Orders

Get a combined platform + exchange fee quote for a prospective trade

Prices a trade you are considering WITHOUT submitting it: for a market order (order_type=market, price omitted) the live orderbook is walked for quantity to compute a size-weighted executable price; for a limit order (order_type=limit) price is required and used as the resting quote. Shares the exact computation used by the WebSocket RFQ stream (subscribe_fee_quote), so the two surfaces can never price a trade differently. Quotes are display-only, degrade-open estimates (is_estimate: true) — the authoritative fee is computed at fill time. If no fresh orderbook is available, every numeric field is a "0" placeholder and pricing_unavailable: true; callers MUST check that flag rather than rendering the zeros as a real quote. Supported exchange_id values: polymarket, kalshi, predictfun. Auth & scope. Requires trade:read.

GET

orders

fee-quote

curl --request GET \
  --url https://execution.kairos.trade/orders/fee-quote \
  --header 'X-Api-Key: <api-key>' \
  --header 'X-Api-Secret: <api-key>' \
  --header 'X-Client-Id: <api-key>'

import requests

url = "https://execution.kairos.trade/orders/fee-quote"

headers = {
    "X-Client-Id": "<api-key>",
    "X-Api-Key": "<api-key>",
    "X-Api-Secret": "<api-key>"
}

response = requests.get(url, headers=headers)

print(response.text)

const options = {
  method: 'GET',
  headers: {
    'X-Client-Id': '<api-key>',
    'X-Api-Key': '<api-key>',
    'X-Api-Secret': '<api-key>'
  }
};

fetch('https://execution.kairos.trade/orders/fee-quote', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://execution.kairos.trade/orders/fee-quote",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "X-Api-Key: <api-key>",
    "X-Api-Secret: <api-key>",
    "X-Client-Id: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://execution.kairos.trade/orders/fee-quote"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("X-Client-Id", "<api-key>")
	req.Header.Add("X-Api-Key", "<api-key>")
	req.Header.Add("X-Api-Secret", "<api-key>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.get("https://execution.kairos.trade/orders/fee-quote")
  .header("X-Client-Id", "<api-key>")
  .header("X-Api-Key", "<api-key>")
  .header("X-Api-Secret", "<api-key>")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://execution.kairos.trade/orders/fee-quote")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["X-Client-Id"] = '<api-key>'
request["X-Api-Key"] = '<api-key>'
request["X-Api-Secret"] = '<api-key>'

response = http.request(request)
puts response.read_body

{
  "avg_price_usdc": "0.52",
  "filled_size": "100",
  "requested_size": "100",
  "sufficient_liquidity": true,
  "notional_usdc": "<string>",
  "platform_fee_usdc": "<string>",
  "exchange_fee_usdc": "<string>",
  "venue_reserve_fee_usdc": "<string>",
  "total_fee_usdc": "<string>",
  "total_cost_usdc": "<string>",
  "pricing_unavailable": true,
  "is_estimate": true,
  "funding_tier": "t0_local",
  "bridge_fee_usdc": "<string>",
  "bridge_eta_p50_ms": 123,
  "bridge_eta_p95_ms": 123,
  "bridge_route_label": "<string>",
  "bridge_min_txs": 123,
  "bridge_eta_state": "measured",
  "bridge_quote_unavailable": true,
  "bridge_beta": true,
  "exchange_fee_note": "<string>"
}

{
  "error": "Unauthorized"
}

Authorizations

X-Client-Id

string

header

required

Credential client id (kairos_ck_...). Must be sent together with X-Api-Key and X-Api-Secret.

X-Api-Key

string

header

required

64-char hex API key.

X-Api-Secret

string

header

required

64-char hex API secret.

Query Parameters

exchange_id

enum<string>

required

One of polymarket, kalshi, predictfun.

Available options:

polymarket,

kalshi,

predictfun

Example:

"polymarket"

market_id

string

Condition id (Polymarket). Required for Polymarket if token_id is omitted.

token_id

string

CLOB token id (Polymarket) — preferred over market_id for book/fee lookup.

Example:

"71360012345678901234567890123456789012345678901234567890123456"

quantity

string

required

Decimal string. Number of shares/contracts to quote. Must be > 0.

Example:

"100"

side

enum<string>

required

The quote is side-aware (walks the ask side for buy, the bid side for sell).

Available options:

buy,

sell

Example:

"buy"

price

string

Decimal string in (0, 1]. Required when order_type=limit (the resting price). Omit for order_type=market to have the server price off the live book.

Example:

"0.52"

order_type

enum<string>

required

market (taker, priced from the book) or limit (maker, priced at price).

Available options:

market,

limit

Example:

"market"

Response

Combined platform + exchange fee quote.

Response for GET /orders/fee-quote. All numeric fields are decimal strings in USDC. The WebSocket subscribe_fee_quote stream emits a near-identical frame, but it omits venue_reserve_fee_usdc — do not treat the two as interchangeable. See execution-ws.asyncapi.yaml.

avg_price_usdc

string

required

Size-weighted executable price (VWAP for a market order), or the limit price for a limit order.

Example:

"0.52"

filled_size

string

required

Size the book can actually fill; equals requested_size when liquidity suffices.

Example:

"100"

requested_size

string

required

The size the caller asked to quote (echoes quantity).

