The fees channel sends every exchange fee event from the Polymarket exchange contracts (v1 and v2). We decode each one and send it after the transaction is confirmed on-chain. Fees are no longer part of the trading channel; they stream here so you can track fee flow on its own.
Subscribe
{
"action": "subscribe",
"id": "s1",
"channel": "fees"
}
Filters
| Filter | Type | Required | Description |
|---|
wallets | string[] | No | Hex addresses (0x…). Keeps fees whose receiver is a listed address. |
token_ids | string[] | No | Token IDs as decimal strings. Keeps fees on the listed outcome tokens. |
market_ids and min_usd — they have no effect here. See Filters for the combination rule.
Events
This channel sends both exchange fee events.
| Event | data.type | Description |
|---|
FeeChargedV1 | fee_charged_v1 | A fee charged on exchange v1. Carries the receiver, token id, and fee amount. |
FeeChargedV2 | fee_charged_v2 | A fee charged on exchange v2. Simplified to the receiver and fee amount. |
Payloads
Every frame wraps the event in the standard envelope (type, id, channel, confirmed, data) shown on Frames. Below, each block is the data object for one event — its type discriminator plus every field the ABI decodes. A full frame looks like:
{
"type": "event",
"id": "s1",
"channel": "fees",
"confirmed": true,
"data": {
"type": "fee_charged_v1",
"receiver": "0x…",
"tokenId": "0x…",
"amount": "0x…"
}
}
fee_charged_v1
FeeCharged on CTFExchange v1 / NegRiskCTFExchange v1. Carries the receiver, the token the fee was taken on, and the fee amount.
{
"type": "fee_charged_v1",
"receiver": "0x…",
"tokenId": "0x…",
"amount": "0x…"
}
| Field | Solidity type | Description |
|---|
type | string | fee_charged_v1. |
receiver | address (hex) | Address that received the fee. |
tokenId | uint256 (hex) | Outcome token the fee was taken on. |
amount | uint256 (hex) | Fee amount. |
fee_charged_v2
FeeCharged on CTFExchange v2 / NegRiskCTFExchange v2. The v2 signature dropped tokenId, so it carries only the receiver and the amount.
{
"type": "fee_charged_v2",
"receiver": "0x…",
"amount": "0x…"
}
| Field | Solidity type | Description |
|---|
type | string | fee_charged_v2. |
receiver | address (hex) | Address that received the fee. |
amount | uint256 (hex) | Fee amount. |
Pending feed
Set confirmed: false on your subscribe to get the pending feed of this channel — the same payload shape for pending exchange transactions, before they are in a block. Pending events are guesses. A transaction can be dropped, replaced, or reverted. See Mempool for the full frame shape and how to handle it.
{
"action": "subscribe",
"id": "pending",
"channel": "fees",
"confirmed": false
}
Last modified on July 5, 2026