The US is projected to run out of landfill space in less than twenty years. Fortunately, this is a preventable problem. Over 50% of garbage we send to landfills can be recycled, and about 25% can be composted. This problem of placing recyclable and compostable waste in the landfill can be solved either by a larger policy change that may take years for approval or more simply, by giving the public simple tools to figure out what bin to dispose their trash in.

After moving from Virginia to Seattle, our family encountered the challenge of learning the correct classification of trash into garbage, recycling, and compost. At the time, we primarily searched Google and used the small flier we had King County to figure out what bin to place waste in. This was time-consuming and unreliable.

That is where "What Bin?" comes in. It's a hands free means of figuring out which bin to put your trash in. As an Alexa Skill for Alexa-enabled devices, it finds an easy-to-access position in living rooms and kitchen counters all over the world.

What it does

User: Alexa, ask What Bin where to put Pet Food.
Alexa: Food and yard waste. Pet food goes in food and yard waste. 
Alexa: Your street now has 129 points and is #1 on the leaderboard.

“What Bin” is an Alexa skill that lets people to determine which bin their trash should go in – recycle, food and yard, recycle. If the item falls into none of these categories, it will provide a location where the item can be safely recycled/disposed.

All you have to do is ask an Alexa-enabled device, “Alexa, ask what should I do with [thing you want to trash]”. The skill will then respond with an answer and any other important information, such as whether the item should be cleaned before disposing.


  • Support for over 60,000 possible commands to find the bin for an item
  • Search for recycling locations for items that don't go in any bin
  • Slight gamification with a points-based system
  • Online leaderboards for friendly competition between streets

How we built it

We built the front-end with Amazon's Alexa Developer Console and the back-end in Python 3 and Amazon's Alexa Skills Kit. The back-end runs on an AWS Lambda function. This kind of serverless architecture is environmentally friendly because the servers our Lambda function run on stay off when nobody's using the Alexa Skill.

The back-end of the Alexa Skill uses various techniques to parse user input and search for a broader category for the input item. This data is then used to determine what to push to an online leaderboard on a remote server.

What's next for What Bin

We are in the process of publishing this Alexa Skill into the Amazon Alexa Skill library. We also plan on contacting the King County Recycling & Environmental Services team (we have met them in the past to discuss other recycling-related projects) to feature this on their website and drive awareness and promotion of this unique resource that will help our county’s waste management.

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