# Get a proof for a transaction in a block.

GET

/v2/blocks/{round}/transactions/{txid}/proof

## Authorizations

- **[api\_key](https://dev.algorand.co/reference/rest-api/algod/#api_key)**

## Parameters

### Path Parameters

**round**  
required  
integer  
A round number.

**txid**  
required  
string  
/[A-Z0-9]+/  
The transaction ID for which to generate a proof.

### Query Parameters

**hashtype**  
string  
Allowed values:  sha512\_256  sha256  
The type of hash function used to create the proof, must be one of:
- sha512\_256
- sha256

**format**  
string  
Allowed values:  json  msgpack  
Configures whether the response object is JSON or MessagePack encoded. If not provided, defaults to JSON.

## Responses

### 200

Proof of transaction in a block.

Select media type application/json

Proof of transaction in a block.

object

**hashtype**  
required  
The type of hash function used to create the proof, must be one of:
- sha512\_256
- sha256  
string  
Allowed values:  sha512\_256  sha256

**idx**  
required  
Index of the transaction in the block’s payset.

integer

**proof**  
required  
Proof of transaction membership.

string format: byte  
/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$/

**stibhash**  
required  
Hash of SignedTxnInBlock for verifying proof.

string format: byte  
/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$/

**treedepth**  
required  
Represents the depth of the tree that is being proven, i.e. the number of edges from a leaf to the root.

integer

### 400

Malformed round number or transaction ID

Select media type application/json

An error response with optional data field.

object

**data**  
object

**message**  
required  
string

### 401

Invalid API token

Select media type application/json

An error response with optional data field.

object

**data**  
object

**message**  
required  
string

### 404

Non-existent block or transaction

Select media type application/json

An error response with optional data field.

object

**data**  
object

**message**  
required  
string

### 500

Internal error, including protocol not supporting proofs.

Select media type application/json

An error response with optional data field.

object

**data**  
object

**message**  
required  
string

### default

Unknown error