Microscale fiber tip sensors based on the plasmon resonance are reported. The fabrication process derived from our previous approach for manufacturing near-field scanning optical microscopy probes has been optimized for sensing applications. A typical tip sensor is a tapered fiber $400\mathrm{\mu }\mathrm{m}$ in length, coated with a nanoporous thin silver film. The miniaturized geometry of the sensor allows detection in a single droplet of liquid solution $(\sim 20\mathrm{\mu }\mathrm{l})$ . The tip sensor is sensitive for refractive indices between 1.33 and 1.40 with a sensitivity of at least $3\times {10}^{-4}\text{refractive index unit (RIU)}∕\mathrm{nm}$ . The Raman scattering enhancement through these microsensors demonstrates the important role played by the localized plasmon resonance. The sensors' linear response covers a large region, interesting for biosensing in aqueous environments such as biomedical applications.