Open WebUI uses a modified BSD 3-Clause license. You can modify it for your business needs — redistribution with modification is explicitly permitted.
However, there's a key restriction (Clause 4-5): you cannot remove or alter "Open WebUI" branding unless you fall into one of these exceptions:
You have 50 or fewer end users within any rolling 30-day period You're a contributor with a merged PR and have written permission You have an enterprise license So for small-scale use (<50 users), you're fully fine. For larger commercial deployments, you'd need to either keep the branding or obtain an enterprise license from Open WebUI Inc.