Work on the services that power Loopt's website and mobile clients. Make new features possible. Integrate with custom services provided by Carriers, Data Providers (like Facebook and Yelp), and service providers (like SMS aggregators). Expose clean interfaces and hide complexity.

You must:

• Understand how computers, algorithms, memory, concurrency and data structures work. Be able to use and debug them.
• Be willing and able to learn new things every day.
• Have opinions. Be willing to voice and defend them.
• Be confident enough to ask questions and challenge false assumptions.
• Be creative! Be ready to face challenges that don't have obvious solutions.
• Have a degree in Computer Science or a related field.

We'd like you to have experience with:

• SQL We use MSSQL and a little PgSQL. You'll need to be able to write efficient queries and design schemata.
• C# Most of Loopt's server runs in the CLR. If you know Java you'll do fine.
• Security and encryption Know how to protect against impersonation, replay, and private data leakage. Understand how to store, transmit and protect sensitive information. Be able to identify, exploit, and eliminate edge cases and invalid assumptions.
• HTTP You should be familiar with everything from the protocol to SSL to tcp and sockets.

Bonus:

• ASP.NET experience. Understand the page lifecycle and how handlers, modules, viewstate and user controls work.
• Experience with Erlang, Java, and/or PHP.
• Experience with Windows and Linux native programming.

Demonstrate your experience: Show us what you've made! Wow us with demos and code samples :)
It's not strictly required you know Microsoft's stack in advance. Many current developers have learned it at Loopt.