EVM Decoding Functions

Functions to decode raw EVM events and function calls in DuneSQL.

EVM decoding functions let you decode raw event logs and function call traces inline in DuneSQL using a contract’s ABI. This is useful when you need to decode contracts that have not been submitted through Dune’s contract decoding pipeline, or when you want to decode data ad hoc without waiting for a submission to be processed.

Example Dashboard

Live examples of both functions applied to real contract data.

Before You Start

Finding a Contract’s ABI

These functions require the ABI for a single event or function, not the entire contract ABI.

To find the ABI for a specific event or function:

1. Go to the contract’s page on Etherscan (or the relevant chain’s block explorer).
2. Navigate to Contract > Code > Contract ABI.
3. Locate the JSON object for the specific event or function you want to decode.
4. Copy that single JSON object, not the full array.

Pass only the ABI for the specific event or function, not the entire contract ABI. Each decode_evm_event() or decode_evm_function_call() invocation expects a single ABI entry.

For more details on what an ABI is, see this guide.

Finding the topic0 for an Event

topic0 is the keccak256 hash of the event signature (name and parameter types). Use it to filter logs tables for specific events.

To find a topic0:

1. Open an example transaction on a block explorer.
2. Go to the Logs tab.
3. Identify the event and copy the value in the topic0 field.

Finding the MethodId for a Function Call

The MethodId is the first 4 bytes of the keccak256 hash of the function signature. Use it with starts_with(input, <MethodId>) to filter traces tables for specific function calls.

To find a MethodId:

1. Open an example transaction on a block explorer.
2. In the Overview tab, click Click to show more.
3. Copy the MethodId from the Input Data field.

Function Reference

decode_evm_event()

decode_evm_event(abi, input [, topics [, data [, null_on_error]]])

Decodes EVM events according to the provided ABI. Returns each decoded parameter as a separate column.

Arguments

Argument	Required	Type	Default	Description
abi	Yes	varchar		Event specification in JSON format. Must be constant at analysis time. Each input in the ABI produces one output column.
input	Yes	table		Table or subquery providing topics and data columns. Must be preceded with the TABLE keyword.
topics	No	descriptor	DESCRIPTOR(topic0, topic1, topic2, topic3)	Specifies which columns contain the event topics. Null topics are ignored.
data	No	descriptor	DESCRIPTOR(data)	Specifies which column contains the event data.
null_on_error	No	boolean	true	When true, decoding errors produce null values. When false, errors are raised.

Output

One column per parameter defined in the ABI inputs. Column names match the ABI parameter names, or default to _arg0, _arg1, etc. Columns are ordered with indexed inputs first.

All columns from the input table are passed through. The returned table contains one column for each ABI argument, followed by all columns from the input table.

Examples

• Basic Usage

SELECT * 
FROM TABLE (
    decode_evm_event (
      abi => '{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"buyer","type":"address"},{"indexed":true,"internalType":"address","name":"recipient","type":"address"},{"indexed":false,"internalType":"uint256[]","name":"tokensSoldIds","type":"uint256[]"},{"indexed":false,"internalType":"uint256[]","name":"tokensSoldAmounts","type":"uint256[]"},{"indexed":false,"internalType":"uint256[]","name":"currencyBoughtAmounts","type":"uint256[]"},{"indexed":false,"internalType":"address[]","name":"extraFeeRecipients","type":"address[]"},{"indexed":false,"internalType":"uint256[]","name":"extraFeeAmounts","type":"uint256[]"}],"name":"CurrencyPurchase","type":"event"}',
      input => TABLE (
        SELECT * 
        FROM polygon.logs
        WHERE topic0 = 0xb57378559821141c0e7ae964206b7523234d19e5783ade99b3d665eee495c997
        LIMIT 20
      )
    )
  )

• Using Custom Topics and Data Columns

SELECT * 
FROM TABLE (
    decode_evm_event (
      abi => '{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"buyer","type":"address"},{"indexed":true,"internalType":"address","name":"recipient","type":"address"},{"indexed":false,"internalType":"uint256[]","name":"tokensSoldIds","type":"uint256[]"},{"indexed":false,"internalType":"uint256[]","name":"tokensSoldAmounts","type":"uint256[]"},{"indexed":false,"internalType":"uint256[]","name":"currencyBoughtAmounts","type":"uint256[]"},{"indexed":false,"internalType":"address[]","name":"extraFeeRecipients","type":"address[]"},{"indexed":false,"internalType":"uint256[]","name":"extraFeeAmounts","type":"uint256[]"}],"name":"CurrencyPurchase","type":"event"}',
      input => TABLE (
        SELECT topic0 as my_topic_0, topic1 as my_topic_1, topic2 as my_last_topic, data as my_data_column, * 
        FROM polygon.logs
        WHERE topic0 = 0xb57378559821141c0e7ae964206b7523234d19e5783ade99b3d665eee495c997
        LIMIT 20
      ),
      topics => DESCRIPTOR(my_topic_0, my_topic_1, my_last_topic),
      data => DESCRIPTOR(my_data_column),
      null_on_error => false
    )
  )

decode_evm_function_call()

decode_evm_function_call(abi, data [, input [, output [, null_on_error]]])

Decodes EVM function calls according to the provided ABI. Returns each decoded input and output parameter as separate columns.

Arguments

Argument	Required	Type	Default	Description
abi	Yes	varchar		Function call specification in JSON format. Must be constant at analysis time. Each input and output in the ABI produces one output column.
data	Yes	table		Table or subquery providing input and output columns. Must be preceded with the TABLE keyword.
input	No	descriptor	DESCRIPTOR(input)	Specifies which column contains the function call input bytes.
output	No	descriptor	DESCRIPTOR(output)	Specifies which column contains the function call output bytes.
null_on_error	No	boolean	true	When true, decoding errors produce null values. When false, errors are raised.

Output

One column per input and output defined in the ABI. Column names match the ABI parameter names, or default to _input0, _input1, _output0, _output1, etc. If two arguments share the same name, the last declared argument takes precedence.

All columns from the data table are passed through. The returned table contains one column for each ABI argument, followed by all columns from the data table.

Examples

• Basic Usage

SELECT * 
FROM TABLE (
    decode_evm_function_call (
      abi => '{"name":"getPlanet","type":"function","inputs":[{"name":"planetId","type":"uint256"}],"outputs":[{"name":"planetName","type":"string"},{"name":"planetType","type":"string"}]}',
      data => TABLE (
        SELECT * 
        FROM polygon.traces
        WHERE starts_with(input, 0x34efcb8e)
        LIMIT 20
      )
    )
  )