Dendritic cells (DCs) are sentinel cells that orchestrate immune responses to infections, cancer, and tissue damage. DCs play a crucial role bridging the innate and adaptive immune systems and elicit tailored adaptive immune responses. Manipulation of DCs is critical for immune interventions such as vaccination, and DC-based immunotherapies and showed promising results as anti-cancer therapeutics, treatment of infectious diseases or autoimmune disorders. Calcium, a ubiquitous secondary messenger, regulates many critical effector functions of DCs like phagocytosis, maturation, migration, and cytokine production. However, regulation and mobilization of calcium in DCs remains poorly understood mainly due to a lack of tools. To decipher calcium signals induced by bacterial stimuli in DCs, we generated different mouse models allowing the expression of the genetically encoded calcium indicator, GCaMP6f specifically in dendritic cells to allow the visualization and analysis of calcium dynamics within DC, in vitro but also during intravital imaging. Using intravital microscopy on mice intravenously injected with bacteria, we reveal that oscillatory nature of the calcium signal within splenic DCs and show that the pattern of the calcium signals was specific to the type and viability of the encountered bacteria. These calcium dynamics elicited by live bacteria correlate with reactive oxygen species production, the production of key cytokines and bacterial killing. This study underscores the crucial role of calcium homeostasis in DC biology, and pave the way for innovative strategies for DC-based interventions.