Backend Development Servicesfor Scalable and Secure Applications

Kindgeek provides backend development services for regulated financial products: payment engines, core banking APIs, ledgers, and the integrations around them.

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Custom Backend Development Services

Kindgeek covers the full server-side lifecycle, from the first architecture decision to production support. Each service below is available as part of a complete build or as a separate workstream.

Backend architecture and technical consulting

Architecture reviews, system design, technology selection, and a delivery roadmap produced before any code is written, with the reasoning behind each decision documented.

Custom backend application development

Domain modelling, business logic, ledgers, background processing, and admin tooling, built to a defined specification.

API development and system integration

Public, partner, and internal APIs with versioning, rate limiting, sandbox environments, and OpenAPI documentation.

Microservices development

Domain-driven decomposition, clear service boundaries, CQRS, and event sourcing where a full audit history matters.

Database design and optimisation

Double-entry ledger schemas, transaction isolation, ACID guarantees, indexing, and query tuning across PostgreSQL, MySQL, MongoDB, and Redis.

Cloud backend development

AWS, Azure, GCP, and Hetzner deployments with Kubernetes, Docker, Terraform, and Helm, wired into CI/CD from day one.

Event-driven and real-time backends

Apache Kafka, RabbitMQ, NATS, and SQS pipelines for transaction feeds, notification services, and webhook delivery.

Backend modernisation and refactoring

Incremental migration of legacy services, database upgrades, and security refactoring carried out while production keeps running.

Performance optimisation and load engineering

Profiling, caching strategy, sharding, and load testing against defined peak throughput targets.

Backend support and maintenance

Monitoring, incident response, dependency patching, and continuous optimisation after release.

Backend Solutions We Build

These are the system types Kindgeek engineers build and maintain.

Web application backends

Server-side layers for browser products, admin consoles, and merchant portals. Our backend web development services cover authentication, session handling, role management, and reporting.

Mobile application backends

APIs, push notification services, and sync logic for iOS and Android clients, including low-latency response targets for interactive screens.

SaaS platforms

Multi-tenant data isolation, subscription and billing logic, usage metering, and tenant-level configuration.

Enterprise backend systems

Integration-heavy systems connected to existing cores, reporting stacks, and internal services.

Payment and fintech backends

Authorisation, settlement, reconciliation, and multi-rail routing across SEPA, Faster Payments, and SWIFT, with scheme-compliant processing and idempotent retries.

Ecommerce and marketplace backends

Merchant onboarding, transaction reporting, settlement, and dispute management APIs with developer portals and sandboxes.

Data-intensive applications

Event streaming, ETL, warehousing, and real-time analytics for fraud detection and business intelligence.

Real-time and high-load systems

Stateless services, distributed caching, and database sharding so throughput scales linearly without an architectural rewrite.

AI-powered application backends

Python services that expose models, orchestrate inference, and feed analytics pipelines. Our backend application development services extend to the data layer these features depend on.

Backend Architecture Designed for Scale and Reliability

Modular monolith or microservices

A modular monolith keeps early delivery fast and operational overhead low. Microservices add value once independent scaling, separate release trains, or isolated compliance scopes are required. The model is selected during discovery, and the reasoning is documented alongside the architecture.

Event-driven architecture and audit trails

Every state change is stored as an immutable event, so transaction history can be reconstructed at any point and a regulator can replay exactly what happened and when. Kafka, RabbitMQ, NATS, and SQS carry the messages between services.

Distributed systems and resilient service communication

Circuit breakers, fallback routing, and graceful degradation limit the impact of third-party outages, so a platform remains available while a payment rail or KYC provider is unreachable. Payment operations are idempotent by design, with idempotency keys and deduplication giving exactly-once financial semantics under retries.

High availability, failover, and disaster recovery

Multi-zone deployment, health checks, blue-green releases, and canary rollouts keep financial services live during change. Recovery objectives are agreed up front and tested, so continuity planning has evidence behind it.

Caching, database scaling, and data consistency

Distributed caching, read replicas, partitioning, and sharding strategies are chosen against defined consistency requirements, with ledger correctness as the governing constraint.

