A backend for loan applications and business-for-sale listings

The challenge

Applying for a loan through an intermediary usually means paperwork handed over in person and no visibility afterwards. Buying or selling a small business is similar: listings are scattered, and nobody has checked them.

Trusted Connect set out to put both on one platform, with every application and listing reviewed by the firm’s own team.

The requirement

• A loan application an applicant can submit, amend while it is pending, and follow to a decision.
• Supporting documents attached to each application.
• Business listings for sellers and for buyers looking to acquire.
• An administrator who reviews everything before it moves forward.
• User profiles holding the identity and income details a lender needs.

The solution

Loans. Applicants apply for one of six loan types: personal, home, car, business, education or gold. Each application moves through defined stages from pending and under review to approved or rejected, then disbursed and closed. The system calculates the monthly instalment and the applicant’s debt-to-income ratio when an application is made. An applicant can edit or withdraw an application only while it is still pending.

Listings. Users post a business for sale, or a request to buy, with documents. Listings are categorised by business type and stay unpublished until approved.

Administration. Staff filter and review applications, record approved terms or a reason for rejection, and see summary statistics. For listings they approve, suspend, mark as sold or remove, and keep internal notes.

Architecture

The API is a NestJS application on PostgreSQL. It was started from our own NestJS foundation, which provides authentication, role checks, rate limiting, file uploads and API documentation from the first day, so the project’s time went into the lending and listing rules.

Sign-in uses Firebase Authentication with tokens verified on the server, and separate user and administrator roles. Documents are held in Firebase Storage. Status changes are restricted in the API according to who is acting and what state the record is in.

Technology

NestJS, TypeScript, PostgreSQL, TypeORM, Firebase Authentication and Firebase Storage.

Outcome

The backend for the first version was delivered: loan applications with their review workflow, moderated business listings, and user profiles.