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THE BRAINSTOCK API

The forecast API that grades itself.

One endpoint, the exact engine the site runs: a nightly-trained neural net reading price action, live news, long-horizon momentum and the market regime. Every response ships its own reliability report — walk-forward skill vs a naive baseline, a calibrated P(up), a conformal cone with measured coverage, and an earned-trust verdict that will flatly tell you to discount the call when the net has no edge on that ticker. No other forecast API tells you when not to trust it.

Graded in public
The same net whose every call is graded on the open track record — un-cherry-picked, receipts signed.
Calibrated, not confident
Cones whose coverage is measured out-of-sample. An 80% band that really contains the price ~80% of the time.
Honest about edge
Per-ticker earned trust: real-edge, weak-edge, or no-edge — and the forecast shrinks toward flat when trust is low.
Get a key
free · 100 calls/mo · no card
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Limits & plans
Free key
claimed here, no card
100 calls/mo
Pro key
upgrade here, or bundled with the Pro site plan
5,000 calls/mo
Max / enterprise
bundled with the Max site plan
50,000 calls/mo
Site plans manage keys from your account. Meters reset monthly. Auth: Authorization: Bearer yn_… or x-api-key.
GET/api/v1/forecast
?ticker=NVDA · ?horizon=1–20 (default 5) · ?engine=beta|classic (default beta)

Forecast path over the horizon plus the full reliability report. engine is neural-net once trained (baseline = transparent EWMA fallback), and trust.verdict ∈ real-edge | weak-edge | no-edge — build your integration to respect it.

curl "https://ynfinance.org/api/v1/forecast?ticker=NVDA&horizon=5" \
  -H "Authorization: Bearer yn_live_YOUR_KEY"
Response
{
  "ticker": "NVDA",
  "engine": "neural-net",
  "engineVariant": "beta",       // the default: the full 25-signal brain behind the site's stats
  "asOf": "2026-07-21",
  "price": 178.42,
  "target": 180.11,
  "movePct": 0.95,               // vs the MARKET — the brain never bets the tape
  "forecast": [ { "date": "2026-07-22", "price": 178.76 }, … ],

  "reliability": {                    // ← why this API exists
    "skill_score": 0.041,             //   walk-forward, vs a flat naive
    "directional_accuracy": 0.556,
    "dirProb": 0.55,                  //   calibrated P(beats the market)
    "coverage": 0.81,                 //   cone coverage, measured out-of-sample
    "cone": [ { "date": "…", "p10": 172.1, "p50": 180.1, "p90": 187.9 }, … ],
    "trust": { "weight": 0.56, "verdict": "weak-edge", "text": "…" },
    "regime": { "label": "calm regime", "stress": 0.12 }
  },

  "attribution": [ { "label": "Momentum", "contribution": 0.44 }, … ],
  "physics": [ … ],                   // no-opinion bootstrap cone
  "disclaimer": "…"
}
Data: nightly-trained BrainStock MLP · Yahoo/Finnhub/Stooq OHLCV (raced in parallel) · live news scoring · SPY regime context. 401 = bad key or monthly limit; 502 = data sources unavailable for that ticker. Educational research, not financial advice — the same disclaimer rides every response. Earlier experimental v1 endpoints still answer for existing integrations but are deprecated; this is the product.
Enterprise API
$1,995/mo · cancel anytime

For funds, fintechs and research desks. Everything in the standard API at institutional scale — plus the datasets nobody else can sell: the graded Bull Board book and the raw emission log — every forecast the model made, bullish and bearish, pre-selection, with features at emission — accumulated one public trading day at a time. Receipts are HMAC-signed at post time (tamper-evident vs post-hoc edits; verify via /api/provenance).

1,000,000 calls/mo
the full forecast API at institutional throughput
GET /api/v1/record
the graded Bull Board book — JSON or CSV, provenance hashes + signatures, lossless pagination
GET /api/v1/record/full
the raw emission log: every forecast pre-selection, bull AND bear, with the feature vector at emission
Priority support
direct line, integration help, custom terms available
custom quota or invoicing? api@ynfinance.org
The graded track record →The honesty calculator →Methodology →