EatCheck gives three answers: yes, no, and check the label. The third one is the least satisfying, and we get asked about it a lot. So here is exactly when and why we refuse to give a clean verdict.
Some ingredients have two possible origins
The classic is "natural flavouring". It can be made from plants. It can also be made from animal sources. The label does not say which, and the manufacturer is not required to tell you.
A real example from our database: a gluten-free chocolate chip cookie whose ingredient list is maize starch, palm oil, chocolate chips with sunflower lecithin, sugar, and so on. Every named ingredient is plant-based. But "natural flavouring" appears twice, so Open Food Facts marks the product "maybe vegan", and we pass that doubt on to you instead of hiding it.
Other regulars in this group: mono- and diglycerides (E471), which can come from soy or from animal fat, and gelatin, which is animal-derived but sometimes appears in lists without a stated source.
Traces are a judgment call, so we show them
795 products in our database carry a "may contain milk" style warning that matters for a vegan check. Whether that is a dealbreaker depends on why you avoid the ingredient. For a milk allergy, traces are serious. For ethical veganism, many people accept them. We are not going to make that call for you, so we surface the warning and leave the decision where it belongs.
Sometimes the data is just not there
When a product has no usable ingredient list, or the list is in a language our scan does not fully cover, we say that plainly. An answer built on missing data is not an answer.
The halal numbers show why this honesty matters
Of our 28,601 products, 13,481 check out as halal and 2,045 clearly do not (pork appears on 677 labels, wine on 380, alcohol on 248). That leaves 13,075 products, almost half, in the gray zone that Islamic scholarship calls Mushbooh: doubtful. Mostly it comes down to the same ambiguous additives, E471 and gelatin above all.
Any tool that turns that gray zone into confident green checkmarks is making things up. We would rather tell you the truth: read the label, look for certification, and when in doubt, ask the manufacturer.