How do you motivate co-founders to commit with you on an idea?

You need to make it real. Have the hard conversations. 'Are you in or out?' If you are in, here is what you get. Then you talk about real salary, or real ownership. Make it contingent on milestones and progress. If those are not hit, then the attached condition is forfeit. If they are out, thank them for the time, then go find someone who is in.

Running teams is hard. Remote teams is hard. Side projects even harder. Unpaid side project even harder still... Not knowing roles I would say to Include them in conversations with the other cofounder who is contributing and make them feel engaged. Ask specific questions that relate to their piece (if design, do you think this cta I mocked up works? What would you do differently? I think it should be fun/serious/a pun/etc what do you think?) in as limited a scope as possible so they don’t feel overwhelmed and can spend 20min to play with something and toss it back to you and succeed. If they don’t commit to the success quickly after a few weeks of this then you must fire them, and you and the person who are working on it fill in and do their job as best you can. Perfection is the enemy of the great and the death of the good. Learn to do all the things yourself :) keep working!

My personal experience with trying to bring people into my side project has been that 95% of people are just talkers.  Most people in this industry, especially programmers have grand ambitions, and this has to do with the fact that we're constantly bombarded with the news of some 20 year old with a billion dollar exit which is beyond rare.  When most realize that they have to spend time after work and on weekends, month after month with very little probability of success, they just give up. I've seen it way too many times to count.  I made a mistake of bringing someone on board who just wasted my time, copied part of my idea and tried to do it himself, needless to say he failed in his endeavor.  Just be careful who you bring aboard, people are not what they seem when they have to roll up their sleeves and get their hands dirty.

We also have a team living in different cities (we are 6 people) and in order to stay motivated and productive, we communicate and arrange online teambuilding such as discussing books and films on the topic of our work, discussing news and hosting online parties or games.

I totally agree with @Duane Wilson. The key here is detailed discussion. And even though it's a side project for everyone, the relationship and roles must be formalised. If you don't have a co-founders agreement with detailed description who's responsible for what, it makes sense to draw at least a memo for everyone to be reminded what their areas of responsibilities are. I've actually found it useful in any teams - formal, or informal. Besides, you might want to use something from agile practices, - like weekly meetings (virtual, naturally) with setting up goals and expectations. Then make everyone touch base daily and discuss, what have they done so far, what they are going to achieve today and if there's anything that blocks the way to success. For daily "meetups" there's even no need to use Zoom, - a few sentences in Slack channel will do. As I see it, if 50% of the team members deliver and 50% don't - it might be not a question of motivation, but rather a project management issues. Make interaction and reporting more transparent and regular, and you might find that the work is done faster than you'd hoped:) good luck

I'd recommend using Good Time Journals from the book Designing Your Life to zoom in on activities your cofounder enjoys and work to consciously integrate those into their every day! Here's a link to the sheets, which have you note down activities you find engaging and activities that give you energy (the two can be subtly different): https://designingyour.life/wp-co...

As other have said you (and your co-founder) need to have a discussion with those people. You anyway can't go through life and building a company without having difficult conversation, so why not practice now? I'm currently in a team of 2, but our time commitment is different. We had several discussions about time commitment, financial commitment, how we work as individuals (Manual of Me) and as a team (team charter). This is all document. If this is a side project for everyone I'd not suggest daily meetups, even if it is just asynchronous. It increases the pressure. I'd rather discuss how do team members schedule time for this project (a couple of hours every day, several large blocks of time on 2 days etc) and ask them to commit to this schedule and post an update afterwards.

1. Prove that you have a Must-Have product that solves a real macro problem. e.g. can you get 10,000 people to like it on social media or sign up on a 1pager homepage? 2. Share with the others why you plan to contribute all of your time, energy, and interest into solving this problem. 3. Ask the following while with your team: ---> [Gauge interest] Will you (or your founders) be sick of it long before it's done? ---> [Gauge contribution level] Do you actively contribute to the industry that you're aiming to disrupt? If not, you're at risk of reinventing the wheel. ---> [Gauge importance] Is solving this problem truly important? Are you willing to put money into it? 4. If you don't have all three in #3, move on :)

co-founders often are investing with time or money. for their investment they should expect to receive equity in the company. especially if they are committing time, it is important to properly incentivize them with this equity because otherwise they are working for free. If you're concerned with their performance moving forward, their equity can vest over time and you can evaluate their performance at certain milestones you've set for the company. for example they receive 5% of the company now for signing on, and 2.5% each year for up to 4 years. this way they get part of the company now and can work to get more, which can help keep interests aligned. the amount and timetable is up to you. this is assuming you haven't already signed over nor promised equity. from my experience, if people are not pulling their weight you need to speak with them and listen. give people a shot and more often than not they will impress you. if they aren't delivering work because they don't believe in the company then it would time to part ways.