Before you jump into negotiating, take a step back and figure out what you actually need to stay in business. A 20% cut sounds catastrophic when you hear it cold, but the real question is whether losing this client entirely would hurt worse. If they're a significant chunk of your revenue and you can't replace them quickly, that changes the conversation. If they're one of several steady projects, you have more room to push back or walk away.
When you talk to them, don't lead with "I can't afford that." Instead, ask what triggered the request - are they restructuring their whole vendor costs, facing a specific budget crisis this quarter, or just testing to see if you'll negotiate? Their answer matters. Sometimes clients ask for cuts as a routine thing, not because they're actually desperate. Once you know what's real, you can explore middle ground that doesn't wreck your finances. Maybe they only need a discount on certain project types, or you could batch their work differently to lower your actual delivery cost. You might also tie a reduced rate to a longer contract commitment, so you know the revenue is locked in. The key is making it about solving their problem, not just absorbing their problem as your own loss.
One thing worth considering: if you do agree to anything lower, make it explicitly temporary or conditional. "We can do 15% off through Q1 if you commit to three projects" is different from resetting your baseline rate downward forever. Clients often interpret a one-time discount as the new normal, and then you're stuck. Be clear about what you're agreeing to and why.