abettor is an R package for connecting to the online betting exchange Betfair, via their API-NG product, using JSON-RPC. The package can be used to retrieve market information, place bets, cancel bets and manage account information such as balance, statement and P&L. The breadth of API calls covered is growing, although not yet complete. If your use case is not yet covered, raise an issue or write new functionality yourself. New contributors always welcome.