Senior Backend Engineer-Payments

CXM; Polska; Remote; PLN 335,000 - 469,000; Full time

Benefits offered by this job

Fully remote within GMT to GMT+4

Ownership of connector layer

Challenging engineering problems

Corporate AI tooling

Job summary

CXM is seeking a Senior Backend Engineer to own the connector and adapter layer for our payment providers, enabling configuration-based integrations rather than bespoke builds. You will migrate flows to server-to-server and embedded methods, and ensure reliable, observable transaction status across the system.

You will partner with the orchestration platform team to define the required platform behavior, design scalable patterns, and drive improvements across reconciliation, status handling, and

Qualifications

• 5+ years in backend engineering with payments domain.
• Strong in TypeScript/Node.js and relational databases.
• Experience with third-party APIs integration and idempotent status handling.
• Ability to own architecture decisions and drive improvements.
• English and Russian at working level.

Responsibilities

• Build and own the connector and adapter layer for provider integrations.
• Migrate payment methods to server-to-server and embedded flows; measure results.
• Own downstream of orchestration layer: reconciliation and status handling.
• Ensure end-to-end reliable transaction status via idempotent processing and polling.
• Build observability over transaction status and provider performance across the estate.
• Define required behavior from orchestration platform: state machines, polling, routing.

Skills

Backend engineering

TypeScript

Node.js

Relational databases

Idempotency

System design

English

Russian

Async status handling

Tools

.NET

APM

Rails

Job description

We are an international broker. Our clients fund and withdraw through roughly 60 payment methods across Asia, Africa, LATAM and the Middle East.

Payments is now a standalone function, and we are building the team around it.

We are looking for a Senior Backend Engineer who will own our connector layer and everything downstream of it: building a canonical adapter layer so that providers plug in rather than get built one by one, moving payment methods to server-to-server and embedded flows, and making transaction status reliable and observable across the estate.

You will also be the payments function's technical counterpart to the orchestration platform team: the behaviour we need from the platform is specified here, argued here and reviewed here.

Your responsibilities will be:

• Building and owning the connector and adapter layer, so that adding or replacing a provider becomes configuration and a thin adapter rather than a new integration each time
• Migrating payment methods from redirect flows to server-to-server and embedded flows where the provider supports it, and measuring the result
• Owning everything downstream of the orchestration layer: reconciliation, transaction status handling on our side, method configuration and payment flows into the client portal
• Making transaction status reliable end to end, through active status polling, idempotent processing and reconciliation
• Building observability over transaction status and provider performance across the estate
• Specifying the behaviour we need from the orchestration platform: transaction state machine, idempotency, polling, routing and cascading rules. You design it, argue for it and review what comes back
• Supporting integration work for our card programme
• Extending the same integration set to acquired entities as configuration rather than a new build each time

Requirements

• 5+ years in backend engineering, strong in TypeScript, Node.js, comfortable in relational databases
• Production experience with payment systems: authorisation, callbacks, refunds, reconciliation and retry behaviour
• Practical understanding of idempotency, asynchronous status handling, transaction state machines and designing for partial failure. This is the core of the role rather than a detail, and you will both build against it and specify it
• Experience integrating third-party APIs of uneven quality, including working directly with a provider's integration team to resolve what the documentation does not answer
• The ability to own a service rather than close tickets: architecture decisions, standards and root cause fixes
• English and Russian at a working communicative level

Will be a significant plus

• Exposure to .NET for work touching the client portal
• Experience with APM and local rails in Asia, Africa or LATAM rather than cards alone
• Experience with bank transfer rails, virtual accounts, QR-based methods, mobile money etc
• Event-driven patterns in production: transactional outbox, idempotent consumers, sagas
• Background in brokerage, crypto payments, orchestration or another high-volume payments environment; on the provider side, at a PSP, gateway or payment company
• Active use of AI tooling in daily work
• Ability to work independently and make decisions without constant oversight
• Proactive mindset: willingness to propose improvements, fixes, new approaches

What the first year looks like

• In the first months you take over the integration codebase with a documented handover, strengthen transaction status handling, and ship your first server-to-server integration
• By mid-year the adapter layer is in place, new providers go live against it rather than as one-off builds, and transaction status and provider performance are observable across the estate
• In the second half the migration to server-to-server and embedded flows runs as a programme across methods, and the same integration set starts extending to our other entities. As the team grows, a Systems Analyst takes over instrumentation and verification while integration engineering stays with you

Recruitment process

• HR interview, covering background, motivation and fit
• Technical interview on backend engineering and the payments domain
• Home task as a case from the real needs
• System design and problem-solving interview, covering integration design, failure handling and status modelling
• Final interview with senior stakeholder

Benefits

• Fixed monthly compensation of [based on experience]
• Fully remote work within GMT to GMT+4, with no relocation required
• Ownership of the connector layer and everything downstream, with direct influence on what the orchestration platform becomes
• Engineering problems that are not CRUD: asynchronous status across dozens of providers, partial failure, and local payment rails in emerging markets
• Scope that grows with the business: a card programme, new entities and new payment products
• Corporate AI tooling as part of the working process