How to do one thing with market data
A task, the handful of cards in this catalogue that actually do it, and the part nobody mentions until it has already cost you an afternoon — the rate limit, the unadjusted price, the licence that turns a side project into a contract.
How to pull an economic data series
GDP, CPI, unemployment and rates are free from the agencies that compute them. The catch is revisions — today's series is not the one published then.
Next to Macro Data6 approachesUpdated
How to backtest an asset allocation over history
Five browser tools replay a fixed mix over past returns. What decides the number is the series before each fund existed, dividends, rebalancing and fees.
Next to Retirement5 approachesUpdated
How to backtest on a survivorship-free universe
Delisted stocks plus index membership by date, wired into Zipline, WealthLab or QuantConnect. What breaks is identity, not the engine.
Next to Backtesting6 approachesUpdated
How to calculate a portfolio's time-weighted return and XIRR
XIRR needs only dated cash flows and a closing value. A time-weighted return needs a valuation at every flow. The tools that compute each, and a script.
Next to Trackers5 approachesUpdated
How to check how much two ETFs overlap, and what a portfolio holds
Overlap by weight or by count, two funds or a whole portfolio, on holdings that may be a day or a quarter old. The tools, the arithmetic and what it misses.
Next to ETFs5 approachesUpdated
How to compare Social Security claiming ages in a planning tool
What five tools compute when you change a claiming age — benefit input, COLA, survivor rules, taxes, lifespan — and which assumptions move the result.
Next to Retirement5 approachesUpdated
How to download end-of-day prices for thousands of tickers at once
Ask for a date, not a ticker. A grouped-daily or bulk endpoint returns the whole market in one call; a yfinance loop returns 429s and quietly empty columns.
Next to Market Data6 approachesUpdated
How to download historical stock prices in Python
Three lines with yfinance, or a contract that will still work next quarter — and the split-and-dividend decision you have to make either way.
Next to Market Data5 approachesUpdated
How to export your broker trade history
The CSV in your broker's account menu is the ground truth. Getting it out is easy; making two brokers agree about what a trade was is the work.
Next to Journals6 approachesUpdated
How to get 13F holdings as data
The SEC's 13F data sets are seven free tab-separated tables. What the join gets wrong — amendments, a value column that changed units in 2023, and option rows.
Next to Insider & 13F5 approachesUpdated
How to get a historical exchange rate for a date
One formula gets an FX rate for a date. Choosing the rate — a central bank's fixing or a market close, which hour, what on a holiday — is the part that matters.
Next to Macro Data5 approachesUpdated
How to get a list of every US stock ticker, delisted ones included
Every US-listed ticker, the dead ones included — which free files stop at today's names, which go back years, and why a ticker is the wrong key to store.
Next to Market Data5 approachesUpdated
How to get an exchange trading calendar as data
Holidays, 1 p.m. early closes and session times as a table, from a library or an API — and why a calendar of trading days is not a calendar of settlement days.
Next to Analysis Libraries4 approachesUpdated
How to get analyst estimates, revisions and earnings surprises as data
Consensus EPS and revenue, how it moved, and actual against estimate, from a free key up — and why two sources' consensus and surprise rarely match.
Next to Fundamentals6 approachesUpdated
How to get earnings call transcripts as data
There is no free public source of earnings-call transcripts. Which APIs sell them, how fast they land, and the licence terms that decide what you may build.
Next to Fundamentals5 approachesUpdated
How to get pre-market, after-hours and overnight bars as data
Daily bars leave extended hours out of the price, minute bars may need a flag, and overnight bars are one venue's. Which APIs return which session, and how.
Next to Charting & Screeners6 approachesUpdated
How to get historical implied volatility and IV rank as data
A stock's IV is a series a vendor builds, not a field on an option. Which vendors sell it ready-made, how to build it from a chain, and where the numbers part.
Next to Options5 approachesUpdated
How to get a history of market cap and P/E, not today's snapshot
yfinance's info gives today's market cap and P/E. A history needs share counts as filed, carried forward between filings, or a vendor that did it daily.
Next to Fundamentals6 approachesUpdated
How to get historical options prices, expired contracts included
A live chain only lists today's contracts. Where daily and intraday prices for expired options come from, how far back, and what breaks when you join them.
Next to Options6 approachesUpdated
How to give an AI assistant your brokerage account
Read-only through a hosted connector, orders only through the broker's own server. Where an agent with order rights goes wrong, and why paper is not a setting.
Next to Account APIs5 approachesUpdated
How to replace yfinance in a script
Porting a yfinance script to a keyed API: the DataFrame changes shape, Close stops meaning the same thing, and the dates move. What to map, column by column.
Next to Market Data4 approachesUpdated
How to stream real-time stock quotes
Two free WebSockets will stream live US trades today. What they cost is not the subscription — it is which subscriber the exchange thinks you are.
