Horizon + Limitless

Trade on Limitless, a prediction market on Base (chain ID 8453).

Limitless is a prediction market running on Base (chain ID 8453), a fork of Polymarket. Horizon supports the Limitless REST API with API key header authentication.

Quick Setup

hz.run(
    name="limitless_mm",
    exchange=hz.Limitless(
        api_key="...",
        private_key="0x...",
        owner_id="...",
    ),
    mode="live",
    ...
)

Credentials

Explicit

hz.Limitless(
    api_key="YOUR_API_KEY",
    private_key="0xYOUR_PRIVATE_KEY",
    owner_id="YOUR_OWNER_ID",
)

Environment variables

export LIMITLESS_API_KEY="..."
export LIMITLESS_PRIVATE_KEY="0x..."
export LIMITLESS_OWNER_ID="..."

hz.Limitless()  # reads from env

All three credentials are required for live trading:

• API key: authenticates REST requests via header
• Private key: Ethereum private key for on-chain order signing on Base
• Owner ID: your account/owner identifier on Limitless

Limitless Configuration

@dataclass
class Limitless:
    api_key: str | None = None
    private_key: str | None = None
    owner_id: str | None = None
    api_url: str = "https://api.limitless.exchange"

Field	Default	Description
api_key	None	API key for REST authentication
private_key	None	Ethereum private key for order signing (Base chain)
owner_id	None	Account/owner identifier
api_url	https://api.limitless.exchange	API base URL

Environment Variables

Variable	Description
LIMITLESS_API_KEY	API key
LIMITLESS_PRIVATE_KEY	Ethereum private key
LIMITLESS_OWNER_ID	Owner/account ID

Example Strategy

import horizon as hz

def predict(ctx):
    return hz.Quote(bid=0.40, ask=0.60, size=5)

hz.run(
    name="limitless_simple",
    exchange=hz.Limitless(),  # from env vars
    markets=["will-eth-hit-5000"],
    pipeline=[predict],
    mode="live",
)

Market Discovery

You can discover active Limitless markets using the standard discovery API:

markets = hz.discover_markets(exchange="limitless", limit=20)
top = hz.top_markets(exchange="limitless", limit=10)

Multi-Exchange

Limitless can be used alongside other exchanges in multi-exchange setups:

hz.run(
    name="cross_venue",
    exchanges=[hz.Polymarket(), hz.Limitless()],
    markets=["will-btc-hit-100k"],
    pipeline=[predict],
    mode="live",
)

Limitless runs on Base (chain ID 8453), not Polygon like Polymarket. Ensure your private key has funds on the Base network for order signing and settlement.