Watchlist API

Watchlists are user-customisable lists of financial instruments. The Watchlist API provides an interface to watchlists that are managed, and persisted between user sessions, by Transformer’s Watchlist Service.

A watchlist created with the Watchlist API is shareable in real time between a user’s devices. This is achieved by hosting the configuration of the watchlist (the list of instruments within the watchlist) as a persistent container on Transformer. This enables changes to the list to be shared between supporting StreamLink clients as fast as a price update would be.


The Watchlist API provides methods for creating, renaming and deleting watchlists, and methods for changing the financial instruments monitored by each watchlist.

The API is included with Caplin Trader 4.0.3, and requires at least Transformer 6.2.3 running the Watchlist Service 6.2.2.


Real time synchronisation between devices

Watchlist configurations are hosted centrally in Transformer as private containers. Changes to a watchlist’s configuration are automatically pushed to concurrent user-sessions on other devices.

Integrates with Caplin Trader’s Grid component

The Watchlist API includes an implementation of the GridDataProvider interface, which takes the hard work out of creating a dynamic link between a grid and a Transformer-hosted watchlist

Application neutral

Any Streamlink application that supports Transformer-hosted watchlists can make use of the watchlists created using Caplin Trader’s Watchlist API.

Ease of migration

Caplin Trader GUI components that use the Watchlist API can exist alongside components that use watchlists persisted by Webcentric.