Next to Market Data6 approachesUpdated
How to backfill years of minute bars
US minute history comes as a paginated API, a flat-file drop or a one-off CSV purchase. Adjustment, delisted tickers and the licence decide it.
Next to Market Data6 approachesUpdated
How to get an earnings calendar as data
Report dates as CSV or JSON, from a free key up — and what the rows leave out, which is whether a date is confirmed, the time of day and which quarter.
Next to Market Data5 approachesUpdated
How to get dividend history, ex-dates and yield into Google Sheets
GOOGLEFINANCE has no dividend fields. An add-on, a CSV endpoint for IMPORTDATA or a short Apps Script fills the gap, each with its own cost.
Next to Dividends4 approachesUpdated
How to get ETF holdings as data
Issuers publish ETF holdings daily, each in its own format; the SEC publishes them quarterly, two months late. Which to use, and what each one leaves out.
Next to Fundamentals5 approachesUpdated
How to get SEC filings as data
EDGAR hands you every US filing as JSON, free and keyless. What the XBRL endpoints hold, what they do not, and the rate limit that stops the naive loop.
Next to Fundamentals5 approachesUpdated
How to get short interest as data
FINRA publishes short interest for every US stock twice a month, free and keyless. The lag, the sentinel values, and why it is not daily short volume.
Next to Insider & 13F4 approachesUpdated
How to give an AI assistant market data
Claude Desktop, Cursor and Claude Code take one JSON block per MCP server. What breaks — the model spends your quota, reads your errors and misses stale data.
Next to MCP Servers6 approachesUpdated
How to record options trades in a trading journal
A spread imported as legs is scored as four trades, and an expiry often has no row. Which journals rebuild the position, and what you still fix by hand.
Next to Journals6 approachesUpdated
How to send TradingView alerts to a broker through a webhook
A relay turns a TradingView alert into an order. What breaks is the JSON, the bar the alert fires on, the duplicate, and a size meant for the chart.
Next to No-Code Trading5 approachesUpdated
How to store years of minute bars locally
Parquet and DuckDB, ArcticDB or a time-series server. What breaks is a re-run backfill that lands beside old rows, and bars stamped on two clocks.
Next to Tick Storage5 approachesUpdated
How to carry cost basis across a brokerage account transfer
The shares move in days; the cost travels on a separate statement, and older lots may not travel at all. What your tracker needs typed in, and when.
Next to Trackers5 approachesUpdated
How to import your broker's CSV into a portfolio tracker
Export transactions, not holdings, and pick a tracker that knows your broker's file. What breaks is quiet — splits counted twice, fees dropped, dates misread.
Next to Trackers6 approachesUpdated
How to reconcile wash sales across accounts and against your 1099-B
Each broker's 1099-B checks one account and one CUSIP; the rule covers all your accounts. Only one card computes the gap, and the second year is the trap.
Next to Trackers2 approachesUpdated
How to track foreign-currency dividends and the tax withheld from them
Every foreign dividend is three numbers and an exchange rate. Which trackers record withholding per holding, and why the rate you set is not the rate you paid.
Next to Dividends6 approachesUpdated
How to get insider trades (Form 4) as data
Every Form 4 is XML on EDGAR, free and keyless. What the flat files and the parsers get wrong — partial amendments, transaction codes and a 10b5-1 flag.
Next to Insider & 13F5 approachesUpdated
How to get split and dividend history as data
Corporate actions as their own table, with four dates per dividend and a ratio per split — and the spin-off that is neither, recorded three ways.
Next to Market Data5 approachesUpdated
How to get congressional stock trades as data
The House publishes a free index of STOCK Act filings; the trades are inside PDFs. What breaks — scans with no text, value bands, owner codes and late reports.
Next to Insider & 13F5 approachesUpdated
How to track dividend income across several brokers
One tracker as the ledger, each broker's dividend cash as the input. What breaks is one payment counted twice, and tax, DRIP and FX as separate rows.
Next to Trackers5 approachesUpdated
How to draw candlesticks in your own app
A candlestick chart is ten lines of JavaScript. Which library you may ship it in is a licence question — attribution, seats, and free builds that expire.
Next to Charting Libraries6 approachesUpdated
How to get an options chain
Free chains exist and are delayed and greekless. Paid ones start near thirty dollars — and under all of them sits one fee schedule.
Next to Options5 approachesUpdated
How to get fundamentals into a spreadsheet
Statements as cells that refresh, in Excel or Google Sheets — the add-ins, the APIs under them, and the licence that ends the moment you share the file.
Next to Fundamentals6 approachesUpdated
How to get news headlines as data
Ticker-tagged headlines start free. What you buy past that is a display licence, somebody else's entity classifier, and whatever archive your tier reaches.
Next to News APIs6 approachesUpdated
How to read a brokerage account from code
Positions, balances and transactions out of a consented brokerage account. Connecting takes a day; keeping the connection alive is the product.
Next to Account APIs6 approachesUpdated