Senior Backend Engineer (TypeScript & AI)

Scale Up Recruiting Partners; San Juan (PR); On-site; USD 120,000 - 170,000; Full time

Job summary

Scale Up Recruiting Partners is seeking a Senior Backend Engineer for a fast-growing AI startup. You will build backend services, data layers, and integrations that power our platform with a focus on scalability and reliability.

This role emphasizes AI-assisted development, modern tooling, and working closely with founders to implement AI-powered workflows in a lean startup environment.

Qualifications

• Strong experience building backend apps with TypeScript.
• Node.js experience in production systems.
• Experience with asynchronous queues and distributed processing.
• Designing scalable backend architectures and data models.
• Experience maintaining multiple third-party integrations.
• Ability to work with inconsistent external APIs and build resilient adapters.
• Strong debugging skills in production environments.
• English written and spoken communication.
• Ability to work independently with minimal supervision.

Responsibilities

• Design, build and maintain scalable backend services using TypeScript.
• Own and improve the platform's data layer and backend runtime.
• Design efficient database schemas and optimize performance.
• Build, maintain and improve integrations with third-party APIs.
• Create adapter layers that normalize external data.
• Debug asynchronous systems, queues and distributed workflows.
• Improve observability and platform reliability.
• Collaborate with founders to implement AI-powered workflows.
• Evaluate and adopt new AI development tools to boost productivity.

Skills

TypeScript backend

Node.js

Async job systems

Backend architectures

Third-party integrations

External API resilience

Debugging production

English communication

Independent working

Browser automation concepts

SQL databases

Tools

Claude Code

OpenAI Codex

Cursor

Job description

About Our Client

Our client is a fast-growing AI startup that has scaled from $0 to $1M ARR in just seven months and is entering an exciting stage of growth.

With a lean team of only 12 people, they're building AI-powered products and infrastructure that leverage the latest advancements in automation, intelligent agents, and modern software engineering. The company has already validated its product and is now focused on scaling its platform, improving reliability, and building the next generation of AI-driven systems.

This is an opportunity to work directly with highly technical founders, have a real impact on the product, and grow alongside a company with significant long-term potential.

About The Role

We're looking for a Senior Backend Engineer who enjoys solving complex engineering challenges and is excited about applying the latest AI tools to improve software development and operational efficiency.

This role focuses on building and maintaining the backend infrastructure that powers the company's platform, including the data layer, application runtime, asynchronous processing systems, and third-party integrations.

Beyond writing great code, we're looking for someone who embraces modern AI-assisted development, constantly explores new technologies, and enjoys building scalable, resilient systems in a fast-paced startup environment.

What You'll Do

• Design, build and maintain scalable backend services using TypeScript.
• Own and improve the platform's data layer and backend runtime.
• Design efficient database schemas and optimize application performance.
• Build, maintain and improve integrations with multiple third-party APIs.
• Create adapter layers that normalize inconsistent external data structures.
• Debug complex asynchronous systems, queues and distributed workflows.
• Improve observability, monitoring and overall platform reliability.
• Collaborate closely with the founders to implement AI-powered workflows and automation across the engineering organization.
• Continuously evaluate and adopt new AI development tools that improve engineering productivity.

Required Qualifications

• Strong professional experience building backend applications with TypeScript.
• Experience working with Node.js.
• Production experience with asynchronous job systems, queues, and distributed processing.
• Experience designing scalable backend architectures and data models.
• Comfortable working within large TypeScript codebases (300k+ LOC or comparable complexity).
• Experience building and maintaining multiple third-party integrations.
• Ability to work with inconsistent or undocumented external APIs and create resilient integration layers.
• Strong debugging skills across asynchronous systems and production environments.
• Understanding of concurrent browser automation and browser fingerprinting concepts.
• Familiarity with SQL databases.
• Hands-on experience using AI development tools such as Claude Code, OpenAI Codex, Cursor, or similar.
• Excellent written and spoken English.
• Ability to work independently with minimal supervision.

Nice to Have

• Experience building AI agents or agentic workflows.
• Python experience.
• Experience with React, Next.js or Svelte.
• Experience with ClickHouse or Convex.
• Experience working with email infrastructure or marketing technology.
• Startup experience.
• Product-minded engineering approach.

Who You Are

We're Looking For Someone Who

• Is naturally curious and constantly experimenting with the newest AI technologies.
• Loves solving difficult backend and infrastructure problems.
• Thrives in fast-paced startup environments.
• Takes ownership without waiting for direction.
• Communicates proactively and works well in remote teams.
• Enjoys shipping quickly while maintaining high engineering standards.
• Thinks beyond code and understands how engineering decisions impact the business.

Why Join?

• Join an AI startup at an exciting stage of growth.
• Work directly with technical founders.
• Build products using cutting-edge AI technologies.
• High ownership and real product impact from day one.
• Lean team with minimal bureaucracy.
• Flexible remote work.
• Opportunity for rapid professional growth as the company scales.