There are provided systems and methods for a dongle device for automatic pairing of payment terminal to mobile computing device. A merchant location may include one or more merchant devices used to provide sales to between the merchant and customers through generating transactions and processing payments. In this regard, the merchant devices may use connectable terminals that provide payment instrument processing. The connectable terminals may utilize a wireless connection with a merchant device and allow a user to provide their payment instrument, such as an EMV payment card, to the terminal to insert their payment information into a transaction. In order to pair the terminal to the merchant device, a dongle device may be added to the terminal to provide connection information to the merchant device for automatic pairing. The dongle device may also remove the connection information on removal or insertion of a new dongle device.