Enterprise teams are moving AI workloads in-house. The reasons: data sovereignty, cost control at scale, and regulatory compliance. Here’s the architecture.

Why enterprises self-host

Concern	Cloud API	Self-hosted
Data leaves your network	Yes	No
GDPR compliance	Requires DPA + SCCs	Automatic
Cost at scale	$10K+/month	Fixed hardware cost
Model control	Provider decides updates	You control versions
Uptime	Depends on provider	You control SLA
Customization	Limited	Full (fine-tuning, custom models)

The architecture

                    ┌─────────────────────────┐
                    │     Load Balancer        │
                    │    (Nginx / Traefik)     │
                    └──────────┬──────────────┘
                               │
              ┌────────────────┼────────────────┐
              │                │                │
    ┌─────────▼──────┐ ┌──────▼───────┐ ┌──────▼───────┐
    │  vLLM Instance  │ │ vLLM Instance │ │ vLLM Instance │
    │  (GPU Node 1)   │ │ (GPU Node 2)  │ │ (GPU Node 3)  │
    │  Qwen 3.5 27B   │ │ Devstral 24B  │ │ Codestral 22B │
    └────────────────┘ └──────────────┘ └──────────────┘
              │                │                │
              └────────────────┼────────────────┘
                               │
                    ┌──────────▼──────────────┐
                    │    OpenAI-Compatible     │
                    │         API              │
                    └──────────┬──────────────┘
                               │
         ┌─────────────────────┼──────────────────────┐
         │                     │                      │
    ┌────▼─────┐        ┌──────▼──────┐        ┌─────▼──────┐
    │  Aider   │        │ Continue.dev │        │  OpenCode  │
    │ Terminal │        │   VS Code    │        │  Terminal  │
    └──────────┘        └─────────────┘        └────────────┘

Hardware sizing

Team size	Hardware	Models	Monthly cost
1-5 devs	Mac Mini M4 32GB	Qwen 3.5 27B + Codestral	~$50 (amortized)
5-15 devs	RTX 4090 workstation	Qwen 27B + Codestral	~$105 (amortized)
15-50 devs	2x A100 server	Devstral 2 123B	~$500 (cloud)
50+ devs	GPU cluster	Multiple models	Custom

See our GPU memory planning guide for exact VRAM calculations and our inference cost calculator for break-even analysis.

Model selection

Use case	Model	Why
Coding agent	Devstral Small 24B	Best coding quality at 24B, 256K context
Autocomplete	Codestral 22B	Purpose-built for FIM, fastest
General chat	Qwen 3.5 27B	Best all-rounder at this size
Reasoning	DeepSeek R1 14B	Best reasoning at small size
Frontier quality	Mistral Large 2 123B	Single-node, EU-based company

All available via Ollama (easy) or vLLM (production).

Inference engine

Use vLLM for multi-user production serving. It provides:

• OpenAI-compatible API (drop-in replacement)
• Continuous batching for high throughput
• Prefix caching for shared prompts
• Tensor parallelism for multi-GPU

For single-user or small teams, Ollama is simpler. See our inference engine comparison.

Security

Self-hosting eliminates third-party data transfer but introduces new responsibilities:

• Network isolation — AI servers should be on a separate VLAN
• Access control — API keys or OAuth for the inference endpoint
• Model integrity — verify checksums when downloading weights
• Logging — observability for audit trails
• Updates — you’re responsible for patching and model updates

See our AI security checklist.

Connecting developer tools

Once your inference server is running, connect your team’s tools:

# Aider
aider --model openai/devstral-small --openai-api-base http://ai-server:8000/v1

# Continue.dev (VS Code)
# Set provider to "openai" with baseURL "http://ai-server:8000/v1"

# OpenCode
opencode --provider ollama --model devstral-small:24b

See our free AI coding server guide for step-by-step team setup.

The hybrid approach

Most enterprises don’t go 100% self-hosted. The practical approach:

• Self-host for routine coding (autocomplete, simple edits) — free after hardware
• Cloud API for complex tasks (architecture decisions, security reviews) — Claude Opus or GPT-5
• EU provider for sensitive data — Mistral API with EU data residency

This gives you cost control on 80% of usage while keeping access to frontier models for the hardest 20%.

Total cost of ownership

When comparing self-hosted vs cloud API, include all costs:

Cost category	Cloud API	Self-hosted
Model access	Per-token pricing	Free (open weights)
Hardware	$0	$50-500/mo (amortized)
Electricity	$0	$20-50/mo for GPU server
Ops time	$0	2-4 hrs/week
Updates	Automatic	Manual
Scaling	Automatic	Manual

For a team of 10 developers doing 50K requests/day:

• Cloud API (Claude Sonnet): ~$300/month
• Self-hosted (Devstral 24B on A100): ~$200/month (cloud GPU) or ~$100/month (own hardware)

The break-even point is typically around 20K requests/day. Below that, cloud APIs are simpler and cheaper. Above that, self-hosting starts to make financial sense.

Getting started

The fastest path to self-hosted AI:

1. Install Ollama on any machine (5 minutes)
2. Pull a model: ollama pull devstral-small:24b
3. Connect Aider or Continue.dev: point to http://localhost:11434
4. Start coding with free, private AI

Graduate to vLLM when you need multi-user serving, and to dedicated GPU hardware when you need consistent performance.

Related: Self-Hosted AI for GDPR · How to Set Up a Free AI Coding Server · How to Serve LLMs with vLLM · Best AI Coding Agents for Privacy · Best Cloud GPU Providers