Back End Developer
ImpoNexpo · Lagos State, Nigeria
Apply & track with Apply EdgeImponexpo is building the intelligence and execution infrastructure for global commerce.The company develops AI-native systems, platforms, research, data infrastructure, economic intelligence, and execution capabilities designed to make cross-border commerce more intelligent, verifiable, interoperable, and executable across countries, institutions, businesses, machines, and the physical world.Its work spans Crossbotra, its AI-native commerce execution environment; Crobotra, its commerce-native intelligence layer; commerce graphs; economic world models; AI evaluation; autonomous agents; machine commerce; payments; logistics; regulatory intelligence; and other technologies required to execute complex global trade.Imponexpo also maintains a broader research program around Intelligent Commerce and Computational Commerce.About the RoleWe are looking for a highly practical Backend Engineer to join a small product and technology team in Lagos.You will build the APIs, databases, business logic, authentication systems, workflows, integrations, and backend infrastructure that power our products.This is not a role focused only on creating basic CRUD APIs. We are looking for an engineer who thinks carefully about system architecture, security, data integrity, scalability, reliability, permissions, observability, and maintainability.You will work closely with Frontend Engineers, Product Designers, AI/ML Engineers, and other team members to turn complex product requirements into reliable production systems.What You Will Work OnDesign, build, test, deploy, and maintain backend services and APIs.Develop business logic, workflow systems, and application services.Design and maintain relational and document-oriented databases.Build secure authentication, authorization, identity, and permission systems.Develop APIs supporting web, mobile, internal, partner, and machine-facing applications.Build systems supporting multiple users, organizations, roles, and access levels.Develop onboarding, account, transaction, notification, and workflow infrastructure.Integrate payment providers, communication platforms, analytics systems, external APIs, and third-party services.Build queues, background jobs, scheduled tasks, asynchronous workflows, retries, and event-driven processes.Work with Frontend Engineers to define reliable API contracts.Collaborate with AI/ML Engineers to integrate models, inference services, embeddings, search, recommendations, and other intelligence capabilities.Build search, filtering, ranking, and retrieval capabilities.Design systems involving companies, products, users, transactions, logistics, regulations, payments, and other structured business entities.Maintain data validation, integrity, traceability, and auditability.Implement logging, monitoring, error tracking, metrics, and observability.Diagnose production problems and identify root causes.Improve performance, reliability, security, and scalability.Write clean, modular, maintainable, documented, and testable code.Participate in code reviews and contribute to engineering standards.Support deployment, infrastructure, security, and DevOps-related work where necessary.Required QualificationsStrong practical experience with JavaScript and/or TypeScript.Strong backend experience using Node.js.Experience with NestJS, Express, Fastify, or comparable backend frameworks.Strong understanding of REST APIs and backend architecture.Strong practical experience with relational databases, preferably PostgreSQL.Experience designing database schemas, relationships, indexes, queries, and migrations.Experience with an ORM or database toolkit such as Prisma, TypeORM, Drizzle, Sequelize, or similar.Strong understanding of authentication, authorization, sessions, tokens, API keys, and role-based access control.Understanding of application-security fundamentals.Experience integrating third-party APIs and external services.Strong working knowledge of Git and collaborative development workflows.Understanding of asynchronous programming, queues, and background processing.Ability to write and maintain automated tests.Ability to debug backend problems independently.Strong attention to reliability, data integrity, security, and engineering quality.Ability to translate product requirements into sound technical systems.Ability to work independently, manage priorities, and deliver without constant supervision.Must be based in Lagos or willing to relocate to Lagos and work fully onsite.This is an onsite role. Hybrid and work-from-home arrangements are not available.Preferred QualificationsExperience building and operating production backend systems used by real customers.Advanced experience with PostgreSQL.Experience with MongoDB or other document databases.Experience with Redis, caching, sessions, and queues.Experience with RabbitMQ, Kafka, SQS, BullMQ, or comparable messaging systems.Experience with event-driven and asynchronous architectures.Experience building multi-tenant SaaS or enterprise applications.Experience with complex role-based or attribute-based access-control systems.Experience building marketplaces, fintech, logistics, payments, enterprise software, workflow products, AI-native applications, or B2B platforms.Experience integrating payment gateways, banking APIs, or transaction systems.Experience designing audit logs and traceable workflows.Experience handling large datasets and performance-sensitive database workloads.Experience with search technologies such as Elasticsearch, OpenSearch, or similar.Familiarity with vector databases, embeddings, and semantic search.Exposure to graph databases such as Neo4j or comparable technologies.Familiarity with knowledge graphs and relationship-oriented data modelling.Experience integrating AI/ML models into production systems.Familiarity with Python for data or AI integration.Experience with Docker and containerized development.Experience with AWS, Azure, Google Cloud, or comparable infrastructure.Familiarity with Kubernetes and CI/CD pipelines.Experience with Linux server environments.Experience with webhooks, rate limiting, caching, retries, throttling, and resilience patterns.Familiarity with microservices and distributed systems.Experience with structured logging, tracing, monitoring, and observability.Experience with secrets management, encryption, and secure credential handling.Experience building products involving multiple countries, currencies, languages, or regulatory environments.Experience working in an early-stage company or small engineering team.Experience taking backend systems from prototype to production and ongoing scaling.What We Care AboutWe care more about what you can build and operate reliably than the number of technologies listed on your CV.We want engineers who ask more than:“Does the API work?”You should also think about:Is the data model correct? Is it secure? Can it scale? Can failures be recovered from? Can actions be traced? Are permissions enforced correctly? Is the system maintainable?You should be able to take a requirement through:Understand → Model → Architect → Build → Test → Deploy → Observe → ImproveWe value engineers who can think independently, communicate clearly, challenge weak technical approaches constructively, and take ownership of outcomes.Working StyleThis role requires a high level of ownership, independence, discipline, focus, and commitment to quality.You should be comfortable working deeply and independently while collaborating closely when architecture, product, security, or integration decisions require discussion.There may be periods around important product milestones when additional effort or extended hours are required.Location and Employment