Sergey Vareyko / Custom Business Systems

Custom business software development: claims, case management, rule engines and lending CRM

This page is for organizations whose process is the product: insurers and claims administrators, public agencies running investigations, lenders, operators of physical infrastructure. When off-the-shelf software makes the process bend to it, custom business software development is the alternative, and I have built such systems in insurance, the public sector, fintech and telecom.

What I build

  • Multi-tenant platforms. Tenants with isolated databases per service, resolved from the subdomain, and per-tenant database provisioning.
  • Case and workflow management. Claims, tasks, documents and communication in one place; investigation pipelines from tip to claim to hearing, with generated letters and auto-filled PDF forms.
  • Configuration instead of code. Configuration portals where clients define product lines, data models, intake forms and rules, and low-code builders where business users assemble CRM screens and data-entry forms bound to live data.
  • Rule engines and validation. Logical analysis of client-specific rules and configurations to find issues, including ones already present in the live environment; declarative rule sets combined with Java rules and environment-specific overrides, as in the AMS merchant onboarding platform described under e-commerce. At TouchCommerce I built a framework for managing and deploying business rules across client platforms.
  • Access control and audit. Role-based access (for example admin, director and investigator), Keycloak-based multi-tenant permissions with a management UI, and audit trails with per-user revision history.
  • Communication and documents. Two-way SMS, queued email, document templates, PDF generation and file storage on S3.
  • Integrations. Banking, crypto, FX and CRM providers, webhook-driven flows, REST and GraphQL APIs.
  • Specialized editors. A 3D editor for modeling equipment on communication towers, with AutoCAD drawing output.

The operations side — admin portals, monitoring, environment tooling — is on the internal tools page.

How I work

I translate business requirements into an architecture: the structure of the solution, the stack, the integrations and the scalability approach. As a solution architect I have done this in technical presales for new client engagements, four of which became won business, and then stayed on to guide the implementation of what I designed. On delivery projects I have led the engineering side, mentored engineers and run code reviews.

Not every system starts from scratch. On the SNAP case management system I migrated a legacy Spring and Hibernate monolith to Spring Boot module by module without freezing feature work. You receive a working system early, then iterations; a database whose history lives in versioned migrations; an audit trail; and configuration surfaces that let your staff change forms and rules without a release. Working inside an enterprise system that already exists is a normal part of this work.

Projects in this domain

Iotatech Claims (CLM) — Software Engineer, 2016–2018. A multi-tenant, pay-per-use claims management SaaS for insurers and third-party administrators: six microservices behind an API gateway and three Angular portals sharing one component library. I built two-way SMS with claimants over Twilio (16 merged PRs), migrated date and time handling to UTC across five services and three portals, and implemented configurable document templates with PDF generation.

MDHS Program Integrity — SNAP Fraud Case Management System — Lead Software Engineer, 2016–2018. Built by NSPARC (Mississippi State University) for the Mississippi Department of Human Services: fraud tip intake, EBT transaction search, claims with charge and determination letters, administrative hearings and a full audit log. I designed a search layer that runs on Solr or direct SQL by one config flag and introduced 168 Liquibase changesets.

Business Rules Validation Tool — Jr. Engineer. A tool that checks client-specific rules and configurations through logical analysis of custom expressions and detects issues in the real environment. It started as a browser extension and moved to a Java backend when validation grew more complex.

Root Studio — Lead Software Engineer, 2020–2021. A low-code studio and integration backend for a multi-tenant fintech lending CRM: a GrapesJS page and form builder with 20+ custom data-bound components, Keycloak access control, lending modules for deals, fees, contacts, referral partners, tasks and notes, and about 100 REST endpoints plus GraphQL connected to Plaid, Coinbase, Currencycloud, Wealthica and HubSpot.

Tower Management Portal — Lead Software Engineer, 2019–2020. Management of existing communication towers and a tool for modeling antennas, equipment and cables. The core was a 3D editor built with React and Three.js that had to be fast and stable on any device, support most modeling formats and produce AutoCAD drawings.

Frequently asked questions about custom business software development

Can our staff change forms and rules without a developer?

That is usually the point. On the claims platform insurers configure product lines, data models, intake forms and rules themselves; on Root Studio business users build CRM screens in a visual editor; on the payment onboarding platform new products and partners are added through configuration rather than code.

We already have a legacy system. Rewrite or migrate?

Both are possible. A module-by-module migration keeps the business running and features shipping, as on the SNAP system; a one-shot rebuild on a current stack suits a smaller application, as with Bolimond. The choice depends on the size of the system, how well its behavior is understood, and how much change the business can absorb at once.

How long does a system like this take?

It depends on scope: the number of roles and workflows, the integrations, whether there is data to migrate, and whether it is multi-tenant. I estimate once the requirements are on the table.

Where does the data live, and how is access controlled?

Where your business needs it: the claims platform and the tower portal ran on AWS, and the multi-tenant platforms kept each tenant's data in its own databases. Access is role-based and changes go to an audit trail per user. Hosting, repository and support arrangements are agreed at the start.

Need an engineer with experience in custom business software development? Write to me — a few lines about the task are enough — or look through my CV.