polyrails

The Polymarket CLOB V2 execution layer that works.

Since the 2026 deposit-wallet migration, new accounts get 400 "maker address not allowed" / "invalid order version" from the legacy SDK paths most tutorials still show (py-clob-client-v2 #70 and friends). The working path is the official unified polymarket SDK over the gasless deposit-wallet flow — but wiring it correctly (EOA → derived API creds → AsyncSecureClient → setup_gasless_wallet → orders) is undocumented folklore.

polyrails is that folklore, packaged: private key in, working orders out.

import asyncio
from polyrails import Rails

async def main():
    r = await Rails.connect(private_key="0x...")      # no website, no manual API keys
    print(r.wallet, await r.balance())                # your V2 deposit wallet + pUSD balance
    res = await r.limit("TOKEN_ID", "BUY", price=0.42, size=10)
    print(res.ok, res.order_id)
    await r.close()

asyncio.run(main())

What it does

• Derives API credentials from your EOA — no dashboard visit needed.
• Binds your V2 Deposit Wallet (idempotent) and signs orders for it — the only order path the venue accepts for fresh accounts since July 2026.
• Limit (incl. post-only) + market (FAK/FOK) orders, cancels, open orders, balances.
• Market data: midpoint(), price(), spread(), book().
• Price ticks conformed automatically (BUY rounds up as a marketable ceiling, SELL rounds down — you never lose edge to a tick rejection).
• Attribution verification built in: builder_fills() returns the venue's own ledger of trades credited to a builder code.
• Clear, honest errors instead of cryptic 400s.

What it never does

• Never custodies keys or funds. Your key stays in your process, used only for local signing. There is no polyrails server. (The two biggest hosted Polymarket bots were hacked for −$70k and −$230k in 2026. Architecture is the fix: there is nothing here to hack.)
• Never places an order you didn't call for.

Funding disclosure

Orders placed through polyrails carry a builder attribution code — a public identifier in the signed order (that's Polymarket's official Builder Program). Attribution costs you nothing: polyrails sets no builder fee (0 bps, verifiable on-chain per order); the code only routes a share of Polymarket's builder rewards pool to whoever's code is attached. That's how free, non-custodial open source stays maintained.

Resolution order: Rails.connect(builder_code=...) → POLYRAILS_BUILDER_CODE env → the maintainer's code (polyrails, 0x7885f4b3b4c42bbee435fc16f66e7679b461610eb080c9985bdd9fdfd1bffd56). Registered builder? Pass your own code and keep the rewards. Want no attribution at all? Set builder_code="" (or env POLYRAILS_BUILDER_CODE=off).

Status

v0.1 — extracted from a private trading system and validated end-to-end on the live venue (order lifecycle + attribution CONFIRMED on the builder ledger; the whole validation cost $0.02). Gates and roadmap: GATES.md, CHANGELOG.md.

Install

pip install polyrails

Requires Python ≥ 3.11. MIT licensed.