I know this is probably just made in good fun, but as a consultant who frequently works with startups[1], I recommend not doing something like this. If you hav

I know this is probably just made in good fun, but as a consultant who frequently works with startups[1], I recommend not doing something like this. If you have delivered the final product to the client and they are not paying your invoice, your first step should be to try and cordially resolve the situation with a frank discussion about your expectations and mutual commitments, and nudged with references to the signed statement of work. In my experience there are three types of clients. Clients who pay, clients who can't pay, and clients who won't pay. My recourse, and what I recommend to others, is as follows: 1. For new clients, require a 1/3 deposit before you begin the work, payable towards the final invoice. If the client cannot pay the first invoice, you know they will struggle to pay all of them and you haven't wasted your time. 2. Depending on how long the engagement is expected to run, require payments towards the final invoice every n weeks. This limits your exposure in case the client suddenly cannot or will not pay. 3. Ensure that your statements of work and other contracts are reviewed by a competent lawyer (as 'patio11 and 'tptacek would say, pretty much any lawyer as long as they are competent). This limits your liability and exposure in case you need to sue. 4. If there is a disagreement over terms after both parties have signed, or the client cannot pay, be charitable and attempt to resolve it in ways that are not antagonistic. Try to work out payment plans, or change the scope such that it is still affordable for the client. Accept that for certain situations, you will not recoup invoices (e.g. the client literally has no money for you). Steps 1 and 2 are designed to limit the impact for this latter case. 5. If the client will not pay, start with civil discussion first, then escalate by involving lawyers and strongly worded letters. Specifically, do not do anything passive aggressive. I would recommend revoking their license to use the software before you alter their public deployment and potentially cause them brand, reputational or business continuity damage. 6. Establish a high quality pipeline of qualified leads, especially from referrals, who you can consider more trustworthy with invoice payment. In my experience, I have never had a referral default on an invoice. Now, the vast majority of my business comes through referrals (there are many other benefits to a referral pipeline as well). [1]: Read - clients who are statistically likely to default on their outstanding invoices. EDIT: Typo...pipeline of leads from referrals, not lawyers :)