Developer Blog
Technical guides for developers building on the StockFit API. XBRL parsing, point-in-time data, backtesting patterns, and SEC EDGAR engineering notes.
Best Fundamentals APIs in 2026 (8 APIs Compared)
The best fundamentals APIs in 2026, compared on free tier, pricing, coverage, and SEC audit trail: StockFit, FMP, EODHD, Alpha Vantage, and more.
Accurate Earnings Dates API: Predict, Then Confirm
How StockFit gets earnings dates right: predict from each issuer's SEC filing cadence, then confirm the next 28 days against Nasdaq-based exchange data.
Daily ETF Holdings: Six File Formats, One API
One daily ETF holdings API across six issuer file formats (csv, xlsx, xls, json, html, pdf), covering 2,200+ funds, far fresher than quarterly N-PORT.
Executive Compensation API: CEO Pay vs Performance
CEO and named-officer pay from SEC DEF 14A proxies as JSON: reported pay vs Compensation Actually Paid, pay-versus-performance, charted across sectors.
SEC EDGAR Data: Unlocking Alternative Insights for Quants
The unconventional alternative data signals hiding in SEC EDGAR: segment operating margins, Compensation Actually Paid, activist 13D filings, fund flows.
Beneficial Ownership API for Schedule 13D and 13G Filings
Pull Schedule 13D and 13G beneficial ownership from SEC EDGAR as JSON. Every 5% stake carries its accession number, point-in-time, activist or passive.
Point-in-Time Data: Essential for Backtesting Accuracy
How lookahead bias from restated financials, survivorship bias, and reporting lag corrupt backtests, and how point-in-time SEC fundamentals fix them.
Mapping CIK to Fund Tickers: A Practical Guide
Mapping a fund's CIK to its ticker is brutally hard: the SEC submissions feed carries none, company_tickers_mf.json lags months, and tickers get recycled.
Extract EPS and Share Count Using Arelle Efficiently
Extract EPS and weighted-average share count from XBRL with Arelle, plus the as-converted fix for multi-class filers like Visa a naive extractor misses.
Revenue Segmentation API: Revenue by Geography & Product
Revenue Segmentation API: revenue split by geography and product, period by period, parsed from XBRL dimensional facts in 10-K, 10-Q, and 20-F filings.
Company Peers API: Accurate Comparable Companies
The Company Peers API returns up to 6 same-industry comparable companies, ranked by revenue and classified by our SFIC system, one call per ticker.
Executive Officers API: Access Company Leadership Data
Get a company's current CEO and executive officers, with titles, from the Executive Officers API, built from SEC Form 3/4/5 insider filings.
ChatGPT App for Stock Fundamentals and SEC Data
The StockFit app is live in ChatGPT: ask about earnings, financial statements, insider trades, and ETF holdings, all answered from SEC EDGAR filings.
Fundamental Stock Analysis: A Comprehensive Overview
How investors use fundamental stock analysis to value companies, screen stocks, and build conviction, plus the financial data inputs behind every step.
Insider Cluster Buys: What You Need to Know for Success
Does the insider cluster buy signal beat the market? We tested 45 discretionary S&P 500 clusters from 2018 to 2024 against SPY using Form 4 data.
Earnings Calendar API: Developer Guide
The StockFit Earnings Calendar API: upcoming earnings dates, consensus EPS estimates, and report times across US issuers, plus EPS history and 8-K prints.
Understanding SEC Forms: A Guide to 10-K and More
Where the income statement, balance sheet, and cash flow statement live in a Form 10-K, plus 17 more SEC filings that power the StockFit API.
StockFit vs Alpha Vantage: API Fundamentals Comparison
StockFit API vs. Alpha Vantage for fundamentals: a side-by-side look at standardized statements, raw XBRL, filings access, insider data, ETFs, and pricing.
ETF Analysis: Free-Tier to Forensic Techniques Explained
Walk SPY end-to-end with the StockFit fund endpoints: profile, holdings, flows, overlap, fund health, and fee analysis from N-PORT and N-CEN filings.
Stock Backtesting with the Holy Grail API
Look-ahead bias is the silent killer of quant backtests. StockFit ships a per-fact, per-amendment audit trail, a true point-in-time ledger you can rewind.
Sector Metrics: StockFit vs Financial Modeling Prep
Why a single key-metrics shape fails for banks, insurers, and REITs, and how StockFit returns the right metrics for each business model.
StockFit vs. sec-api.io: Financial Data Conversion Explained
How the two products approach XBRL-to-JSON conversion, insider trading data, and developer ergonomics. Verified facts on both sides, no vendor spin.
XBRL Financials to JSON: Guide for Backtesting
Why SEC XBRL is hard to use directly, what "as-reported" really means, and how to assemble a clean point-in-time dataset for systematic strategies.
Build with the StockFit API
Every code example in these guides hits the same endpoints you get on the free tier. Get your API key and start shipping.