{
  "error": "INSUFFICIENT_BALANCE",
  "message": "Account balance $12.50 insufficient for order cost $25.00"
}

// 402 UPGRADE_REQUIRED — feature_key + upgrade_url at the root
{
  "error": "UPGRADE_REQUIRED",
  "feature_key": "wallets.sandbox_baseline",
  "upgrade_url": "/pricing"
}

// 403 ACCESS_RESTRICTED (not on the allowlist / flagged account)
// + headers: X-Polysim-Code: ACCESS_RESTRICTED
{"error": "ACCESS_RESTRICTED", "message": "API access restricted. Contact support to request access."}

import time

code = response.headers.get("X-Polysim-Code")
if code in {"TRADE_IN_PROGRESS", "SERVER_BUSY"}:
    time.sleep(int(response.headers.get("Retry-After", "1")))
    # Repeat the original request with the SAME client_order_id.
elif code == "DEADLINE_OVERSHOT_BUT_PERSISTED":
    order_id = response.headers["X-Polysim-Order-Id"]
    source = response.json().get("source")
    # Do not POST again. Poll by id only for a pending row; otherwise scan
    # GET /v1/orders and match the original client_order_id.
elif code == "PERSISTENCE_UNKNOWN":
    # Do not POST again until GET /v1/orders confirms no matching order.
    pass

# Wrong — naked short on the "Down" side:
sell_down = post("/v1/order", json={"token_id": down_tok, "side": "SELL", "quantity": 100, "price": 0.51})
# → 400 INSUFFICIENT_POSITION (you don't hold any Down shares)

# Right — buy both sides instead. Up + Down ≈ 1.00, so total notional is similar
# to a two-sided quote, and you keep the spread on whichever side fills first:
buy_up   = post("/v1/order", json={"token_id": up_tok,   "side": "BUY", "quantity": 100, "price": 0.49})
buy_down = post("/v1/order", json={"token_id": down_tok, "side": "BUY", "quantity": 100, "price": 0.49})

# Handle key-issuance refusals. Branch on `X-Polysim-Code`;
# the body's `error` field holds the human message.
resp = requests.post(f"{BASE_URL}/v1/keys", headers={"X-API-Key": KEY}, json={"name": "bot"})
if resp.status_code == 403:
    code = resp.headers.get("X-Polysim-Code")
    if code == "TIER_REQUIRES_UPGRADE":
        # Paid tier / "admin" requested, or "trade" on an expired paid grant.
        print("Requested tier or permission needs an upgrade — https://polysimulator.com/pricing")
    elif code == "CLOSED_BETA":
        print("Issuance temporarily closed — retry later or contact support")
    elif code == "API_PRO_COMING_SOON":
        print("Residual rollout code — check /account/billing")

import asyncio
import aiohttp

async def resilient_ws(url, token, market_ids):
    """WebSocket connection with automatic reconnection."""
    backoff = 1
    while True:
        try:
            async with aiohttp.ClientSession() as session:
                async with session.ws_connect(f"{url}?token={token}") as ws:
                    backoff = 1  # Reset on successful connect

                    await ws.send_json({
                        "action": "subscribe",
                        "markets": market_ids,
                    })

                    async for msg in ws:
                        if msg.type == aiohttp.WSMsgType.TEXT:
                            handle_message(msg.data)
                        elif msg.type == aiohttp.WSMsgType.CLOSED:
                            break
                        elif msg.type == aiohttp.WSMsgType.ERROR:
                            break

        except Exception as e:
            print(f"WS error: {e}")

        wait = min(backoff, 30)
        print(f"Reconnecting in {wait}s...")
        await asyncio.sleep(wait)
        backoff *= 2