API Development and Integration

REST API development with versioning, pagination, rate limiting, and OpenAPI specifications.
GraphQL APIs where clients need flexible queries over a broad domain model.
gRPC and service-to-service APIs for low-latency internal communication.
Third-party integration engineering with retry, fallback, and circuit-breaker patterns.
API security and authentication: OAuth 2.0, token lifecycles, mTLS, and signed requests.
API versioning and governance, so existing integrations remain stable across releases.
Webhooks and real-time integrations, including delivery guarantees and replay for missed events.

Cloud-Native Backend Development

AWS, Azure, Google Cloud, and Hetzner deployments matched to data residency requirements.
Containers and orchestration with Docker, Kubernetes, and Helm.
Serverless components for event-driven workloads with variable load profiles.
Managed cloud databases and caching layers with backup and failover configured.
Infrastructure as code using Terraform, with GitHub Actions, GitLab CI, Jenkins, or ArgoCD pipelines.
Auto-scaling and load management tuned to real traffic curves.
Cloud cost optimisation through right-sizing and workload scheduling.

AI-Ready Backend Development

Model-driven features depend on the server-side layer around them for reliability, observability, and compliance. Kindgeek builds that layer.

Backend infrastructure for AI applications

Queueing, rate control, cost tracking, and graceful degradation when a provider throttles.

LLM and model integrations

Exposed as internal services with clear contracts and timeouts.

Vector databases and retrieval infrastructure

Search over your own documents and transaction data.

Tool and API layers

Give AI agents safe, permissioned access to business operations.

Real-time inference pipelines

Built on the same event streaming stack used for transaction feeds.

AI data and observability infrastructure

ETL into the warehouse, prompt and response logging, and quality metrics.

Secure and Compliance-Ready Backend Development

Authentication and authorisation, including multi-factor flows and SCA for payment operations.
Role-based and attribute-based access control across services and admin tooling.
Encryption at rest and in transit, with secrets managed in HashiCorp Vault or AWS KMS.
API security and rate limiting, plus OWASP-aligned hardening verified with OWASP ZAP.
Secure software supply chain, with dependency and container scanning through Trivy in CI.
Audit logging and traceability, so every privileged action has an owner and a timestamp.
Compliance-ready architecture for PCI DSS, ISO 27001, SOC 2, and GDPR.

Performance, Reliability, and Observability Engineering

Performance and load engineering

We agree throughput and latency targets before build, then verify them. Load and stress testing, database query optimisation, caching and content delivery, horizontal and vertical scaling, and failover drills all feed into reliability targets and SLOs that are measurable in production.

Observability in production

Backend work continues after deployment. We instrument services with Grafana, Prometheus, ELK, and Datadog to deliver application performance monitoring, centralised logging, metrics and distributed tracing, error and incident monitoring, production health dashboards, and alerting tied to a defined incident response path.

Backend Modernisation Without a Full Rewrite

Kindgeek modernises legacy systems in increments, so the platform stays in production while the architecture improves.

Legacy backend assessment

Code, data model, dependency, and security review with a prioritised risk list.

Monolith modernisation

Extracting modules with clean boundaries before any service is split out.

Microservices migration

Moving the highest-value domains first and routing traffic gradually.

Database modernisation

Schema redesign, engine upgrades, and migration with reconciliation checks.

Cloud migration

Containerisation, infrastructure as code, and environment parity.

API modernisation

New contracts published alongside legacy endpoints, with a deprecation timeline.

Performance and security refactoring

Hot paths, query plans, and vulnerable dependencies addressed together.

Incremental delivery throughout

Each release is reversible and the platform stays live.

Our Backend Development Process

Requirements and architecture discovery

Business goals, regulatory scope, integration inventory, and non-functional targets.

System design and technology selection

Architecture documented, stack chosen, risks named.

Database and API design

Schemas, contracts, and sandbox environments published early for client teams.

Infrastructure and security planning

Environments, secrets, network segmentation, and compliance boundaries.

Backend development

Iterative delivery with code review and static analysis on every merge.

Automated testing and performance validation

Unit, integration, contract, and load tests in CI.

Deployment and production readiness

Blue-green or canary release, runbooks, and health checks.

Monitoring and continuous optimisation

Dashboards, alerting, and a backlog driven by production data.

