Last Updated: 2026-10-26
A fast feed and an apparently stale quote do not establish a profitable trade. The quote may disappear before an order reaches it, the related contracts may settle differently, or the news may be wrong. The useful first project is an observation and replay study that separates information arrival, local processing and executable prices.
This is an engineering research guide, not a funded bot tutorial. It provides no measured Polymarket latency, infrastructure-region claim, minimum bankroll or expected return. All times, prices and costs below are synthetic.
Separate three different opportunities
Information trading: you receive news and estimate that a contract is underpriced. The estimate can be wrong. A higher price on another venue is evidence to investigate, not a hedge by itself.
Cross-venue payoff matching: you can describe positions whose combined payoff covers every relevant settlement state. This requires matching the exact event, deadline, source, cancellation and dispute rules. A candidate-win contract and a party-win contract are not interchangeable; a spot coin and a terminal-price binary do not have the same payoff.
A quoted price gap: a screen shows prices that would be attractive if available together. This is only an observation until size, fees, funding, account eligibility and both executions are established. A displayed gap is not an executed arbitrage.
Keep an auditable clock record
Record raw messages alongside normalized market and outcome identifiers, the rules version, sequence or snapshot identifiers when available, feed source and parser version. Preserve missing timestamps as missing rather than filling them with the current time.
Scroll sideways to see every column. Keyboard: focus the table region and use the arrow keys.
| Field | What it measures | Common mistake |
|---|---|---|
| Provider event time | The provider's timestamp for its specified event | Assuming it is the exchange matching time or synchronized with your clock |
| Local receive time | When your process receives the message | Calling the difference between unrelated clocks network latency |
| Decision duration | Local processing interval measured with a monotonic clock | Including an entire candle's age in the calculation |
| Hypothetical send time | A replay decision boundary | Treating a simulated send as a real order |
| Acknowledgment / fill / settlement | Different lifecycle observations, if actually recorded | Treating acknowledgment as a completed fill |
Suppose one feed message is received at local monotonic time 100 ms, a quote message at 180 ms, and the decision completes at 195 ms. The observed receive-time difference is 80 ms and processing after the quote takes 15 ms. You have not measured an 80 ms advantage at the matching engine: either feed could be delayed, and the quote could already have changed remotely.
Use a separate wall-clock timestamp for human-readable logs and cross-system alignment. Clock-offset estimates have uncertainty. Within one process, monotonic intervals avoid interpreting a wall-clock adjustment as negative processing time. Across hosts, do not subtract monotonic counters as if they shared an origin.
Reconstruct the book before simulating fills
Polymarket's real-time data documentation distinguishes book updates, price changes and last trades. A last trade is not the current executable ask. Pin the current protocol and outcome identifier instead of copying an old token or endpoint from a blog.
On a disconnect, sequence gap, unexplained timestamp jump or parser error, mark the reconstructed state unusable. Obtain an appropriate fresh snapshot and reconcile subsequent updates before resuming the study. Do not continue on the last good signal merely because it exists in memory.
Replay at the information actually available at each decision. Use quoted depth at the simulated arrival time, and label unknown queue position and cancellation races. An optimistic replay that fills every signal at the earlier best price is a sensitivity case, not a backtest of achievable execution.
A two-cent gap can disappear
Assume a synthetic completed round trip in the same claim: buy 100 shares at $0.54 and later sell them at $0.56. Gross cash gain is $2. With $1.40 total assumed execution costs, net gain is $0.60.
If the actual entry instead costs $0.57 while the exit remains $0.56, gross loss is $1, and net loss after the same costs is $2.40. Do not subtract a spread again if the actual buy and sell prices already include it. These costs are invented inputs, not a current venue fee schedule.
If only the purchase fills, the $56 sale proceeds do not exist. You hold 100 claims with unresolved exposure and must mark the open position separately. A cancel request can race with a fill. The order-management documentation describes checking orders and associated trades; a timeout is an unknown outcome to reconcile, not permission to submit a duplicate blindly.
Evaluate the study, including its failures
Report observations, eligible signals, rejected stale states, attempted simulations, assumed fills and unfilled cases as separate counts. Record every tested parameter set. Split development and evaluation by time and event; many quotes from one event are not many independent trials.
Measure receive-time distributions and gaps, not just the fastest example. Report net outcomes under several arrival delays, worse prices and partial-fill assumptions. Include unresolved positions and dependence between markets. A high win rate can coexist with losses if a few failures are large.
For a synthetic budget of $50 hosting, $120 licensed data and $20 storage per month, fixed cost is $190. At a constant $0.60 net per completed round trip before those fixed costs, at least 317 such round trips are needed to cover them. That calculation does not establish that 317 opportunities exist; losses, changing costs and taxes are not modeled. It is a feasibility check, not an earnings target.
Use permitted data sources and verify account and product eligibility directly. A VPN, self-attestation or changing location does not establish authorization to use a restricted product. Do not scrape against access restrictions or fund a trade to test this guide. A successful paper study still leaves independent execution, legal, security and risk review before any live system.
Sources: official data and order-management documentation checked 26 October 2026. No live feed benchmark or personal trading record is claimed. AITR may earn commissions from commercial links elsewhere; these documentation links are not affiliate recommendations. Trading can lose money.