websocket streaming

WebSocket streaming pushes price updates to the client over a persistent connection instead of polling a REST endpoint.

Both commercial vendors in this slice offer it for real-time delivery: EODHD lists WebSocket streams among its formats, and Tiingo pairs its REST API with a WebSocket feed fed by IEX realtime data.

In this catalog it appears concretely: - EOD Historical Data APIs - data_format. - Tiingo Financial Data API - short_description — "REST and WebSocket API for end-of-day and real-time equity prices". - Massive - data_formats — "JSON, CSV, WebSocket stream, S3 flat files, SQL". - Tiingo - — "tick-level streaming for IEX/crypto/forex/BOATS".

Tiingo Financial Data API - short_description is the second reference point worth knowing: "REST and WebSocket API for end-of-day and real-time equity prices". Reading the two together shows how much variation sits underneath one shared label.

Access method sets your maintenance bill. Delivery routes change, layouts drift and scrapers rot quietly; whoever operates your pipeline inherits all of it, which is why access should be priced alongside the license itself.

The failure mode is concrete: the label appears in a listing, the delivered files tell a different story, and the gap surfaces mid-project when fixing it is most expensive.

You rarely have to take a vendor's word for it. 82.4% of the 1,744 datasets Datadory catalogs are free to access, and EOD Historical Data APIs - data_format lets you inspect the real artifact before any budget is committed.

Treat every claim of this attribute as testable:

1. Open EOD Historical Data APIs - data_format and compare its listing against the delivered artifact before paying for a commercial equivalent. 2. Open Tiingo Financial Data API - short_description and confirm its record — "REST and WebSocket API for end-of-day and real-time equity prices" — against the files you actually receive. 3. Open Massive - data_formats and confirm its record — "JSON, CSV, WebSocket stream, S3 flat files, SQL" — against the files you actually receive. 4. Pin down update cadence in writing.

Adjacent concepts worth reading next: - end-of-day prices - real-time market data - REST API - tick data - token-based API auth