About er400.io

Who I Am

Ernest Rozložník | IBM i & Linux Systems Architect | Open Source Advocate
For 25+ years, I’ve been bridging the gap between legacy IBM i (AS/400) systems and modern technologies. As the founder of er400.io, I specialize in system integration, API development, and open-source innovation—helping businesses unleash the full potential of their IBM i environments while keeping them agile in today’s tech landscape.

I’m not just a consultant; I’m a problem solver who thrives on making IBM i “talk” to the modern world—whether it’s Redis, Salesforce, web apps, or cloud services.

My Expertise

Core Strengths

  • IBM i (AS/400) Mastery:
    • Languages: RPG (ILE, Free), CL, SQL (UDTFs, UDFs), C, Python, PHP, Perl, BASIC.
    • Integration: Building APIs to connect IBM i with Redis, web apps, ERPs, and cloud platforms.
    • Open Source on IBM i: Pushing boundaries with PASE, IFS, and open-source tools (Node.js, Python, Redis).
  • Linux/Unix Integration:
    • Cross-platform scripting, system automation, and hybrid IBM i/Linux solutions.

What I Build

  • Custom UDFs/Services: Like creating IBM i UDFs for Redis to enable real-time caching.
  • Legacy Modernization: Extending RPG apps with REST APIs or Python microservices.
  • Performance Optimization: SQL tuning, service program modularization, and IFS-based workflows.

My Story

I founded er400.io to merge my deep IBM i expertise with a mission: help businesses break free from “green-screen jail” without ditching their rock-solid IBM i backbone.

  • 25+ Years of Hands-On Work: From legacy RPG to cutting-edge open source on IBM i.
  • Open Source Evangelist: Proud contributor to the IBM i open-source community, advocating for tools like Python, PHP, and Redis on PASE.
  • Real-World Focus: No theoretical fluff—just practical, scalable solutions (like my Redis UDFs for IBM i).

What I’m Working On

  • Long-Term Project @ ISSI: Integrating IBM i systems with modern APIs and cloud tools.
  • Open-Source Labs: Experimenting with Redis, FastAPI, and RPG-free IBM i microservices.
  • Always Open to Collaborate: Need an API? A hybrid IBM i/Linux solution? Let’s talk!

Why Work With Me?

  • No-Nonsense Approach: I speak RPG and Python fluently—no “integration mysticism.”
  • Open Source Pragmatist: I use the right tool (even if it’s not IBM’s default).
  • Your System, Modernized: Without costly rip-and-replace.

Let’s Connect: Contact