One command, local LLM. Perfect for day one. Dangerous for day ninety if you skipped the concurrency math.
Ollama packages model weights, quantization, and memory management into a single binary. Download a model, serve it with an OpenAI-compatible API at localhost:11434, and point your existing app code at it — swap the base URL, keep everything else.
What It Does
- Run Llama, Mistral, Gemma, Phi, Qwen, DeepSeek, and thousands of GGUF models
- OpenAI-compatible
/v1/chat/completionsendpoint - Automatic GPU layer allocation (CUDA, Metal, ROCm)
- One-command install and model pull
Typical Costs
| Item | Cost |
|---|---|
| Software | Free, open-source |
| Prototyping | $0 on existing laptop or desktop |
| Dedicated GPU (RTX 4090) | ~$1,600 one-time + electricity |
| Cloud GPU (A100 24/7) | ~$860–$1,145/month |
Where It Breaks
Concurrency Collapse
Ollama caps at roughly 4 parallel requests by default. At 10 concurrent users, total throughput can drop to ~41 tokens/second. It’s built for development, not production. That ceiling comes up faster than you’d expect.
Memory Overflow
Long-context requests without explicit limits overflow the KV cache and trigger OOM kills. Configure concurrency and context limits before sharing the instance.
Model Drift (Self-Hosted)
Unlike managed APIs, your model version stays frozen until you manually update it. You’re responsible for re-quantization, testing, and redeployment every 6–8 weeks as new models ship. That’s a real time cost. Plan for it.
When to Choose It
- Local development and prompt testing
- Air-gapped or regulated environments (data never leaves your hardware)
- Internal tools with fewer than 5 concurrent users
- GDPR/DPDP scenarios where API routing crosses borders you can’t accept
Don’t use Ollama for: Customer-facing production at scale. That’s vLLM territory — or managed APIs.
Related
- Self-Hosted AI — When to run your own models
- Data Residency — Where data lives and why it matters
- vLLM — Production-scale inference
- Infrastructure Layer — Hosting decisions
- Silent Agent Failure — Drift you can’t see
- Open WebUI — Browser-based chat interface that runs on top of Ollama
- LiteLLM — API gateway for routing between Ollama and cloud fallbacks
- Model Quantization — The GGUF format Ollama uses and how to choose Q-levels