Actions

Answer the current step (signature or wallet result)

Posts the wallet’s answer to the step that is needs_signature and returns the next step.

Signature steps (eth_signTypedData_v4, personal_sign): send {"signature": "0x…"} — exactly 65 bytes, hex. A JSON string in result is accepted as the signature too. Smart-account (EIP-1271) signatures are refused.
wallet_sendCalls steps (Predict.fun approvals): send {"result": <the wallet_sendCalls return value>}, or {"result": ["0xhash", …]} after sending fallbackRequests one by one. The step moves to working while Kairos waits for the approvals on chain.

Failures after a signature are not HTTP errors. A venue refusal, an expired signing window, a rate limit or an ambiguous submission comes back as 200 with status: "failed", error, and — when there is one — errorCode. Read errorCode before retrying: ORDER_OUTCOME_UNKNOWN and CANCEL_OUTCOME_UNKNOWN mean the venue may have acted, so read /v3/wallets/{address}/orders before placing again.

Safe to repeat. Posting to a step that is no longer needs_signature returns the current step unchanged; a step is never run twice. A wrong signer gets 400 and the same step stays open for another try.

This call waits up to about 45 s for the step to settle, then returns working; keep polling GET /v3/actions/{id}.

POST

actions

{id}

curl --request POST \
  --url https://execution.kairos.trade/v3/actions/{id} \
  --header 'Content-Type: application/json' \
  --header 'X-Kairos-Partner-Id: <api-key>' \
  --header 'X-Kairos-Wallet-Api: <x-kairos-wallet-api>' \
  --data '
{
  "signature": "0x4f8b2c1d9e7a6b5c4d3e2f1a0b9c8d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c3d9e8f7a6b5c4d3e2f1a0b9c8d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c0d9e1b"
}
'

{
  "id": "6a1f9e2c-3b4d-4c5e-8f6a-7b8c9d0e1f2a",
  "type": "order",
  "status": "failed",
  "request": null,
  "description": null,
  "chainId": null,
  "venue": null,
  "result": null,
  "error": "the signing window closed before a signature was accepted; nothing was placed; start a new action",
  "errorCode": "SIGNATURE_EXPIRED"
}

Authorizations

X-Kairos-Partner-Id

string

header

required

Wallet API partner id, issued by Kairos together with the partner's base URL. Identifies the partner (tenant) on every /v3 call; sent instead of an API key. Letters, digits and ._:-, at most 64 characters, case-insensitive. A partner id issued for an individual account cannot be sent this way — that account sends its API key triple instead.

Headers

X-Kairos-Wallet-Api

enum<string>

required

Wallet API contract version. Send 2 — the multi-venue contract this reference documents. Without the header (or with any other value) /v3/actions and /v3/wallets/* serve the original Polymarket-only contract, which ignores venue prefixes, expiresAt and setup.venues, omits chainId, venue and fallbackRequests from steps, refuses orders on a wallet that is not set up (409), and returns snake_case order and position rows.

Available options:

2

Path Parameters

string<uuid>

required

Action id returned by POST /v3/actions.

Body

application/json

Answer to a needs_signature step. Send signature for signature prompts (65 bytes, hex, 0x optional); a JSON string in result is read as the signature. For wallet_sendCalls, send the wallet's return value (or the transaction hashes from fallbackRequests) as result.

signature

string

65-byte ECDSA signature, hex (0x optional).

Pattern: ^(0x)?[0-9a-fA-F]{130}$

Example:

"0x4f8b2c1d9e7a6b5c4d3e2f1a0b9c8d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c3d9e8f7a6b5c4d3e2f1a0b9c8d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c0d9e1b"

result

any

The wallet's return value for wallet_sendCalls, or an array of transaction hashes.

Response

The next step — needs_signature (another prompt), working, done, or failed (with error and usually errorCode).

The current step of an action. Every response from /v3/actions and /v3/actions/{id} is one of these.

string<uuid>

required

Action id. One id for the whole action, across venues.

type

enum<string>

required

Available options:

setup,

order,

cancel,

login

status

enum<string>

required

needs_signature — run request and answer; working — poll; done — read result; failed — read error and errorCode.

Available options:

needs_signature,

working,

done,

failed

request

object | null

required

What the wallet must run. Non-null only while needs_signature.

Show child attributes

Example:

{
  "method": "personal_sign",
  "params": [
    "0x6b6169726f732e7472616465207761…",
    "0x8ba1f109551bD432803012645Ac136ddd64DBA72"
  ]
}

description

string | null

required

Text to show with the wallet prompt (e.g. Confirm this Hyperliquid order), or progress text while working.

chainId

string | null

required

EIP-155 chain id (hex) the wallet must be on to answer — 0x89 Polygon, 0x38 BNB Chain, 0xa4b1 Arbitrum One (0x66eee Arbitrum Sepolia on Hyperliquid testnet). null for personal_sign and when nothing is asked.

