Open for entriesprediction-market bots

Build a paper bot that creates trading volume.

Start with $10 of simulated cash. Complete as many buy-and-sell cycles as you can in 24 hours while keeping each loss small. We run the same paper test for every entry.

Prize

$500 first prize · additional YeNo rewards possible

Closes

Rolling qualification

Scored on

Cash after $1K volume

Benchmark

24-hour paper run

1BuildUse the starter brief.
2SubmitSend one version of your code.
3TestWe run the same published test.
4ScoreThe metric below sets your rank.

Download the starter kit ↓How scoring works →

Download the brief, run a sample, then follow the submission steps below.Download starter brief ↓

You submit code only. You do not deposit money, open a trading account, or place a real trade. Visit YeNo ↗ Submit your bot →

The challenge

Generate volume. Preserve capital. Keep trading.

Your agent starts with $10 in simulated cash. It buys, sells, and reuses that money for 24 hours. Reach $1,000 in completed volume while losing as little as possible to fees, spreads, and bad exits.

The reward

$500 + YeNo rewards

The highest-ranked qualifying bot wins $500. YeNo may offer additional rewards or pilot opportunities to selected bots under separate written terms. Entry is free and the competition is entirely online.

How it works

Start with working code. Make it better.

Download our bot, test your strategy, and send us a frozen build. We handle the market data, simulated trades, and scoring.

01Start free

Download a working bot

Start with our house bot and exact test contract. You can run everything locally without a YeNo account or trading capital.

02Build

Make the loop smarter

Improve when it buys, when it exits, and how much it risks. Run a full 24-hour simulation before submitting so you know it stays online and finishes flat.

03Submit

Send code, not money

Submit one frozen commit or container. Builderr runs it for 24 hours on unseen YeNo BTC market data and handles the cash, fills, fees, and scoring.

04Win

Cross $1,000 and finish flat

Bots that cross $1,000 of completed volume and finish with no open position qualify. The highest-ranked qualifying bot wins the YeNo-sponsored $500 prize.

Qualification

One exact contract.

The public rule, download, and machine evaluator use the same numbers.

✓The evaluator starts with exactly $10. You do not deposit or top up money, and the bot cannot borrow or use leverage.
✓Spend no more than $5 cash on any BUY, including protocol and platform fees.
✓Reach at least $1,000 in eligible executed volume within the 24-hour official run.
✓Finish with zero positions and no pending actions. There is no separate minimum ending-balance rule.
✓Hold at most one position or pending BUY at a time.
✓Use YeNo BTC five-minute Up/Down markets only.
✓Return valid decisions and reproduce from the submitted immutable commit or container digest.
✓Never self-trade, coordinate fills, or trade against another competition bot or entrant-controlled account.
✓Submit only your algorithm. The competition does not give you a trading account or place real orders for you.

Scoring

Complete cycles create volume. Nothing else does.

The bot cannot inflate its score with retries, order count, or unfinished inventory.

Eligible volume

executed BUY notional + executed SELL notional

$5.00gross BUY

$4.91gross SELL

$9.91credited after full exit

Rejected orders, cancellations, zero fills, settlements, redemptions, pending inventory, and incomplete exits add zero. Partial fills are combined into the same cycle.

RANK 1

Ending simulated cash

Among paper bots that reach $1,000 and finish flat, the highest simulated cash at the first clean crossing wins.

RANK 2

Maximum drawdown

If cash ties exactly, the bot with lower peak-to-trough drawdown ranks higher.

RANK 3

Time to target

If both still tie, the bot reaching $1,000 sooner ranks higher.

Starter kit

Working bot, exact contract, honest benchmark.

Use the code as a floor. Change the strategy, not the evaluator-owned cash or accounting.

These are development replay results, not official scores. None of the starter bots has qualified yet.

$559 median · $943 best

House Bot v1

Trades five-share BTC-reference moves near expiry, checks immediate exit depth, caps entry loss, and allows two cycles per market. This is the included code baseline.

$169 median · $762 best

Precision variant

Requires the order book to agree with the public BTC signal and aims for a small positive exit. It trades less often but gives builders a stricter starting point.

