A stock forecast API is only useful if you can trust what it says it does. Quantustik's public v1 REST API for S&P 500 signals and forecasts is documented by a machine-readable OpenAPI schema you can fetch and diff yourself — the schema is the artifact, not a marketing claim about it.
The public v1 REST API exposes read-only endpoints for current and historical signals per ticker, full quantum-model forecast probabilities across multiple horizons, market-conditions classification, a fear/greed snapshot, cross-ticker correlations, earnings-calendar context, and the backtested track record. Every endpoint returns plain JSON — no SDK lock-in, no proprietary query language.
The v1 REST endpoints are openly documented and readable without an account for light use. Higher-throughput access — for a bot, a backtest sweep, or a production integration — is where a key and a tier matter, and where the server's own quota mechanics apply (a response header reports how much headroom you have left). We are deliberately not printing a specific quota number on this page: tiers and limits are live configuration on the developers page, and a number frozen into an article copy would go stale the next time they change. The MCP server (for AI agents) is a separate access path over the same underlying data, with its own auth story — see the MCP-focused articles in this lab for that.
The live schema at /api/v1/openapi.json is generated straight from the running API, so it can never describe a field or a status code the real endpoint doesn't actually have. That makes it the right thing to point a codegen tool, an API client, or a skeptical developer at — instead of trusting prose on a landing page about what the API supposedly does.
This matters more for a forecasting API than a typical CRUD API: a schema that promised more than the live service delivers would be a trust problem, not just a documentation bug. Treat any claim on this page that isn't reflected in the schema or the developers page as unverified.
Every data-returning endpoint is a GET — there is no way to place, modify, or cancel a trade through this API, and no such feature is planned as part of it. The one non-GET route on the API accepts inbound alert webhooks (e.g. from a charting platform) for internal signal processing; it is not a mechanism for a client to write back to their own account or execute anything.
The API is read-only by design: it returns data, it never executes a trade. What's keyless versus metered, and the exact quota per tier, is deliberately not restated here with hard numbers, because those change — the OpenAPI schema and the developers page are the source of truth, not this page. An API response is only as good as the quantum forecast behind it: see the calibration page for what the model itself is actually shown to get right.
Educational research only — not investment advice.