What to do with code once startup has failed?

Choose a good license and open source it on GitHub or somewhere else. If your company failed that doesn't mean somebody else can find your product interesting and use it. There's a possibility that your product can be improved and, who knows, eventually released again for commercial use (if the license permits it).

1. Try to sell it on flippa.

2. Failing that, put it on github, with a note that says "unsupported". (open source) It can help for future job interviews.

3. Delete from your local machine and move on with your life.

I had a similar situation, with a functioning website with no revenue, and sold it on flippa.com. Didn't come close to recovering my investment, but it was in 4-figures.

Github?