Sr. Backend Engineer - Node.JS

About Telna

Telna is a global connectivity company that provides eSIM, IoT and mobile network technology to travel brands, mobile network operators and enterprises. Our engineering team builds the platforms and services that let millions of people get connected in seconds, wherever they are in the world.

About the Role

You will be a senior technical owner of the backend services behind our eSIM products. These services power consumer travel eSIM apps and white-labeled apps and web experiences for mobile network operators, all built on a shared multi-tenant platform. They cover catalog and pricing, checkout and payments, order and eSIM lifecycle management, customer data, fraud and risk controls, and the data feeds that analytics and finance teams depend on.

This is a hands-on role with significant architectural influence. You will design services that are correct under failure, integrate with many external systems (payment providers, carrier and eSIM platforms, CRM and marketing tools), and shape how we onboard each new operator onto the platform. You will set backend standards for the team, mentor engineers across experience levels, and work directly with product, frontend, mobile, data and QA.

What You'll Do

• Design, build and operate backend services and APIs in Node.js and TypeScript for catalog, pricing, checkout, orders, eSIM provisioning and usage management.
• Evolve our multi-tenant platform so that each new operator or partner can be onboarded through configuration rather than new code, with per-tenant pricing, branding, feature flags, payment methods and data isolation.
• Build and maintain payment integrations for a range of regional providers, including card processors, mobile money and local gateways. Own idempotency, webhook handling, retries, refunds and reconciliation, so that money movement is correct even when providers fail or repeat callbacks.
• Integrate with carrier and eSIM provisioning platforms and other third-party systems, wrapping unreliable external APIs in clear contracts with timeouts, circuit breakers, queues and replay.
• Own pricing and configuration services, including database-backed pricing rules that product teams can change without a deployment.
• Build fraud and abuse prevention capabilities in the backend: risk scoring, velocity and coupon-abuse checks, payment-failure monitoring and review workflows.
• Design transaction-level data flows so that payment, CRM, analytics and email platform records share consistent identifiers and reconcile cleanly. Work with data and BI teams on event pipelines, warehouse models and reporting accuracy.
• Expose well-documented, versioned APIs to web and mobile clients, and to partner and agent-facing channels such as messaging platforms and AI assistants (for example through MCP-style connectors).
• Drive reliability and performance: observability, alerting, load testing, query tuning, caching and capacity planning.
• Set the standard for testing: unit, integration and contract tests, and automated checks in CI/CD.
• Lead code reviews, write technical design documents, and mentor junior and mid-level engineers.
• Evaluate tools, services and patterns, and make pragmatic build-vs-buy decisions.

What You'll Bring

Required

• 7-8 years of professional backend development, with 6+ years of production Node.js and TypeScript (NestJS, Express, Fastify or similar) on systems with real traffic and real money flowing through them.
• Strong command of API design: REST (and GraphQL where relevant), versioning, pagination, authentication and authorization (OAuth2, JWT, API keys), rate limiting and clear error contracts.
• Deep experience with relational databases (PostgreSQL or MySQL): schema design, indexing, query tuning, transactions, migrations and safe changes to live tables. Working knowledge of Redis or similar for caching and queues.
• Proven experience integrating payment providers, with a solid grasp of idempotency, webhooks, reconciliation, refunds and PCI-conscious design.
• Experience building multi-tenant or white-label systems, including configuration-driven behavior and tenant isolation.
• Experience designing for failure in distributed systems: asynchronous processing, message queues, retries with backoff, dead-letter handling and exactly-once-in-effect semantics.
• Strong testing discipline: unit, integration and contract testing, with tests that run in CI on every change.
• Experience with cloud infrastructure (AWS or similar), containers, CI/CD pipelines and infrastructure as code.
• Production observability experience: structured logging, metrics, tracing and on-call practice.
• Solid grasp of application security: input validation, secrets management, secure handling of personal and payment data.
• Proven ability to mentor engineers, lead technical decisions and communicate with product and business stakeholders, including customers when integration requirements need to be clarified.

Strongly Preferred

• Experience with eSIM, SIM or telecom systems, such as SM-DP+ and carrier provisioning APIs, or with operator (MNO) integrations.
• Experience with fraud, risk or abuse-detection systems, including rules engines and scoring.
• Experience with data warehouses and BI tooling (for example Redshift, Trino or Metabase), and with SQL at analytical scale.
• Experience reconciling data across payment, CRM, analytics and marketing platforms.
• Experience building event-driven systems with Kafka, SQS/SNS or similar.
• Experience with Python, Go or Java alongside Node.js.
• Experience building APIs for AI assistants or agent-driven commerce, including MCP connectors and messaging channels such as WhatsApp.
• Experience with Kubernetes or serverless platforms.
• Prior experience in travel, fintech, e-commerce, telecom or connectivity products.