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ThetaData

ThetaData Streaming WebSocket API

JSON WebSocket streaming of US stock trade/quote, options trade/quote, and index price streams, served locally by the Theta Terminal at ws://127.0.0.1:25520/v1/events. Requires a paid subscription with streaming permissions; a single connection per user is permitted, with CONNECTED/DISCONNECTED status headers and QUOTE/TRADE/STATUS message types.

Documentation Provider Profile APIs.io AsyncAPI GitHub

ThetaData Streaming WebSocket API is one of 7 APIs that ThetaData publishes on the APIs.io network, described by an AsyncAPI event-driven specification.

Tagged areas include Streaming, WebSocket, Trades, Quotes, and Real-Time. The published artifact set on APIs.io includes API documentation and an AsyncAPI specification.

This event API exposes 0 operations across 1 channel, and defines 5 schemas. It is described by AsyncAPI 3.0.0, at version v1.

The API connects through a single server, 127.0.0.1:25520 (ws).

0 operations 1 channels 5 schemas

Metadata

The identity and technical contract details declared by the specification.

Specification
AsyncAPI 3.0.0
API Version
v1
Base URL
ws://127.0.0.1:25520/v1/events

Messages & Schemas 5

The contract defines 5 schemas that model the data carried by its messages. The most detailed are contract (5 properties), header (2 properties). Each schema is shown below with its type and property counts.

status
message
Keep-alive sent every second with terminal-to-FPSS connectivity status.
quote
message
NBBO quote event for a subscribed contract.
trade
message
Trade event for a subscribed contract.
header
object
Present on every message; describes type and connectivity status.
2 properties
contract
object
Present on QUOTE and TRADE messages. For options, strike is in 1/10th of a cent ($140 strike = 140000).
5 properties

Specification

The full machine-readable AsyncAPI contract behind this narrative.

Source

thetadata-streaming-asyncapi.yml Raw ↑

Other APIs ThetaData publishes across the network.

ThetaData MCP Server
AE Profile APIs.io
ThetaData Calendar API
AE Profile APIs.io
ThetaData Index API
AE Profile APIs.io
ThetaData Interest Rate API
AE Profile APIs.io
ThetaData Option API
AE Profile APIs.io
ThetaData Stock API
AE Profile APIs.io
#Streaming#WebSocket#Trades#Quotes#Real-Time
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API Details
ID
thetadata:thetadata-streaming-websocket-api
Base URL
ws://127.0.0.1:25520/v1/events
Docs
https://docs.thetadata.us/Streaming/Getting-Started.html
Provider
ThetaData
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This is an independent, third-party profile of ThetaData Streaming WebSocket API, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.

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