RESTful API Development for Web App with Vector database and LLM for the AI Search

Create a restful api for apps backend. I dont know what the api lists need to develop. But here is the front end link to you analyze what api need to be created. The app have 3 roles (Brand, influencer, fans)
sq.citranagakencana.com

Dashboard
Brand : sq.citranagakencana.com/brand/dashboard
Influencer : still on develop, but here more less the features, bit like brand dashboard but have more features
Influencer Dashboard
- Influencer Dashboard
- Chat
- Calendar with project management with option to connect to calendar app
- Wallet (Deposit and withdraw) with transactions history
- Influencer details Profile edit/settings
- Fans Club Management (Membership, exclusive content, digital product, paid interaction, donation)
- Support ticket
- Notification settings (Notified by email, whatsapp or sms settings)
- Security (2FA and Change password, with login activity)
- Logout

The app have KYC verification : sq.citranagakencana.com/kyc-verification
Phone number verification

Vector database and LLM for AI Features like AI Search

Payment gateway will use xendit from indonesia to receive and send money

The API should include detailed documentation with endpoint descriptions, request/response examples, and error handling. Implement OAuth 2.0 authentication for secure access. The request and response payloads should be in JSON format. The responses will use standard JSON objects. The API documentation must include in-depth descriptions, detailed endpoint specifications, sample codes, error codes, and example responses. Incorporate advanced features like project management, transaction history, and security settings for each user role.

Prefer Node.js and Express for the API development.