Case — Dux Logistics MVP (Logistics & Document Workflow Platform)

Type: Freelance (client: Dux Logistics) Role: Full Stack Developer and product/architecture owner Status: Complete, in UAT with the client Stack: Java, Spring Boot, Angular, PostgreSQL, Docker Compose, deployed on an Oracle Cloud VPS

Context and problem

The client ran logistics and document processes on an expensive, generic corporate BPM platform (TOTVS Fluig-style): request creation, group handling queues, staged approvals, attachments and SLAs. The goal was to replace it with a lean, in-house product specialized in the logistics domain — without paying the cost (financial and complexity) of a generic BPM.

Solution

A corporate web product for logistics operational workflow, designed by reverse-engineering the legacy system's screens:

Request creation with per-type forms (controlled schema, not a free-form editor)
Individual and group task inbox, with handling, forwarding, return and reassignment
Single or multi-stage approval, workflow parameterizable by request type
Document, attachment and document checklist management
Complete request timeline (audit trail and change history)
Operational dashboard with delay, deadline and volume indicators; filters, export and batch operations
Organizational records (company, unit, department, groups) and operational records (clients, document types, priorities)
In-app and e-mail notifications

Architecture and technical decisions

Explicit product decision: workflow parameterizable by stages, rules, groups and SLA — no open BPMN and no generic low-code. Controlled scope = a viable MVP for a solo developer.
Dynamic forms with a controlled schema: fields configurable per request type with standardized components, avoiding the trap of an unbounded "form builder".
Java + Spring Boot on the backend and Angular on the frontend, following an in-house development rules guide versioned in the repo (code standards, tests and API contract).
PostgreSQL with modeling for a per-request audit trail.
Docker Compose for dev and production, with a specific compose file for deployment on an Oracle Cloud VPS (near-zero infrastructure cost on the free tier).
JVM/query optimization plan versioned and applied (PLANO-OTIMIZACOES-JAVA.md).

Challenges and solutions

Gathering requirements without access to the original system: requirements inferred from real screenshots of the operation, validated with the client and documented in a detailed product plan before coding.
Balancing "complete product" vs. "Fluig clone": trade-offs documented; anything too generic was left out of the MVP in favor of depth in the logistics domain.
Operating as a full-cycle freelancer: from the commercial proposal (sales PPTX) to the VPS deployment, covering product, UX, architecture and code.

Results and impact

Replacement of a corporate BPM license with a specialized in-house product [savings TO CONFIRM]
Processes with full traceability and SLAs visible to management
Parameterizable foundation that lets the client create new request types without development work