Making online resources and websites for kids is hard, especially since laws and guidance are in place to ensure they are safe online. These laws are there for good reasons and are great to keep our kids safe when surfing the web, but can be a real pain to developers, just trying to make helpful resources for kids.
You should make a privacy policy to explain to children using your service how you collect their data and why.
Please note: I have only researched the requirements in the UK, however the basic principles still apply to most countries' guidance.
I am not legal advice and you should always research specific requirements for your country and consult a lawyer when unsure.
If under the age of 13, you should ensure the child using the site has got the 'consent'/permission for their parent/guardian, unless your site provides a 'preventive or counselling service'.
You should write a policy, specifically for children. This means that in your case most automatically generated priavcy policies are garbage. It needs to be 'clear [...] so that they are able to understand what will happen to their personal data, and what rights they have.'
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