A dozen event tech startups crashed and burned because they tried to solve everything for everyone at once. The messy operational side - budgets, vendor tracking, quotes, invoices - is a real pain. But here's the thing: event planners and vendors have completely different workflows. Pick one segment first, or your feedback will be all over the place and impossible to act on.
Someone recently asked me for honest feedback on their tool. Advised them not to demo on the call - watch them walk through their current workflow with screen share instead. The gaps reveal themselves. You'll learn more in thirty minutes than weeks of survey responses.
Also worth asking what they last paid for that didn't solve this. Tells you willingness to pay fast.
For finding real testers, niche Facebook groups or LinkedIn groups for event planners convert way better than open forums. Those people are actively venting about the exact problems you solve.
If you're building this, focus on what you'd actually need to replace - not just be a nice addition. Spreadsheets and email are the real enemies. Give me something that replaces both, and I'll pay.