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ThetaData

Already running a ThetaData Terminal? Connect it to Lavender Terminal and your option chain fills with live ThetaData quotes, volume, and open interest, right alongside Lavender's independently computed Greeks.

What you get

ThetaData serves live OPRA options data plus equity and index quotes from a ThetaData Terminal running on your machine. Connected to Lavender, it drives:

  • Live option quotes across the chain in the Montage — bid, ask, sizes, and quoting exchange
  • Volume and open interest per contract
  • Underlying data in the ticker header — quotes for stocks, the latest price for indices, and the day's open, high, low, and close with change

The Greeks and implied volatility you see in the Montage are always computed by Lavender's own engine, independent of the data feed.

Connect it

  1. In Settings → Data Feed, select ThetaData and enter your email and password.
  2. Restart for the change to take effect.

Lavender uses a ThetaData Terminal already running on your machine, or starts one for you with your credentials. (ThetaData Terminal needs Java 17 or later; Java 21 or later is recommended.)

Runs locally

Lavender talks to the ThetaData Terminal over localhost. Your credentials are stored on your machine (obfuscated) and are used only to start and authenticate that local terminal — they are never sent to Lavender.

How data arrives

ThetaData speaks two protocols, and Lavender uses both:

  • Snapshot requests (REST) — request/response over HTTP. Any number of applications can make snapshot requests at the same time without affecting each other.
  • Live streaming (websocket) — a single streaming connection per terminal. If another application starts streaming from your ThetaData Terminal it takes over the stream, and starting Lavender's stream takes it back. Snapshot requests keep working throughout.

Run one streaming application against a given ThetaData Terminal at a time; snapshot requests from any number of tools run side by side.

Data types

Terminal subscribes to the data types your ThetaData plan covers: options, stocks, and indices.

Auto-detect is on by default: at startup Terminal checks which types your credentials entitle and subscribes to those — the Settings panel shows the result (for example, Detected: stocks + index + options).

Prefer to choose yourself? Turn Auto detect subscription off and pick the types by hand. At least one type stays selected.

See also