monday.com's API is GraphQL at https://api.monday.com/v2. The token goes in Authorization with no prefix.
Copy your personal token from Avatar → Developers → My access tokens in monday.com. In the examples it's written {{MONDAY_TOKEN}}.
Full reference: https://developer.monday.com/api-reference/docs
curl -X POST https://api.monday.com/v2 \
-H "Authorization: {{MONDAY_TOKEN}}" \
-H "Content-Type: application/json" \
-d '{"query": "{ me { name email } }"}'curl -X POST https://api.monday.com/v2 \
-H "Authorization: {{MONDAY_TOKEN}}" \
-H "Content-Type: application/json" \
-d '{"query": "{ boards(limit: 5) { id name items_page(limit: 5) { items { id name } } } }"}'