OSRM - Utilities, Application Utilities, and Mapping APIs
ArcGIS - ArcGIS software is a data analysis, cloud-based mapping platform that allows users to customize maps and see real-time data ranging from logistics support to overall mapping analysis.
pgRouting - Repository contains pgRouting library. Development branch is "develop", stable branch is "master" - pgRouting/pgrouting
Google Maps - Find local businesses, view maps and get driving directions in Google Maps.
Mapbox - An open source mapping platform for custom designed maps. Our APIs and SDKs are the building blocks to integrate location into any mobile or web app.
OpenRouteService.org - The spatial services API with plenty of features.