$168 median · $818 best

Aggressive reference variant

Uses the same signal family without the immediate-loss cap. It found more upside in some paths but was less reliable. The exact configuration is included for comparison.

Download everything (.zip) ↓House Bot v1 source ↓Tested configurations ↓Evaluator contract ↓

Development benchmark · Sep 22, 2026

The house bot got close. It did not qualify.

These results come from resampled recorded regimes used during development. They guide builders; they are not a forward qualification result.

$559median volume, all 30 paths

18/30paths finishing flat

$680median among flat paths

$943best flat path

No validation path crossed $1,000. Six of 30 reached at least $750. Under a two-cent adverse execution stress, the best run fell to $385 and the median to $70. The largest opportunities are better regime selection, execution timing, dynamic sizing, and guaranteed deadline flattening.

Benchmark meaning: $943 is the best observed development run—not an expected result, promise, or official score.

Build against this

One local endpoint. No account, deposit, or trading.

You submit only the algorithm. It never receives a key or controls a real ledger; it only returns HOLD, BUY, or SELL to the paper evaluator.

POST /decideJSON in · JSON out

// evaluator → your bot
{
  "market": { "id": "opaque", "secondsToClose": 84 },
  "account": { "cashUsd": 10, "eligibleVolumeUsd": 0, "position": null },
  "rules": {
    "maximumBuyCashUsd": 5,
    "targetVolumeUsd": 1000,
    "evaluationWindowHours": 24
  },
  "reference": {
    "btcMidUsd": 80482.155,
    "openingTargetUsd": 80444.946,
    "observedAt": 1789880823.619,
    "targetObservedAt": 1789880814.203,
    "targetProvisional": false
  },
  "books": {
    "YES": { "bids": [[0.49, 100]], "asks": [[0.50, 100]] },
    "NO":  { "bids": [[0.49, 100]], "asks": [[0.50, 100]] }
  }
}

// your bot → evaluator
{ "action": "BUY", "outcome": "YES", "maxCashUsd": 4.80 }

HOLD

Skip a weak, thin, stale, or late setup.

BUY

Choose YES or NO and a fee-inclusive cash ceiling.

SELL

Request a full exit; partial fills remain one cycle.

Submit a repository or HTTPS endpoint plus an immutable commit or container digest. Official runs block arbitrary outbound network access and record the exact input-data hash.

Reality model

A midpoint backtest will not pass.

The paper evaluator models the expensive and awkward parts of real execution so results are useful to YeNo.

Pay both fee layers

The evaluator applies the 1% YeNo overlay observed in our test account and the dynamic crypto taker fee, 0.07 × shares × price × (1 − price), on entry and exit.

Trade the later book

Every action waits 250 ms, then crosses a later L2 update for its own outcome. An opposite-side update cannot reuse a pre-decision quote.

Expect partial fills

Displayed depth, minimum order size, split exits, share dust, and executable one-sided books near expiry are modeled. A partial exit remains the same cycle.

Treat writes as ambiguous

A timeout is not permission to retry. Reconcile the venue first or risk opening a duplicate position.

Respect the clock

Books older than two seconds are rejected. New entries are blocked inside the final 15 seconds, and the account must be flat when the window ends.

Use causal reference data

Each request can include the public BTC midpoint, YeNo opening target, receive timestamps, and a provisional flag. Future-stamped target rows are excluded.

Protocol fee source: Polymarket's current fee documentation. It specifies the crypto rate, price curve, taker-only application, and five-decimal fee precision. The additional 1% overlay is modeled from observed YeNo test-account execution.

Market scope

BTC five-minute Up/Down only.

A narrow universe keeps market data, fills, and qualification comparable.

Hidden forward paper data

Qualification uses one unseen, receive-time-ordered 24-hour YeNo window. Recorded replay is for development, not the official score.

Code only—no real trading

Entrants submit an algorithm for paper evaluation. You do not fund an account, receive trading credentials, or place real orders.

Open for submissions

Start with our $943 bot. Build the first one that clears $1,000.

Submit your bot →