Stock Market Data API: A Buyer’s Technical Checklist
The questions a technical buyer should answer before building on a market-data provider.
Choose a stock market data API by matching the decision you need to power with the provider’s sources, latency, historical depth, identifiers, corporate actions, revision history, coverage reporting, redistribution rights, authentication, limits, exports, support, and price. A long endpoint list is not proof that the data behind every route is complete or licensed.
Start with product rights and source scope
Decide whether the use is internal analysis, application display, redistribution, model training, or execution. The same technically accessible row may have different permitted uses.
For live U.S. equities, ask whether quotes and trades are consolidated SIP, exchange-specific, delayed, or indicative. DataCedar does not claim real-time SIP coverage and focuses on historical and event research.
Inspect the historical contract
Require stable security identity, exchange calendar, timezone, corporate-action policy, corrections, expected-session coverage, deterministic pagination, and point-in-time event timestamps.
For filings and fundamentals, require SEC accessions and source concepts. For earnings and news, require revision and first-seen times. For transcripts, verify text ownership and historical completeness.
- Source and rights by stream
- First and last available date
- Known-at and revision model
- Gap and health endpoints
- Rate limits, plans, and overages
- Raw evidence and correction policy
Test the provider end to end
Run a fixed sample across mega-caps, ticker changes, delistings, splits, holidays, halts, filing amendments, schedule revisions, and missing data. Record latency and error behavior as well as values.
A good evaluation ends with a reproducible evidence pack and a clear rejection rule. DataCedar exposes coverage and rights states so clients can fail closed instead of interpreting every empty array as no event.
How DataCedar preserves the evidence
DataCedar separates acquisition from serving. Permitted source responses are retained with retrieval time and identifiers, normalized into DataCedar-owned tables, checked against expected coverage, and exposed through a stable versioned API. A collector can be replaced without changing the customer contract or making an upstream provider a runtime dependency.
Every research stream carries effective and known-at time where the distinction matters. Rights-restricted, unavailable, partial, stale, and genuinely empty states remain visible, so a backtest can fail closed and a buyer can see the product boundary before committing engineering time.
Key takeaways
- 01Match source rights to the intended product.
- 02Test history, identity, revisions, and gaps.
- 03Verify plan limits with real batch workloads.
- 04Demand evidence for corrections and normalized fields.
Query public company evidence through one stable API. Free Explorer tier, no card.
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