Don Kavi Agency is growing, and we're looking for a Senior Full-Stack Engineer to join our team and help build secure, high-performing custom web applications for U.S.-based clients.

This role is adecuado for an experienced engineer who is comfortable owning complex technical projects from front-end development through backend architecture, database design, cloud infrastructure, and secure payment integrations.

You'll work closely with our developers, designers, Account Managers, and other digital specialists to build meaningful digital products and solve complex business challenges.

What You'll Be DoingYou'll help design, build, and maintain custom web applications with a strong focus on security, reliability, and payment functionality.

- Some of what you'll do includes:Build and maintain production web applications using React, Next.js, Node.js, and Express.
- Design and maintain PostgreSQL databases, including schema design, queries, and migrations.
- Develop secure integrations with payment processors such as Stripe and PayPal.
- Implement payment functionality, including tokenization, webhook verification, idempotent charges, refunds, disputes, and reconciliation.
- Deploy, maintain, and optimize applications and infrastructure in AWS.
- Design and implement secure authentication, session management, and role-based access control.
- Build systems that safely handle sensitive personal and financial data.
- Implement audit logging, secrets management, least-privilege access, and other secure development practices.
- Identify, troubleshoot, and resolve complex technical and security-related issues.




- Maintain high standards for code quality, performance, scalability, and reliability.
- Collaborate with cross-functional teams to translate business and client requirements into technical solutions.
- Contribute to technical architecture, development processes, and engineering best practices.

What We're Looking ForWe're looking for a senior engineer who is thoughtful, reliable, security-conscious, and comfortable taking ownership of complex technical work.

You should have

✔ 5+ years of experience building and shipping production web applications.

✔ Strong experience with React and Next.js.

✔ Strong backend development experience with Node.js and Express.

✔ Strong experience with PostgreSQL, including schema design, complex queries, and database migrations.

✔ Production experience working with AWS.

✔ Experience integrating payment processors such as Stripe and/or PayPal.

✔ Experience working with payment concepts such as tokenization, webhook verification, idempotent transactions, refunds, disputes, and reconciliation.

✔ Working knowledge of PCI DSS scope and secure card data handling.

✔ Strong understanding of secure development practices, including the OWASP Top 10, authentication and session design,



role-based access control, audit logging, secrets management, least-privilege access, and dependency hygiene.

✔ Experience handling sensitive personal data in production environments.

✔ Professional English communication skills.

✔ Availability to collaborate with the team during overlapping hours with U.S. Central Time.

Experience with any of the following is a plus:

Regulated or compliance-driven products.

- Salesforce API integrations.
- QuickBooks API integrations.
- WordPress, Shopify, or other CMS and e-commerce platforms.
- Complex interactive user interfaces, including drag-and-drop functionality and multi-step wizards.
- PDF and Excel report generation.
- What It's Like to Work With UsFully remote team.
- Opportunity to work on complex and meaningful projects for U.S.-based clients.
- Collaborative environment with developers, designers, marketers, and Account Managers.
- Exposure to a variety of industries, technologies, and digital products.
- A team that values ownership, clear communication, accountability, continuous learning, and thoughtful problem-solving.
- Opportunity to contribute beyond writing code and have a meaningful impact on how projects are designed and built.

We're looking for someone interested in building high-quality solutions and growing with a collaborative team over the long term.

If this sounds like the type of work you enjoy, we'd love to hear from you. Please apply with your resume and any relevant portfolio, GitHub, or examples of projects you've worked on.

📌 Senior Full-Stack Engineer- Payments & Security (Colombia)
🏢 Don Kavi Agency
📍 Colombia