> For the complete documentation index, see [llms.txt](https://docs.symm.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.symm.io/trader-documentation/building-a-trading-bot/part-1-one-time-on-chain-setup/delegate-the-session-key.md).

# Delegate the session key

Session keys are how you avoid wallet popups on every trade. Generate an ephemeral keypair, give it on-chain authority to sign for your sub-account for some bounded time window, and then let it sign all the EIP-712 trade messages off-chain. The [InstantLayer](/trader-documentation/how-trading-works-in-symmio/instant-trading.md#the-instant-layer) verifies these delegations on every `executeBatch` / `executeTemplate` call: when your session key's signature recovers, the InstantLayer checks that the calldata's selector is in the active delegated set for `(sub, sessionKey)`.

**Signed by.** Owner EOA. The call goes to the InstantLayer.

**Function.** `grantDelegation(DelegationInfo info)`, where `DelegationInfo` is:

```
struct DelegationInfo {
    Account  account;            // (subAccount, isPartyB=false)
    address  delegatedSigner;    // the session key's address
    bytes4[] selectors;          // what they're allowed to sign for
    uint256  expiryTimestamp;    // unix seconds
}
```

The selectors are where this gets subtle. You need five of them:

| Selector     | Meaning                                                         |
| ------------ | --------------------------------------------------------------- |
| `0xa6d66852` | `addMarginToNextVA`: pre-funding a VA before opening a position |
| `0xa7f3b34b` | `sendQuoteWithAffiliateAndData`: opening a position             |
| `0x501e891f` | `requestToClosePosition`: closing a position                    |
| `0xeaa31b19` | ID the COH (TP/SL service) keys delegations under               |
| `0x00000001` | ID services use to verify session-key auth                      |

The first three are real Symmio function selectors, and the InstantLayer checks them on every `executeBatch`. The last two are four-byte tags the off-chain services use as lookup keys when they answer "is this session key authorized to talk to me?" 

{% hint style="info" %}
**Note.** The `grantDelegation` tx is sent from your owner EOA, but once it lands, the *session key* (not the EOA) is what signs all subsequent EIP-712 messages on the trade path.
{% endhint %}


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