fyndlr was developed from the ground up using the Tornado Web Server for Python. The web app and web service are powered by Tornado.
We rely on AWS to run our service. The servers are EC2 instances utilizing EBS and auto-scaling. Everything sits behind an Elastic Load Balancer. Images for lost or found items are stored on S3. Route53 hosts are DNS records. Messages to users are sent via the Simple Email Service. To top it all off, we use CloudFormation templates to re-deploy the entire service instantly!
The backend service that powers fyndlr implements MongoDB. All data about lost & found posts and users are organized in MongoDB collections. We rely heavily on MongoDB for our geolocation functionality. Since our service was written in Python, we implemented PyMongo to interface with our MongoDB instance.