This disclosure relates to using trust tokens to verify the integrity of devices and applications from which data is received. In one aspects, a method includes receiving, from a client device, a request for one or more trust tokens. The request includes at least one of one or more device-level fraud detection signals obtained from the client device or data representing code of an application that initiated the request. The request also includes a respective nonce for each of the one or more trust tokens. A determination is made, based on at least one of the one or more device-level fraud signals or the data representing the code of the application, to issue the one or more trust tokens to the client device. Each trust token is generated using the nonce for the trust token. The one or more trust tokens are provided to the client device.