tx.	Returned when it was sent, or from history. Never make one up.
`tx` string (base64), optional	A raw transaction, signed or not. Give this or tx_id.	The bytes a wallet or builder gave you, base64-encoded.
`network` "mainnet-beta" \| "devnet", optional	Default "mainnet-beta" (real money).	"devnet" only for test wallets.

Returned fields

Every field the tool returns, what it is, and exactly how it's worked out.

Field	What it is	How it's worked out
`version` "legacy" \| "0" \| "1" \| "unknown"	The transaction's format.	tx_id: the version the RPC reports, asked with maxSupportedTransactionVersion 1. tx: read from the first bytes (see notes).
`readable_with_max_version_0` boolean \| null	Whether code asking with maxSupportedTransactionVersion: 0 can read it. null when the version is unknown.	True for legacy and 0, false for 1.
`who_can_read_it` string	Which RPC settings and library versions can read this format.	Fixed text per version, from mainnet tests of each library version (2026-10-30).
`fix` string \| null	What to change so code reads it. null when nothing needs changing.	Given for version 1.
`found / slot / time` boolean / number \| null / string \| null	For tx_id: whether the transaction was found, and where and when it landed.	From getTransaction (finalized or confirmed).
`source` string	Where the version came from.	"rpc getTransaction" or "transaction bytes".

Limits

Version 1 transactions start with the byte 0x81, before the signatures; legacy and version 0 start with the signature count. Code that parses raw bytes the old way breaks on version 1 too.
Version 1 went live on mainnet on 2026-09-15; the first one we found is in slot 447120004.