Senior API & Integration Engineer (E-Wallet, Cloud & AI)

Emerge Limited; Warszawa; On-site; PLN 240,000 - 360,000; Full time

Job summary

Emerge Limited is seeking a Tech Lead / Senior Backend Engineer to own the API mediation layer, cloud-native evolution, and AI integration for a high-throughput global mobile money platform.

You will design API orchestration, lead cloud migrations to microservices on Kubernetes, and build AI workflows with LLMs, RAG pipelines, and vector databases, while enforcing fintech-grade security and resilience.

Qualifications

• Deep mastery of backend development in high-throughput systems.
• Experience with API architecture and enterprise integration patterns.
• Hands-on with orchestration tools like Temporal or Camunda.

Responsibilities

• Own API mediation layer design and implementation.
• Lead cloud migrations to containerized microservices on Kubernetes.
• Build AI workflows and integrate LLM capabilities into fintech stack.
• Ensure fintech-grade security, resilience, and compliant protocols.

Skills

API architecture

Go

Java

Python

C#

Microservices

Kubernetes

Docker

Cloud platforms

Temporal

Camunda

PostgreSQL

MySQL

Kafka

Security protocols

USSD knowledge

Tools

Temporal

Camunda

Kubernetes

Docker

Terraform/OpenTofu

PostgreSQL

MySQL

Kafka

Job description

Emerge in numbers

• 14 years on the market
• 100 people onboard
• 1 6 years of average employment duration
• 50 million transactions daily for mobile wallet
• 1 B$ value transactions daily for mobile wallet
  
• 1 billion mobile money accounts

Are you a senior backend engineer who excels at designing complex API orchestration layers and driving strategic cloud migrations? We are looking for a Tech Lead / Senior Engineer to own the API mediation layer, cloud-native evolution, and AI integration for a high-throughput global mobile money platform.

What you will build:

API Orchestration & Mediation: Design and implement intelligent mediation layers connecting modern web/mobile apps, telecom networks (USSD/SMS), and core e-wallet ledger engines.

Cloud Migration & Architecture: Lead the backend re-architecting of core e-wallet infrastructure, breaking down monolithic systems into scalable, containerized microservices on Kubernetes.

AI & LLM Workflows: Build the integration endpoints and application logic for AI capabilities, orchestrating LLM workflows, RAG pipelines, and vector databases into the fintech ecosystem.

Fintech Security & Resilience: Write highly concurrent code featuring bulletproof transaction rollbacks (Saga pattern), circuit breakers, and fintech-grade security protocols (mTLS, OAuth2, PCI-DSS).

What we are looking for:

Deep mastery of backend development (Go, Java, Python, or C#) in high-throughput, low-latency financial or telecom systems.

Proven track record in API Architecture & Enterprise Integration Patterns (EIP), with hands-on experience using orchestration tools (Temporal, Camunda) or custom mediation layers.

Strong background in cloud migration (AWS/GCP/Azure), Kubernetes, Docker, and IaC (Terraform/OpenTofu).

Expertise in relational databases (PostgreSQL/MySQL) and event-driven streaming (Kafka/RabbitMQ).

Exposure to telecom protocols (USSD, SMSC) or enterprise e-wallet engines (Ericsson MFS, Huawei Mobile Money, Telepin) is a major plus.