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English
$
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I will develop custom web apps, apis, integrations and automations
Efren Alvarez
About this gig
I will develop custom web applications, backend systems, APIs, and third-party integrations tailored to your business needs.
I can help you build new features, create an MVP, integrate external services, automate workflows, or improve an existing application.
I work with technologies such as Node.js, NestJS, Next.js, PostgreSQL, REST APIs, authentication systems, payment integrations, WhatsApp APIs, CRM integrations, and business automation.
My services can include:
- Custom web application development
- Backend and REST API development
- Database design and integration
- Third-party API integrations
- Authentication and user management
- Dashboards and administrative systems
- Payment gateway integrations
- WhatsApp and CRM integrations
- Workflow and business process automation
- Bug fixing and improvements to existing applications
You will receive clean, maintainable source code and clear communication throughout the project.
Every project has different requirements, so please contact me before placing an order. I will review your needs and recommend the best package or create a custom offer based on the scope of your project.
Get to know Efren Alvarez
Efren Alvarez
Cybersecurity Engineer
- FromMexico
- Member sinceSep 2026
- Avg. response time1 hour
Languages
Spanish, English
I am a Cybersecurity Engineer who graduated in 2025, with more than five years of experience in software development and cybersecurity. Throughout my career, I have worked on developing secure and reliable software solutions for a wide range of clients, from small businesses to international companies.
My experience includes web and mobile application development, backend systems, automation, and the implementation of security practices throughout the software development process.
My Portfolio
FAQ
Do I need to contact you before placing an order?
Yes. Please contact me before ordering so I can review your requirements, project complexity, integrations, and expected functionality. This helps ensure you select the right package.
What technologies do you work with?
I mainly work with Node.js, NestJS, Next.js, PostgreSQL, REST APIs, third-party integrations, authentication systems, payment gateways, WhatsApp APIs, CRM integrations, and business automation.
Can you work on an existing project?
Yes. I can review existing codebases, add new features, fix bugs, create integrations, improve backend functionality, or extend an existing application.
Can you integrate third-party APIs?
Yes. I can integrate REST APIs and external services such as payment platforms, CRM systems, messaging services, authentication providers, and other business tools.
Can you build both frontend and backend?
Yes. Depending on the project, I can develop the frontend, backend, database, APIs, and integrations required for a complete web application.
Do you provide the source code?
Yes. Source code is included according to the selected package or custom offer.
Can you build an MVP for my business idea?
Yes. I can help transform your requirements into a functional MVP. Contact me first so we can define the features and scope before starting.
Can you deploy the application?
Yes. I can assist with deployment and configuration depending on your hosting provider and project requirements. Deployment can be included in a custom offer if needed.
What do I need to provide before we start?
Please provide a description of the project, required features, preferred technologies if applicable, API documentation or credentials for integrations, design references, and access to existing code if the project already exists.
