The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →A Polymarket bot is a repeating loop: choose a market and outcome, estimate that outcome’s probability, pass a risk gate, submit an order, track what happens to it, and reconcile the position after settlement. The sections below build that loop in the order it runs and mark which parts Polymarket’s official documentation defines.
What the engine needs before it can decide
The breakdown below is an engineering layout of the workflow Polymarket’s documentation describes. Polymarket does not prescribe this structure, and it does not make any particular strategy profitable. A working bot needs six components:
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- A market and outcome identifier, chosen to match the market’s protocol version.
- A probability estimate for that outcome, produced by your own signal or model.
- Current executable prices, plus the market’s tick size and minimum order size.
- Risk limits you set: position size, total exposure, minimum liquidity, and a maximum age for market data.
- An order policy that fixes order type, price, size, and expiration.
- A state store and reconciliation job that follows each order ID from submission through settlement.
Building the decision engine, stage by stage
Run the stages in order. Each one can stop a trade. A trade should be the output of several gates, not of a single signal.
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Find the market, confirm it is accepting orders, and select the outcome you intend to trade. Store the market’s protocol version with every trade record, because the identifier you pass depends on it. Polymarket’s quickstart uses token IDs for CTF (Conditional Token Framework) markets and position IDs for Polymarket Protocol V2 markets. The unified client uses the identifier you supply to select the matching exchange, signing domain, and approval route. A mismatch between identifier and market version is therefore a failure to test for explicitly, not one to assume away.
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2. Probability estimate and edge
Your engine converts information into a probability q that the outcome occurs. That estimate only means something when compared with a price you can actually trade at, not with a headline or the last traded price. A share priced at p implies a probability of p, so the edge on a buy is roughly q minus p, before fees and slippage.
Worked example: buying 100 shares at 0.40 costs 40 USDC. If the outcome occurs, each share pays 1.00, so the position returns 100 and the gross gain is 60 before fees. If your model says 0.55, the edge is 0.15 per share.
Polymarket’s FAQ describes outcome shares priced from 0.00 to 1.00 USDC, with the correct outcome paying 1.00 USDC per share. That page shows no publication date, and the quickstart refers to a pUSD balance. Confirm the collateral token and payout rules in the live documentation before relying on this arithmetic.
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The gate that acts on this comparison can be expressed as a single condition. The sketch below is illustrative logic, not an official API call:
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# Illustrative decision gate; field names are your own, not Polymarket's
def should_buy(q, ask, min_edge, position_after, max_position,
book_age_s, max_age_s, accepting):
return (accepting
and q - ask >= min_edge
and position_after <= max_position
and book_age_s <= max_age_s)
3. Risk and eligibility gate
Run every check again immediately before submission. A check made a few seconds earlier can already be stale. The gate should confirm that:
- the market is still accepting orders;
- the tick size and minimum order size used to build the order are current;
- the resulting position stays inside your per-market and total exposure caps;
- visible liquidity at your price covers the size you intend to trade;
- the order book and price data are younger than your maximum age;
- a global kill switch is not engaged.
The official pages establish market status and order constraints. Position caps, liquidity thresholds, data-age limits, and kill switches are design choices you make. They are not platform rules.
4. Order policy
The order policy turns a trade decision into a concrete order. For limit orders, two rules matter most. First, read the market’s current tick size and minimum order size. Second, a price that violates the current increment is rejected. Tick sizes can change, and the change can arrive through the market stream, so an order built from stale metadata can be refused.
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Suppose the current tick size is 0.01 (an illustrative value). A limit at 0.545 is then invalid. Re-price it to a valid increment only if the new price still clears your edge threshold. Otherwise, skip the trade. Rounding in the wrong direction can quietly erase your edge.
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Choose the order type from urgency and price tolerance, as the next section explains.
