Reads an account's runtime bytecode from live RPC state, the exact state identified by a pinned CLIENT, or retained execution state. Without a CLIENT, it builds a reusable READ and does not access state.
Local
SELECT code_at('0x0000000000000000000000000000000000000001'::ADDRESS);Exact signatures with descriptions, requirements, inputs, returns, and examples.
code_at(CLIENT, ADDRESS) # Immediate Read · RPC required Reads the CLIENT's current state context. For live clients that means latest; pinned and execution clients retain their own exact state identity.
| Name | Type |
|---|---|
code | BYTES |
Deployed bytecode. Returns runtime bytecode as BYTES. A live RPC no-code response is NULL; pinned and execution state represent known no-code as empty BYTES. NULL or empty client, NULL address, and live RPC/decoding failures return NULL. Historical live reads and pinned-state hydration may require archive access.
The two-argument overload reads latest from a live CLIENT, so its result can change between runs.
Use block_number for reproducible bytecode evidence. Older heights may require an archive-capable provider.
Relation-sized attached pinned reads may share one hash-pinned JSON-RPC batch; each request retains the CLIENT's block hash and canonicality requirement.
An explicit block number is valid only for a live CLIENT. Supplying one for pinned or execution state raises STATE_SOURCE_INCONSISTENT.
Pinned reads use the CLIENT's block hash and canonicality requirement. An inconsistent identity or provider result raises STATE_SOURCE_INCONSISTENT.
A detached pinned CLIENT can use retained state only; a cache miss raises HYDRATION_UNAVAILABLE. Attached pinned hydration can also raise HYDRATION_UNAVAILABLE when its provider cannot be reached.
Pinned hydration reports HISTORICAL_STATE_UNAVAILABLE when the provider does not retain the required state.
Execution reads use retained execution state and raise CHECKPOINT_UNAVAILABLE when that state cannot be resolved.
The READ accesses state only when an OBSERVATION consumes it during PROGRAM execution.
code_at(CLIENT, ADDRESS, BIGINT) # Immediate Read · RPC required Reads runtime bytecode at an exact block height through a live CLIENT. Pinned and execution CLIENTs reject an explicit height because their state identity is already fixed.
| Name | Type | Use |
|---|---|---|
client | CLIENT Readable EVM state represented by a live, pinned, or retained execution CLIENT. | required positional |
address | ADDRESS Account address whose runtime bytecode should be read. | required positional |
block_number | BIGINT Optional historical height for a live CLIENT. NULL is equivalent to omitting the argument. | required positional |
| Name | Type |
|---|---|
code | BYTES |
Deployed bytecode. Returns runtime bytecode as BYTES. A live RPC no-code response is NULL; pinned and execution state represent known no-code as empty BYTES. NULL or empty client, NULL address, and live RPC/decoding failures return NULL. Historical live reads and pinned-state hydration may require archive access.
Named parameters · RPC required
SELECT code_at(
$client, -- client
'0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2'::address, -- Ethereum mainnet WETH
21000000 -- Ethereum mainnet block number
) AS code;code_at(ADDRESS) # Read Builder · RPC required Records one address for a later account-code lookup; construction does not access state.
Named parameters · RPC required
SELECT code_at(
$client, -- client
'0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2'::address -- Ethereum mainnet WETH
) AS code;