---
title: "Migration: Custom Gateway to LiteLLM Proxy Server"
description: "Documentation: Migration: Custom Gateway to LiteLLM Proxy Server"
type: reference
tags: [infra, gateway, litellm, proxy, postgresql, prisma]
timestamp: 2026-07-06
---

# Migration: Custom Gateway to LiteLLM Proxy Server

Migration journey from custom FastAPI gateway to LiteLLM Proxy Server as the main app.

## Timeline

### Phase 1: Custom FastAPI (Jun 2026)
Original gateway in `gateway.py`:
- FastAPI app with manual Tier x Effort routing
- `router.py` (304L) — `(Tier, Effort) → Backend` table
- `handlers/messages.py` — manual HTTP forwarding
- `services/forwarding.py` + `services/fallback.py` — custom proxy
- `core/translation.py` — manual Anthropic to OpenAI translation
- MiMo provider registered via monkey-patch in `ProviderConfigManager`

### Phase 2: LiteLLM Router as Library
- `litellm_router.py` — singleton loading `model_list` from YAML
- `router.acompletion()` replaces manual forwarding
- Hooks registered in `hooks/pipeline.py` (pre_call, post_call)
- Still a separate FastAPI app using LiteLLM as a library

### Phase 3: Proxy Server as Main App (Jul 2026)
- `app = litellm.proxy.proxy_server.app` — the proxy IS the gateway
- 65+ native routes: `/v1/messages`, `/v1/models`, `/health`, `/ui`, `/key/*`, `/user/*`, `/spend/*`
- Custom routes added: voice WS, MCP, search, API handlers
- ~2400 lines of dead code deleted
- Functional admin UI with PostgreSQL

## Critical Discoveries

### CONFIG_FILE_PATH
The proxy reads `CONFIG_FILE_PATH` at startup, NOT `LITELLM_CONFIG_PATH`.
This was the bug that caused "Model list not initialized" for hours.

```python
# proxy_server.py, linha ~786:
env_config_yaml = get_secret_str("CONFIG_FILE_PATH")
if env_config_yaml is not None and os.path.isfile(env_config_yaml):
    llm_router, llm_model_list, general_settings = await proxy_config.load_config(
        router=llm_router, config_file_path=env_config_yaml
    )
```

### Prisma + PostgreSQL
- LiteLLM's schema.prisma uses `provider = "postgresql"` — SQLite doesn't work
- `prisma generate` needs to run with the `litellm_proxy_extras` schema
- `libatomic1` required in Dockerfile (Node.js binaries)
- Migrations: `prisma migrate deploy` creates 71 tables

### Model list in YAML vs model_info
- `model_list` in config YAML defines the models
- `model_info` in each entry defines capabilities (supports_vision, supports_function_calling, supports_1m)
- Proxy serves `/v1/models` in OpenAI format; middleware translates to Anthropic
- Capabilities derived from `model_info` + tier (haiku→low/med, sonnet→+high, opus→all)

### Admin UI
- Served at `/ui` by the proxy
- Login: `UI_USERNAME` / `UI_PASSWORD` from .env
- Internal routes (`/v2/model/info`, `/model/cost_map/source`, `/key/list`, `/spend/logs/ui`)
- `allowed_routes` is an Enterprise feature — remove to avoid blocking internal routes

## MiMo Provider

Registered BEFORE the proxy app import:
```python
from providers.mimo import register_mimo_provider
register_mimo_provider()  # patch ProviderConfigManager
import litellm.proxy.proxy_server
app = litellm.proxy.proxy_server.app
```

`MiMoAnthropicMessagesConfig`:
- Uses `x-api-key` header (not `Authorization: Bearer`)
- API base: `https://token-plan-sgp.xiaomimimo.com/anthropic`
- Strips `[1m]` from model name before sending
- Full URL: `.../anthropic/v1/messages`

DeepSeek Provider:
- Uses `deepseek/deepseek-v4-pro` (not `deepseek/anthropic/`)
- The `/anthropic/` prefix in model name was rejected by the API
- API base: `https://api.deepseek.com/anthropic`

## References
- [[fitalabs-gateway-1p-jornada]] — overview
- [[fitalabs-gateway-modelos]] — model configuration
- [[fitalabs-gateway-modelos]] — original routing table