Example:

"100"

sufficient_liquidity

boolean

required

False when the book cannot fill the full requested_size.

notional_usdc

string

required

filled_size × avg_price_usdc.

platform_fee_usdc

string

required

Kairos platform fee, based on the caller's fee tier. "0" if the tier lookup failed (fails open, never a phantom rate).

exchange_fee_usdc

string

required

Venue-specific fee the caller is expected to pay. "0" on venues that only charge takers when this quote is a resting maker order.

venue_reserve_fee_usdc

string

required

Fee the VENUE actually reserves to accept the order — distinct from exchange_fee_usdc. Some venues (Polymarket CLOB) can't know a resting limit will stay maker, so they reserve the taker estimate at placement regardless; buy-affordability checks must size off this field, not exchange_fee_usdc.

total_fee_usdc

string

required

platform_fee_usdc + exchange_fee_usdc.

total_cost_usdc

string

required

All-in cost — for a buy, notional + fees; for a sell, proceeds = notional − fees.

pricing_unavailable

boolean

required

true when no executable price was available (no client price and no fresh orderbook) — every other numeric field is a placeholder "0" and MUST NOT be rendered as a real quote.

is_estimate

boolean

required

Always true — this is a display estimate; the authoritative fee is computed at fill time.

funding_tier

enum<string>

required

Which rails run to fund this order. t0_local means no collateral moves; only t2_bridge carries a bridge fee. It names the movement, not whether the balance suffices.

Available options:

t0_local,

t1_prepositioned,

t2_bridge,

reject

bridge_fee_usdc

string | null

required

Bridge fee in USDC. "0" below t2_bridge, and null exactly when bridge_quote_unavailable is true — an unknown fee is never rendered as $0.00. This fee is already included in total_cost_usdc, and buy-affordability checks must include it too.

bridge_eta_p50_ms

integer | null

required

Median bridge fill time from Kairos's own completed intents, never a provider estimate. Present only once the route has ≥1,000 samples and its p90 ETA error is within ±10s.

bridge_eta_p95_ms

integer | null

required

95th-percentile bridge fill time from Kairos's own completed intents. Present under the same gate as bridge_eta_p50_ms.

bridge_route_label

string | null

required

The route in the user's words, naming the token the rail DELIVERS, e.g. "BNB USDT → Polymarket pUSD via Relay". Absent when nothing bridges.

bridge_min_txs

integer | null

required

On-chain transactions the bridge route needs, so a client can price the signing path. Absent when nothing bridges.

bridge_eta_state

enum<string> | null

required

Whether the ETA above is a measurement or an admission that the route has not earned one. Absent when nothing bridges.

Available options:

measured,

not_yet_measured

bridge_quote_unavailable

boolean

required

true when a bridge is needed and no quote landed. Consumers MUST render a "routing…" state and disable submit rather than showing any fee; bridge_fee_usdc is null in this state.

bridge_beta

boolean

required

true while tier-2 bridge funding is behind a flag, so the bridge row can be labelled beta.

exchange_fee_note

string | null

Human-readable note on the exchange fee, e.g. "1.8% taker fee".

Get a combined platform + exchange fee quote for a prospective trade

curl --request GET \
  --url https://execution.kairos.trade/orders/fee-quote \
  --header 'X-Api-Key: <api-key>' \
  --header 'X-Api-Secret: <api-key>' \
  --header 'X-Client-Id: <api-key>'

import requests

url = "https://execution.kairos.trade/orders/fee-quote"

headers = {
    "X-Client-Id": "<api-key>",
    "X-Api-Key": "<api-key>",
    "X-Api-Secret": "<api-key>"
}

response = requests.get(url, headers=headers)

print(response.text)

const options = {
  method: 'GET',
  headers: {
    'X-Client-Id': '<api-key>',
    'X-Api-Key': '<api-key>',
    'X-Api-Secret': '<api-key>'
  }
};

fetch('https://execution.kairos.trade/orders/fee-quote', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://execution.kairos.trade/orders/fee-quote",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "X-Api-Key: <api-key>",
    "X-Api-Secret: <api-key>",
    "X-Client-Id: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://execution.kairos.trade/orders/fee-quote"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("X-Client-Id", "<api-key>")
	req.Header.Add("X-Api-Key", "<api-key>")
	req.Header.Add("X-Api-Secret", "<api-key>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.get("https://execution.kairos.trade/orders/fee-quote")
  .header("X-Client-Id", "<api-key>")
  .header("X-Api-Key", "<api-key>")
  .header("X-Api-Secret", "<api-key>")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://execution.kairos.trade/orders/fee-quote")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["X-Client-Id"] = '<api-key>'
request["X-Api-Key"] = '<api-key>'
request["X-Api-Secret"] = '<api-key>'

response = http.request(request)
puts response.read_body

{
  "avg_price_usdc": "0.52",
  "filled_size": "100",
  "requested_size": "100",
  "sufficient_liquidity": true,
  "notional_usdc": "<string>",
  "platform_fee_usdc": "<string>",
  "exchange_fee_usdc": "<string>",
  "venue_reserve_fee_usdc": "<string>",
  "total_fee_usdc": "<string>",
  "total_cost_usdc": "<string>",
  "pricing_unavailable": true,
  "is_estimate": true,
  "funding_tier": "t0_local",
  "bridge_fee_usdc": "<string>",
  "bridge_eta_p50_ms": 123,
  "bridge_eta_p95_ms": 123,
  "bridge_route_label": "<string>",
  "bridge_min_txs": 123,
  "bridge_eta_state": "measured",
  "bridge_quote_unavailable": true,
  "bridge_beta": true,
  "exchange_fee_note": "<string>"
}

{
  "error": "Unauthorized"
}

Overview

Market Data API

Data API

Execution API

Agora Auction API

REST Guides

Market Data Guides

RPC Guides

RFQ Guides

WebSocket Guides

Krisis Guides

Get a combined platform + exchange fee quote for a prospective trade

Authorizations

Query Parameters

Response