Example:

"0x38"

venue

enum<string> | null

required

Venue of the current prompt; null when finished and on cancels.

Available options:

polymarket,

predictfun,

hyperliquid

result

object

required

Outcome on done (and the provisional outcome of a held order). Shape depends on type.

Option 1
Option 2
Option 3
Option 4

Show child attributes

Example:

{
  "ready": false,
  "venues": {
    "polymarket": {
      "ready": true,
      "tradingWallet": "0x2f9c4b8e1d7a6c5b4a3f2e1d0c9b8a7f6e5d4c3b",
      "transactionHash": "0x7c3e9a1b5d2f4c6e8a0b2d4f6a8c0e2b4d6f8a0c2e4b6d8f0a2c4e6b8d0f2a4c"
    },
    "predictfun": {
      "ready": false,
      "next": "fund",
      "tradingWallet": "0x8ba1f109551bd432803012645ac136ddd64dba72",
      "venueDetail": {
        "reason": "needs about 0.0004 BNB on BNB Chain to pay gas for 2 Predict.fun approvals",
        "approvals": 2,
        "gasWei": "400000000000000"
      }
    }
  },
  "tradingWallet": "0x2f9c4b8e1d7a6c5b4a3f2e1d0c9b8a7f6e5d4c3b",
  "transactionHash": "0x7c3e9a1b5d2f4c6e8a0b2d4f6a8c0e2b4d6f8a0c2e4b6d8f0a2c4e6b8d0f2a4c"
}

error

string | null

required

Why the action failed; non-null on failed.

fallbackRequests

object[]

Present with wallet_sendCalls requests only — the same calls as individual eth_sendTransaction requests, for wallets without EIP-5792. Send them in order and answer with {"result": ["0xhash", …]}.

Show child attributes

expiresAtMs

integer<int64>

Last accepted millisecond (Unix ms) for answering this prompt. Answers after it fail the action with SIGNATURE_EXPIRED.

Example:

1793130772999

holdUntilMs

integer<int64>

On a working order the venue is still matching — poll again after this time (Unix ms). result then holds a provisional outcome with final: false.

errorCode

enum<string>

Machine-readable reason on a failed step; the key is omitted when the failure has no code. Codes may be added; treat an unknown code as a failure whose order was not placed.

Code	Meaning	Order placed?
`NO_MATCH`	An immediate order (FOK/FAK/IOC) found nothing to match.	No
`VENUE_REJECTED`	The venue refused the order.	No
`ORDER_OUTCOME_UNKNOWN`	The submission's outcome is unknown. Read the wallet's orders before placing again.	Maybe
`CANCEL_OUTCOME_UNKNOWN`	Some venue may have cancelled. Read the wallet's orders.	Maybe
`SIGNATURE_EXPIRED`	The signing window closed before a signature was accepted. Nothing was sent.	No
`CLIENT_ORDER_ID_CONFLICT`	The `clientOrderId` names an order with different terms.	No
`HYPERLIQUID_AGENT_MISSING`	Hyperliquid no longer lists this wallet's trading approval. Run `setup` again.	No

Available options:

NO_MATCH,

VENUE_REJECTED,

ORDER_OUTCOME_UNKNOWN,

CANCEL_OUTCOME_UNKNOWN,

SIGNATURE_EXPIRED,

CLIENT_ORDER_ID_CONFLICT,

HYPERLIQUID_AGENT_MISSING

curl --request POST \
  --url https://execution.kairos.trade/v3/actions/{id} \
  --header 'Content-Type: application/json' \
  --header 'X-Kairos-Partner-Id: <api-key>' \
  --header 'X-Kairos-Wallet-Api: <x-kairos-wallet-api>' \
  --data '
{
  "signature": "0x4f8b2c1d9e7a6b5c4d3e2f1a0b9c8d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c3d9e8f7a6b5c4d3e2f1a0b9c8d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b1c0d9e1b"
}
'

{
  "id": "6a1f9e2c-3b4d-4c5e-8f6a-7b8c9d0e1f2a",
  "type": "order",
  "status": "failed",
  "request": null,
  "description": null,
  "chainId": null,
  "venue": null,
  "result": null,
  "error": "the signing window closed before a signature was accepted; nothing was placed; start a new action",
  "errorCode": "SIGNATURE_EXPIRED"
}

Get started

Onboard users

Trade

Route and fund

Partner fees

Build

Endpoints

Answer the current step (signature or wallet result)

Authorizations

Headers

Path Parameters

Body

Response