Experience sampling or ecological momentary assessment offers unique insights into how people think, feel, and behave in their natural environments. Because the method is able to capture situational variation as it happens in "real time," experience sampling has become an increasingly popular method in social and personality, psychology, and beyond. With the ubiquity of smartphone ownership and the recent technical advances, conducting experience sampling studies on participants’ own devices has become increasingly easy to do. Here, we present one reliable, user-friendly, highly customizable, and cost-effective solution. The web-based application, SurveySignal, integrates the idea of using short message service (SMS) messages as signals and reminders, according to fixed or random schedules and of linking these signals to mobile surveys designed with common online survey software. We describe the method and customizable parameters and then present evaluation results from nine social–psychological studies conducted with SurveySignal (overall N = 1,852). Mean response rates averaged 77% and the median response delay to signals was 8 min. An experimental manipulation of the reminder signal in one study showed that installing a reminder SMS led to a 10% increase in response rates. Next to advantages and limitations of the SMS approach, we discuss how ecologically valid research methods such as smartphone experience sampling can enrich psychological research.