How to Build a Self-Hosted AI Gateway With LiteLLM and Open WebUI

If you've ever self-hosted AI tools, you know how quickly things get messy.

One app talks to OpenAI. Another uses Anthropic. You spin up Ollama locally and now there's a third endpoint to manage. Authentication is different everywhere. Switching models means rewriting integration code. And before long, you're spending more time maintaining glue code than actually building anything.

I ran into this exact problem — so I built a cleaner setup.

The idea is simple: put a single gateway in front of every provider, so the rest of your stack only ever talks to one API.

I open-sourced the full working implementation here:

🔗

├── Docker-compose.yml

├── litellm-config.yml

└── .env

Each file has a distinct job: Docker Compose orchestrates services, LiteLLM config handles routing and model aliases, .env stores secrets and runtime configuration.

Setting Up Environment Variables

Your .env file is where provider credentials live. Create or update it in the project root:

LITELLM_MASTER_KEY=sk-very-strong-key

OPENAI_API_KEY=...

ANTHROPIC_API_KEY=...

GROQ_API_KEY=...

OLLAMA_CLOUD_API_BASE=https://<host>/v1

OLLAMA_CLOUD_API_KEY=...

A few things that matter more than people expect:

• 
  LITELLM_MASTER_KEY becomes the authentication layer between Open WebUI and LiteLLM


• These values should never be committed into Git


• Weak keys become a real security problem once remote access exists

Even if this starts as a personal setup, treat the environment config like production from day one.

Wiring Docker Compose

The goal here is making sure the containers can talk to each other. Most deployment failures come from small config mismatches rather than Docker itself.

Your Docker-compose.yml should point Open WebUI directly at LiteLLM:

OPENAI_API_BASE_URL=http://litellm:4000/v1

OPENAI_API_KEY=${LITELLM_MASTER_KEY}

This tells Open WebUI where the gateway lives and which key to use.

LiteLLM should mount the configuration file correctly:

./litellm-config.yml:/app/config.yaml

⚠️ That filename matters more than it looks. A typo here can cause Docker to create a directory instead of mounting the file — which leads to confusing startup errors later.

Configuring LiteLLM

Inside litellm-config.yml, LiteLLM defines model aliases, provider routing, gateway behavior, and authentication settings.

The most important section is the master key:

general_settings:

  master_key: os.environ/LITELLM_MASTER_KEY

This keeps secrets outside the YAML file and makes credential rotation easier later.

Inside model_list, make sure provider model IDs are current. Model names change more frequently than most people expect — especially across Groq and newer OpenAI releases.

Starting the Stack

Once your config looks right, start everything:

docker compose up -d --force-recreate

The initial startup may take a minute while Docker pulls images, initializes PostgreSQL, and creates container state.

Verify container health:

docker ps --format 'table {{.Names}}\t{{.Status}}\t{{.Ports}}'

You should see open-webui, litellm, and litellm-db all running.

If a container exits immediately, check its logs before moving forward:

docker logs <container-name>

Validating the Gateway

Before touching Open WebUI, validate LiteLLM first. The /v1/models endpoint confirms authentication works, providers loaded correctly, and model routing initialized.

set -a && source .env && \

curl -s http://localhost:4000/v1/models \

  -H "Authorization: Bearer $LITELLM_MASTER_KEY"

For readable output:

set -a && source .env && \

curl -s http://localhost:4000/v1/models \

  -H "Authorization: Bearer $LITELLM_MASTER_KEY" \

  | python3 -m json.tool | head -n 80

If this endpoint fails, Open WebUI will almost certainly fail too — so resolve gateway issues first.

Verifying Open WebUI

Once LiteLLM responds correctly, open the interface:

http://localhost:3000

You should be able to create chats, select models, and send prompts normally.

If the model dropdown is empty, LiteLLM authentication is usually the cause — mismatched master keys, stale model IDs, or invalid provider credentials.

Keeping Provider Models Current

This catches a lot of people off guard: provider model identifiers change more often than you'd think. A deployment that worked perfectly a few months ago can break because a provider deprecated a model name.

Checking Local Ollama Models

ollama list

Checking Groq Models

set -a && source .env && \

curl -s https://api.groq.com/openai/v1/models \

  -H "Authorization: Bearer $GROQ_API_KEY" \

  -H "Content-Type: application/json"

After updating model IDs in litellm-config.yml, recreate the stack:

docker compose up -d --force-recreate

Secure Remote Access with Cloudflare Tunnel

At this point, the stack only exists locally. The next step is exposing Open WebUI to the internet — without opening inbound ports, exposing your home IP, or managing reverse proxies manually.

Cloudflare Tunnel creates an outbound encrypted connection from your machine to Cloudflare's edge. You get:

• Automatic HTTPS


• Hidden origin infrastructure


• Cloudflare proxy protection


• Simple DNS management

Move DNS to Cloudflare

1. Add your domain to Cloudflare


2. Update nameservers at your registrar


3. Wait for propagation

Authenticate cloudflared

cloudflared tunnel login

This opens a browser window for authorization.

