Senior Full Stack Engineer (Independent Contractor)

Location | Latin America — Remote

Engagement Type | Independent contractor (services agreement)

Availability | General overlap with U.S. Eastern Time

About LoanBud

LoanBud is a financial technology platform focused on SBA and small business financing. We help entrepreneurs secure capital to grow, start, acquire, or refinance a business through a process that is faster, clearer, and easier to navigate.Our platform connects business owners, buyers, brokers, sellers, referral partners, and lenders, and combines technology with experienced lending professionals to support borrower intake, document collection, prequalification, lender matching, underwriting, communications, and moving a loan from application through closing.

Engagement Overview

LoanBud is seeking an independent contractor to provide senior full stack engineering services, helping build, maintain, and improve our proprietary lending and workflow platform — used by borrowers, loan officers, processors, underwriters, referral partners, lenders, and internal teams.This is a hands-on engagement with a strong backend focus, delivered primarily in our Java and Spring Boot environment while also contributing to TypeScript front-end work, integrations, database development, background processing, and cloud infrastructure. We're looking for a provider comfortable working inside an existing production application — someone who can understand the current architecture, improve it thoughtfully, resolve bottlenecks, and deliver reliable functionality, rather than rebuild from the ground up. The engagement calls for strong technical judgment, clear communication, and the ability to own a deliverable from requirements through production deployment.

Core Technology Stack

Application: Java 21, Spring Boot 3.3.x, PostgreSQL 15+, Spring Data JPA, Liquibase, MapStruct, OpenAPI Generator, Spring Security, JWT, Caffeine, OpenFeign, Lombok.Background processing & workflow: JobRunR, Drools, AWS S3, Playwright, Twilio, Thymeleaf.Broader platform: TypeScript, PHP, AWS, Terraform.

Scope of Services The contractor will provide services across the platform, which may include:

Backend — build and maintain backend services, APIs, business logic, security controls and integrations in Java 21 / Spring Boot; implement underwriting and business rules in Drools.

Front end — build and improve TypeScript front-end functionality.





Data — design and maintain PostgreSQL models, queries, relationships and migrations (Spring Data JPA, Liquibase).

Integrations — connect internal and external services via REST APIs, webhooks and OpenFeign; maintain OpenAPI specs.

Async & workflow — build and support background jobs, scheduled processes, retries and monitoring (JobRunR).

Platform features — document storage (S3), email/PDF/document generation (Thymeleaf, Playwright), SMS (Twilio), and caching/performance (Caffeine); contribute to PHP backend and AWS/Terraform infrastructure as needed.

Reliability — diagnose and resolve production bugs, failed jobs, performance, security and integration issues; improve monitoring, logging, error handling, speed, reliability and security.

Delivery — produce clean, tested, documented code; support review, release management and production deployment; evaluate tradeoffs across speed, scalability, maintainability, cost and business impact; and communicate clearly on progress, risks and blockers.

Product Areas

Loan applications and borrower intake; borrower and referral-partner portals; CRM and contact management; document collection and review; prequalification and eligibility; financial spreading and loan calculations; underwriting workflows; loan conditions and approval tracking; lender matching and collaboration; internal task and workflow management; communications (email, SMS, voice); PDF and document generation; reporting and analytics; permissions and role-based access; third-party lending and financial-data integrations; and AI/workflow automation.

Required Experience

· 5+ years of professional software engineering experience.

· Strong Java and Spring Boot experience; production APIs and backend services.

· Strong PostgreSQL / relational databases; Spring Data JPA or comparable ORM.

· TypeScript front-end experience.

· REST APIs and webhooks; authentication, authorization, JWT and role-based permissions.

· Background jobs, scheduled processes, queues or async workflows.





· Deploying and supporting applications on AWS or comparable cloud; Git, automated testing, CI/CD, monitoring and production deployment.

· Ability to troubleshoot across front end, backend, database, infrastructure and integrations.

· Secure development practices for sensitive customer and financial data.

· Strong written and spoken English; strong accountability and attention to detail; able to work autonomously while maintaining visibility.

· Willingness to improve an existing platform rather than unnecessarily replace working systems.

Nice to Have

Java 21 / Spring Boot 3

- Liquibase, MapStruct, OpenAPI Generator, OpenFeign, Caffeine or Lombok
- JobRunR or another job framework
- Drools or another rules engine
- Thymeleaf, Playwright or HTML-to-PDF
- Twilio
- AWS S3
- Terraform
- PHP; fintech/lending/regulated-industry experience; loan origination, CRM, borrower portal, underwriting or document-management systems
- OCR, document classification, financial spreading or data extraction
- AI/LLM in production; multi-tenant apps and complex permissions; distributed teams; early/growth-stage companies.

Selection Process

Interested providers should submit a résumé or profile, a brief note on their interest, a description of their Java/Spring Boot/PostgreSQL/TypeScript/AWS experience, examples of production applications they built or materially contributed to (with their role), links to GitHub or work samples where available, and their general U.S. Eastern Time availability.

Selected providers will have an initial conversation; a technical discussion covering Java, Spring Boot, APIs, databases, security and architecture; a practical evaluation on a realistic engineering problem (problem-solving, code quality, architecture, maintainability, security); and a final conversation on scope, ownership and commercial terms.

Be Part of Our Growth Story

LoanBud is building a better way for entrepreneurs to access capital, and technology is central to that effort. This engagement is a chance to help shape a core financial technology platform, solve real operating problems, and build tools that help borrowers move faster, help partners close more transactions, and give lenders a clearer path to funding.

We're looking for a provider who takes ownership, communicates directly, and follows through. Our mission is to empower entrepreneurs to gain access to capital.

📌 Full Stack Engineer (México)
🏢 LoanBud
📍 México