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Binary Outcome EV (No Side) Calculator
x402
Binary Outcome EV (No Side) Calculator is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).
Computes the expected value of a 'No' position in a binary prediction market given stake, true probability, and current market price.
Price / call$0.001
Success—
StatusUnknown
How this service works
Expected value of buying binary NO at (1−yes_price) under true_prob. Call when checking the NO side when YES is mispriced the other way. Returns EV per $1 notional on NO as deterministic JSON for $0.001 USDC via x402 on Base. First-party local math only—no RPC, live market feed, API keys, storage, or mediagen. Advisory only; the caller owns capital, risk, and production controls.
Output
Returns a JSON object containing the computed expected value (ev, which can be negative), the stake echoed back, the number of No shares purchased, the effective no_price, and a schema identifier string (delx/util-binary-ev-no/v1).
Example use cases
Pre-trade EV check on prediction market
“I'm looking at a binary prediction market where I think the true probability of the event is 30%, the No price is 0.55, and I want to stake 200 units — what's the expected value of taking the No side?”
Evaluating edge before scalping No contracts
“Before I place a No bet of 500 units on this market, can you calculate my EV? My true probability estimate is 40% and the current market no_price is 0.48.”
Sanity-checking a small No position
“I want to put 50 units on the No side of a binary market where I believe the true odds are 25% and the market is pricing No at 0.60 — is there positive EV here and how many shares would I get?”
Technical details
Endpoint
POSThttps://api.delx.ai/api/v1/x402/binary-ev-noWhen to prefer
Use this endpoint when you need a fast, cheap ($0.001 USDC) server-side computation of the expected value for the No side of a binary prediction market position. Prefer it over local calculation when you want a canonical, versioned result with a schema identifier for logging or auditing, or when the computation needs to be part of an x402-powered agent workflow.
Side effects
- Missing required fields (stake, true_prob, market_price) return a 400 validation error
- Probability values outside [0,1] range may return an error or nonsensical EV
- market_price of 0 or 1 causes division issues or degenerate results
- Non-integer stake may be rejected or silently coerced
- Payment failure or insufficient USDC balance returns a 402 error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| stake | integer | Input field: stake. |
| true_prob | number | Input field: true prob. |
| market_price | number | Input field: market price. |
Output
Schema · Response
{
"type": "json",
"example": {
"ev": -13.46153846153848,
"stake": 100,
"schema": "delx/util-binary-ev-no/v1",
"shares": 192.3076923076923,
"no_price": 0.52
}
}Tags
x402
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