Backend Engineer + Ai
We are looking for a Senior Backend Engineer with strong experience designing, building, and evolving scalable, reliable, and secure backend systems. This is a hands-on engineering role for someone who goes beyond feature implementation. We are looking for an engineer with strong technical judgment who can understand complex systems end-to-end, contribute to architectural decisions, identify and address technical debt, and continuously improve the quality and maintainability of our platform.
AI is becoming a core part of how we build software. We expect engineers to effectively use modern AI-assisted development tools while maintaining strong ownership and engineering judgment over the code and systems they deliver.
Responsibilities
Design, build, and evolve scalable backend services and APIs, primarily using Node.js, TypeScript, and Express.js.
Own technical solutions end-to-end, from design and implementation through deployment, observability, and production support.
Contribute to the evolution of our backend architecture and participate actively in architectural and technical design decisions.
Identify, prioritize, and address technical debt, balancing long-term maintainability with product delivery.
Apply solid software design principles and patterns, choosing appropriate solutions based on context and trade-offs rather than applying patterns by default.
Design clear application boundaries and separation of concerns across services, business logic, and persistence layers.
Design and optimize PostgreSQL schemas, queries, indexes, migrations, and transactional workflows.
Build reliable financial workflows with appropriate strategies for idempotency, concurrency, consistency, retries, failure handling, and reconciliation.
Design and maintain REST APIs and integrations with internal systems and external providers.
Design asynchronous and event-driven workflows when appropriate.
Build systems with strong principles around reliability, scalability, resilience, security, and performance.
Work with AWS infrastructure and cloud services as part of developing and operating production systems.
Improve production visibility through structured logging, metrics, tracing, monitoring, and alerting.
Investigate complex production incidents, perform root-cause analysis, and implement sustainable solutions rather than temporary fixes.
Maintain high engineering quality through automated testing, code reviews, documentation, and continuous refactoring.
Use AI-assisted engineering tools to improve development speed, testing, debugging, code review, and engineering productivity while maintaining human ownership of technical decisions.
Challenge existing technical decisions constructively and help continuously improve our engineering standards.
Share knowledge and contribute to strengthening the technical capabilities of the engineering team.
Collaborate closely with Product, QA, Data, Platform, and other engineers to translate business requirements into robust technical solutions.
Requirements
8+ years of professional backend engineering experience, with significant experience building and operating production systems.
Strong hands-on experience with Node.js and TypeScript in production environments.
Experience with Express.js or comparable backend frameworks.
Experience with Python and familiarity with backend frameworks such as FastAPI, Django, or similar is highly valued.
Strong knowledge of software architecture, design principles, and design patterns, including their trade-offs and appropriate use cases.
Strong understanding of relational databases and PostgreSQL, including data modeling, transactions, indexing, query optimization, migrations, and performance.
Experience working with ORMs and persistence patterns, understanding both their benefits and limitations.
Strong understanding of API design, authentication, authorization, versioning, security, and third-party integrations.
Experience designing systems for failure scenarios, including retries, duplicate events, partial failures, race conditions, and external-service degradation.
Solid understanding of distributed systems and asynchronous processing.
Experience with automated testing at different levels, including unit, integration, and end-to-end testing.
Production experience with AWS or comparable cloud infrastructure.
Experience with CI/CD, containers, and modern software delivery practices.
Strong understanding of observability and production troubleshooting.
Ability to analyze architectural alternatives, identify trade-offs, and clearly explain technical decisions.
Strong ownership, problem-solving, and communication skills.
Ability to work autonomously on complex technical problems while collaborating effectively with the broader team.
Nice to have
Experience in fintech, payments, lending, banking, or other highly transactional environments.
Experience building systems where financial correctness and data integrity are critical.
Experience with event-driven architectures, queues, messaging systems, and asynchronous processing.
Experience with AWS services such as Lambda, ECS/EKS, SQS, SNS, EventBridge, RDS, S3, and CloudWatch.
Experience with Infrastructure as Code, such as Terraform or CloudFormation.
Experience with high-volume transactional systems and distributed architectures.
Experience implementing idempotency, outbox patterns, concurrency control, reconciliation processes, and fault-tolerant workflows.
Experience with observability platforms such as Datadog, Sentry, or similar tools.
Familiarity with DDD, Clean Architecture, Hexagonal Architecture, or similar architectural approaches — with the ability to understand when they are useful and when they add unnecessary complexity.
Experience using modern AI coding assistants, agents, and AI-native development workflows.
Familiarity with LLMs, tool calling, MCP, agentic workflows, or AI integrations is a plus, but AI specialization is not required.
What we offer
The opportunity to work on critical financial products with direct impact on customers and business growth.
High technical ownership and the opportunity to influence how our backend platform evolves.
Meaningful architecture, scalability, reliability, and technical-debt challenges.
An engineering environment where AI is becoming a core part of how we build software.
A collaborative multidisciplinary team across Engineering, Product, Design, QA, Data, and Platform.
100% remote — Argentina or Colombia.
8+ years backend engineering experience; strong Node.js, TypeScript, Express.js; PostgreSQL; AWS; REST APIs; automated testing; CI/CD; observability; ability to work autonomously.
Key Responsibilities
- designing backend services
- building APIs
- optimizing databases
Skills & Tools
Node.js, TypeScript, Express.js, Python, FastAPI, Django, PostgreSQL, AWS, Lambda, ECS, EKS, SQS, SNS, EventBridge, RDS, S3, CloudWatch, Terraform, CloudFormation, Datadog, Sentry
Job Details
- Category: Software Development
- Seniority: Senior Level
- Commitment: Full Time
- Workplace: Remote — Colombia or Argentina or Mexico or Santo Domingo
- Languages: English
About Kiwi Financial Inc
A financial company offering credit products and services. — Industry: Finance