5. Execution-state handling
A successful submission is not a position. Store the returned order ID and status, then update the record as fills, delays, rejections, cancellations, and settlement arrive. Never resubmit an order only because its status is delayed. A retry without checking the first order can double your exposure.
6. Signing credentials and key handling
The quickstart reads the private key and wallet address from environment variables. Follow that pattern and keep both out of source files, version control, and logs. The documentation also links to session keys as an option for using a separate signer. Read the linked material on its scope before adopting that option.
Market orders, limit orders, GTC, and GTD
Choose the order type based on how urgently the trade must fill and how much price tolerance you have.
| Aspect | Market order | Limit order |
|---|---|---|
| Execution | Trades immediately against available liquidity | Specifies a price and fills at that price or better |
| Price control | Set by the liquidity available at submission; you do not name a price | You name the price you will accept |
| Rests unfilled | Not designed to rest on the book | Yes, until it fills, expires, or is canceled |
| Best when | Immediacy matters more than price | The acceptable price matters more than speed |
Limit orders also need a time-in-force setting. The two options below behave differently:
| Aspect | GTC (good till canceled) | GTD (good till date) |
|---|---|---|
| Stays open | Until filled or canceled | Until filled, canceled, or the expiration you set |
| Expiration | None set by you | Required; must be at least three minutes in the future |
| Security buffer | Not stated in the order guide | The order guide describes a one-minute security threshold, so the order lapses one minute before the expiration you enter |
| Use when | Your own process will cancel the order if conditions change | You want the order to lapse automatically at a known deadline |
Exact GTD timing is an implementation detail that can change. Confirm it on the live order page before deploying.
Reconciling the order lifecycle
Polymarket’s documentation separates four events: the order is accepted, the order is matched, the trade settles on-chain, and your position reflects the result. The quickstart states that settlement is asynchronous. The engine should therefore never infer a finished position from an accepted or matched order.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errors| Status | Meaning in the order flow | Engine action |
|---|---|---|
| live | Accepted and open; not yet filled | Keep tracking it; cancel or let it expire according to policy |
| matched | Trade executed; on-chain settlement still pending | Record the fill and wait for settlement before treating the position as final |
| delayed | Documented status; the order is not yet resolved | Poll until it resolves; do not resubmit |
| rejected | Refused, for example for an invalid price increment | Log the reason; rebuild the order from current market metadata before any retry |
After each settlement, run three checks:
- The sum of recorded fills for an order ID equals the matched size reported for that order.
- The position in your store matches the position reported after settlement. Investigate any gap before placing new orders in that market.
- Orders still live past their intended lifetime are canceled by policy, not left open by default.
A working integration is not a working strategy
Everything above shows that a bot can interact with Polymarket correctly. It can pick an outcome, respect price increments, submit orders, track their states, and check positions. It does not show that the bot should trade at all. Polymarket’s documentation does not validate a forecasting model, a signal, or a backtest, and it does not promise any return.
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The economics belong to your engine. They include fees, spreads, the gap between the price you see and the fill you receive, and the chance that your probability estimate is simply wrong. A backtest is only meaningful if it states its data period, includes fees and realistic fills, and is tested on data the model did not see while it was being built. Any performance figure you publish should come with that methodology and be labeled as your own work, not as an endorsement from the platform.
This guide does not cover current fees, rate limits, or the full market-data stream schema. Check Polymarket’s live developer documentation before designing around any of them.
Placing a first order: the documented sequence
The current quickstart follows this order. Test with a small size before trading the amount your model recommends.
Quick Recap
- Load the private key and wallet address from environment variables.
- Initialize the unified client with that signer and wallet address.
- Confirm that at least 10 pUSD is available. This is the quickstart’s recommendation for its sample order workflow, not a minimum account balance or a general trading requirement.
- Select the outcome identifier that matches the market’s protocol version.
- Submit a market order for the intended size.
- Store the returned order ID and status.
- Wait for settlement, following the lifecycle rules in the reconciliation section.
- Check the position and compare it with your order record.
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