Backend Development Technology Stack

Technology selected for reliability, auditability, and regulatory fit. Language choice is a business decision as much as a technical one.

Programming languages

Java, Python, Node.js, PHP

Backend frameworks

Spring Boot, Quarkus, Django, FastAPI, Flask, NestJS, Express, Fastify, Laravel, Symfony

SQL and NoSQL databases

PostgreSQL, MySQL, MongoDB, Redis

Messaging and streaming

Apache Kafka, RabbitMQ, Amazon SQS, NATS

Cloud platforms

AWS, Azure, Google Cloud, Hetzner

Containers and orchestration

Docker, Kubernetes, Terraform, Helm

API technologies

REST, GraphQL, gRPC, webhooks, OpenAPI

Monitoring and DevOps

Grafana, Prometheus, ELK, Datadog, GitHub Actions, GitLab CI, Jenkins, ArgoCD

Security and compliance

HashiCorp Vault, AWS KMS, OWASP ZAP, Trivy, PCI DSS, ISO 27001, SOC 2, GDPR

Backend Development for Your Industry

Sectors where Kindgeek has delivered production backend systems.

Fintech and payments

Payment engines, merchant onboarding, KYC and AML orchestration, multi-rail routing, settlement, and reconciliation for licensed providers.

Banking and neobanks

Core banking APIs, account ledgers, balance management, interest calculation, and statement generation.

B2B platforms and marketplaces

Partner APIs, transaction processing, and integration layers built for network scale.

Card issuing and processing

Card lifecycle management, BIN configuration, authorisation processing, tokenisation, and 3DS server integration.

Backend Development Case Studies

payabl.

Core payment engine, merchant onboarding APIs, KYC and AML services, and the settlement pipeline. A full backend ecosystem processing transactions across multiple payment rails.

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HyperJar

Event-driven backend powering mini-accounts, real-time balance management, and payment processing, serving mobile and web clients with sub-100ms API responses.

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Tradeshift

Eight Kindgeek engineers contributed over three years to backend services handling transaction processing and partner integrations.

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Engagement Models

End-to-end backend development

Kindgeek owns architecture, delivery, deployment, and production support for the whole system.

Architecture, build and deployment in one team
Monitoring and incident response after release
Single point of accountability across every layer
Work breakdown estimate produced after discovery

Dedicated backend team

A stable long-term team working inside an existing process, roadmap, and release cycle.

Stable team over a multi-year engagement
Works to your process and release cycle
Reports into your roadmap and planning
Scales as the platform grows

Staff augmentation

Individual backend engineers added to an existing team for capacity or a specific technology skill.

Java, Python, Node.js or PHP specialists
Added for capacity or a specific skill gap
Works to your conventions and code review
No change to your existing process

Modernisation partnership

A team focused on legacy assessment and incremental migration, running in parallel with feature delivery.

Legacy assessment with a prioritised risk list
Incremental migration, production stays live
Runs in parallel with feature delivery
Each release reversible

Architecture consulting and audit

A time-boxed review of an existing system, producing findings, risks, and a prioritised action plan.

Time-boxed review of an existing system
Code, data model, dependency and security review
Findings and risks documented with reasoning
Prioritised action plan on delivery

Backend Development Cost and Timelines

What affects the cost

The main drivers are the number of external integrations, regulatory scope such as PCI DSS, architecture choice, non-functional targets for throughput and latency, data migration volume, and the engagement model selected.

New build compared with modernisation

A new backend carries design and infrastructure setup cost and starts free of legacy constraints. Modernisation typically spreads spend across releases and adds data migration and parallel running to the scope.

What affects the timeline

Delivery pace depends on integration readiness, scheme and provider certification cycles, data migration complexity, and approval cycles on both sides. Kindgeek sequences work so that a usable increment ships early.

Common Questions About Backend Development

What are backend development services?

What is included in backend development?

How much does backend development cost?

Should we use a monolith or microservices?

Can you modernise an existing backend without a full rewrite?

Can you build an AI-ready backend?

Start Your Backend Development Project

Send the system requirements: throughput targets, integrations in scope, and applicable regulatory standards. Kindgeek responds within 24 hours with an architecture perspective and a team recommendation. A short discovery session is enough to produce a costed estimate.

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