Preliminary evidence indicates potential benefit of providing caregiver-mediated intervention, prior to diagnosis, for infants at elevated familial likelihood for autism and related developmental delays including language delay (EL-A). However, delivering such interventions online and in low-resource settings like India has not been reported. This study aimed to evaluate the feasibility and acceptability of delivering a novel manualized caregiver-mediated early support program, the "LiL' STEPS," online in India, for EL-A infants. LiL' STEPS stands for Language development & Intervention Lab's (LiL') Supporting Early social-communication and language by Promoting caregiver Sensitive responsiveness (STEPS). The program comprised 14 sessions with a focus on social-communication and language, conducted over 12-weeks using demonstration and video feedback. Families of 36 EL-A infants aged 9 to 15-months participated in this feasibility randomized controlled trial (RCT). Families were randomized in a 2:1 ratio (n = 24 LiL' STEPS and n = 12 care as usual groups). Information on feasibility and acceptability was collated following a mixed methods approach from caregiver interviews, fidelity forms, session notes, and study register. Findings indicated the LiL' STEPS study trial as feasible and acceptable with recruitment rate of 4 per month, 100% willingness for randomization, 8.3% attrition, and 3.03% loss of blinding. Interventionist and caregiver fidelity was maintained above 80%. Despite challenges like interruptions during sessions, 100% families found the program acceptable and satisfactory, 86% said they would recommend the program to others, and 71% preferred online modality. Caregivers' perspectives on beneficial components and experience attending the program have been described. Accordingly, recommendations for future definitive RCTs have been presented.