Find Your Route

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How I Used Gemma 4

The Architectures We Chose & Why

To power our real-time commuter co-pilot, we designed a Hybrid Intelligent Routing System leveraging two primary Gemma 4 architectures:

Primary Brain: Gemma 4 31B Dense (google/gemma-4-31b-it:free)
- Role: High-throughput Cloud Reasoning Engine.
- Why it fits: Crafting navigation itineraries requires highly accurate multi-step reasoning. Gemma 4 31B Dense excels at reading raw JSON databases of train lines, understanding platform interconnections, and formatting instructions in elegant, bite-sized markdown that is easy for commuters to read on the move.
Local Fallback: Gemma 4 E2B (gemma4:e2b)
- Role: Resilient Edge Deployment via Ollama.
- Why it fits: The E2B model is highly optimized for local/offline deployment on restricted hardware (like station ticketing computers or local server nodes). It offers extremely high reasoning efficiency with a small memory footprint, ensuring that even if public internet connectivity drops in underground terminals, the local fallback is triggered in less than 500ms to guide commuters safely.

The Orchestration Pipeline

Pipeline

Engineering Challenges & Breakthroughs

Challenge 1: The Local Memory Bottleneck (8GB RAM Limit)

The Problem: During local testing, the system would regularly freeze and throw Out-Of-Memory (OOM) crashes. Ollama would struggle to run Gemma 4 concurrently with Docker, VS Code, and multiple open browser tabs.
The Fix: We initially had to close all background apps and tabs just to keep Ollama alive. Recognizing that this was a bad user experience, we researched and implemented the Low-Memory Profile (gemma4-lowmem).

Challenge 2: Docker Container Networking & Redis Configuration

The Problem: Orchestrating a FastAPI backend with a Redis cache using Docker Compose caused repeated connection failures, with the backend unable to reach the Redis container during startup.
The Fix: We initially configured Redis using localhost / 127.0.0.1, but that did not work because each Docker container runs separately. We fixed it by changing the Redis host to redis (REDIS_HOST=redis), removed password setting, and updating the Docker setup so the backend could connect to Redis properly.

Images of the app!

Submitted by Afreen Hossain

Top comments (1)

shogun444 profile image

shogun 444

Full-Stack Engineer "A smooth sea never made a skilled sailor."

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• May 24

Really nice concept. Clean, practical, and easy to understand without unnecessary complexity. Projects solving small real-world problems like this are honestly the most useful ones.