Create the Tunnel

cloudflared tunnel create openwebui

Cloudflare generates a tunnel UUID and a credentials JSON file.

Route a Subdomain

Assuming your domain is chat.yourdomain.tech:

cloudflared tunnel route dns openwebui chat.yourdomain.tech

Create the Tunnel Configuration

Create ~/.cloudflared/config.yml:

tunnel: openwebui

credentials-file: ~/.cloudflared/<tunnel-uuid>.json



ingress:

  - hostname: chat.yourdomain.tech

    service: http://localhost:3000

  - service: http_status:404

Replace <tunnel-uuid> with the generated filename.

Run the Tunnel

cloudflared tunnel run openwebui

For persistent startup on macOS:

cloudflared service install

cloudflared service start

Running the tunnel as a background service is significantly more reliable than keeping it in a terminal session.

Verifying Remote Access

Quick DNS and connectivity check:

dig +short chat.yourdomain.tech

curl -I https://chat.yourdomain.tech

Always use HTTPS for remote access. Cloudflare Tunnel is designed around secure proxied traffic.

Operational Health Checks

Once the stack is stable, this single command gives you a quick overview of everything:

set -a && source .env && \

echo "== Docker services ==" && \

docker ps --format 'table {{.Names}}\t{{.Status}}\t{{.Ports}}' && \

echo "\n== Local Ollama models ==" && \

ollama list && \

echo "\n== Groq model count ==" && \

curl -s https://api.groq.com/openai/v1/models \

  -H "Authorization: Bearer $GROQ_API_KEY" \

  -H "Content-Type: application/json" \

  | python3 -c 'import sys,json; d=json.load(sys.stdin); print(len(d.get("data", [])))' && \

echo "\n== LiteLLM models ==" && \

curl -s http://localhost:4000/v1/models \

  -H "Authorization: Bearer $LITELLM_MASTER_KEY"

Even for personal deployments, having this kind of visibility saves a lot of debugging time.

Troubleshooting

Stable deployments drift. Provider APIs change, Docker mounts break, credentials expire, model IDs get deprecated. Here are the most common failure patterns.

Open WebUI Loads but Models Are Missing

Empty dropdowns, missing providers, or authentication errors in LiteLLM logs.

docker logs --tail 200 litellm

Verify model visibility directly:

set -a && source .env && \

curl -s http://localhost:4000/v1/models \

  -H "Authorization: Bearer $LITELLM_MASTER_KEY"

Typical fixes:

• Verify OPENAI_API_KEY=${LITELLM_MASTER_KEY}
  


• Confirm master_key uses the environment variable


• Recreate containers:
  

docker compose up -d --force-recreate

docker compose restart open-webui

LiteLLM Fails with IsADirectoryError

Docker accidentally created a directory instead of mounting the YAML file.

ls -la ./litellm-config.yml ./litellm-config.yaml

grep -n "litellm-config" Docker-compose.yml

Correct mount:

./litellm-config.yml:/app/config.yaml

Then recreate:

docker compose up -d --force-recreate litellm

Works Locally but Not Through Cloudflare

If local access works but the public hostname fails, focus on the tunnel:

cloudflared tunnel list

cloudflared tunnel info openwebui

cat ~/.cloudflared/config.yml

dig +short chat.yourdomain.tech

curl -I https://chat.yourdomain.tech

Most remote-access failures come from inactive tunnel connectors, incorrect ingress targets, missing proxied DNS records, or running cloudflared in a temporary terminal session.

Models Appear but Generation Fails

If /v1/models works but prompts fail — provider credentials may be invalid, quotas exhausted, or model IDs no longer exist.

set -a && source .env && \

env | grep -E '^(OPENAI_API_KEY|GROQ_API_KEY|ANTHROPIC_API_KEY|LITELLM_MASTER_KEY)=' \

  | sed 's/=.*/=<set>/'

Then inspect LiteLLM logs:

docker logs --tail 300 litellm

Refreshing provider model IDs solves this surprisingly often.

Security Recommendations

Once remote access exists, basic hardening matters:

• Use a strong LITELLM_MASTER_KEY
  


• Don't expose LiteLLM directly to the internet


• Rotate provider API keys periodically


• Keep CORS rules restrictive

For private or team usage, Cloudflare Access adds identity-aware access control in front of Open WebUI — worth enabling.

Capture a Known-Good Baseline

Once things are stable, save:

• 
  docker ps output


• 
  /v1/models output


• Active model aliases


• Tunnel status:
  

cloudflared tunnel info openwebui

When something breaks later, comparing against a working snapshot is almost always faster than debugging from scratch.

Try It Yourself

The full working implementation — Docker Compose, LiteLLM config, environment setup — is all here:

🔗 .

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