Migrate Litellm To Portkey

Migrate from LiteLLM to Portkey

Step-by-step guide for migrating Python applications from LiteLLM to the Portkey AI Gateway SDK. Portkey uses an OpenAI-compatible client interface, so most code changes are structural (client instantiation and config) rather than call-signature changes.

Additional References:

• Detailed Migration Patterns - Every LiteLLM pattern with before/after code
• Proxy & Config Migration - LiteLLM Proxy → Portkey gateway migration

Pre-Migration Checklist

1. Get a Portkey API key at app.portkey.ai/api-keys
2. Set up AI Providers in the Model Catalog — connect your LLM providers (OpenAI, Anthropic, Azure, Bedrock, etc.) and note each provider's slug (e.g., openai-prod, anthropic-main)
3. Swap the package:

   pip uninstall litellm
   pip install portkey-ai
   

4. Set environment variables:

   export PORTKEY_API_KEY="your-portkey-api-key"
   # Provider keys are now stored securely in the Model Catalog
   # You no longer need OPENAI_API_KEY, ANTHROPIC_API_KEY, etc. in your env
   

5. (Optional) Verify connectivity with the Portkey CLI:

   npx portkey verify
   

Quick Migration Map

Core Migrations

1. Basic Completion

LiteLLM:

from litellm import completion
import os

os.environ["OPENAI_API_KEY"] = "sk-..."

response = completion(
    model="openai/gpt-4o",
    messages=[{"role": "user", "content": "Hello!"}]
)
print(response.choices[0].message.content)

Portkey:

import os
from portkey_ai import Portkey

client = Portkey(
    api_key=os.environ["PORTKEY_API_KEY"]
)

response = client.chat.completions.create(
    model="@openai-prod/gpt-4o",
    messages=[{"role": "user", "content": "Hello!"}]
)
print(response.choices[0].message.content)

Key differences:

• Stateless function → stateful client object
• Model format changes from "openai/gpt-4o" to "@provider-slug/gpt-4o" where the provider slug comes from your Model Catalog
• Provider API keys no longer needed in env — credentials are stored in the Model Catalog

2. Streaming

LiteLLM:

for chunk in completion(
    model="openai/gpt-4o",
    messages=[{"role": "user", "content": "Write a poem"}],
    stream=True,
):
    print(chunk.choices[0].delta.content or "", end="")

Portkey:

stream = client.chat.completions.create(
    model="@openai-prod/gpt-4o",
    messages=[{"role": "user", "content": "Write a poem"}],
    stream=True
)
for chunk in stream:
    if chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)

3. Async

LiteLLM:

import litellm
response = await litellm.acompletion(
    model="openai/gpt-4o",
    messages=[{"role": "user", "content": "Hello!"}]
)

Portkey:

from portkey_ai import AsyncPortkey

client = AsyncPortkey(
    api_key=os.environ["PORTKEY_API_KEY"]
)
response = await client.chat.completions.create(
    model="@openai-prod/gpt-4o",
    messages=[{"role": "user", "content": "Hello!"}]
)

4. Fallbacks

LiteLLM:

response = completion(
    model="openai/gpt-4o",
    messages=messages,
    fallbacks=["anthropic/claude-3-5-sonnet-20241022"]
)

Portkey:

client = Portkey(
    api_key=os.environ["PORTKEY_API_KEY"],
    config={
        "strategy": {"mode": "fallback"},
        "targets": [
            {
                "override_params": {"model": "@openai-prod/gpt-4o"}
            },
            {
                "override_params": {"model": "@anthropic-main/claude-3-5-sonnet-20241022"}
            }
        ]
    }
)
response = client.chat.completions.create(messages=messages)

5. Load Balancing (Router)

LiteLLM:

from litellm import Router

model_list = [
    {
        "model_name": "gpt-3.5-turbo",
        "litellm_params": {
            "model": "azure/chatgpt-v-2",
            "api_key": os.getenv("AZURE_API_KEY"),
            "api_base": os.getenv("AZURE_API_BASE"),
            "rpm": 900
        }
    },
    {
        "model_name": "gpt-3.5-turbo",
        "litellm_params": {
            "model": "openai/gpt-3.5-turbo",
            "api_key": os.getenv("OPENAI_API_KEY"),
            "rpm": 100
        }
    }
]

router = Router(model_list=model_list, routing_strategy="simple-shuffle")
response = await router.acompletion(
    model="gpt-3.5-turbo",
    messages=[{"role": "user", "content": "Hello!"}]
)

Portkey:

client = Portkey(
    api_key=os.environ["PORTKEY_API_KEY"],
    config={
        "strategy": {"mode": "loadbalance"},
        "targets": [
            {
                "override_params": {"model": "@azure-prod/gpt-3.5-turbo"},
                "weight": 0.9
            },
            {
                "override_params": {"model": "@openai-prod/gpt-3.5-turbo"},
                "weight": 0.1
            }
        ]
    }
)
response = client.chat.completions.create(
    messages=[{"role": "user", "content": "Hello!"}]
)

6. Retries

LiteLLM:

response = completion(
    model="openai/gpt-4o",
    messages=messages,
    num_retries=3
)

Portkey:

client = Portkey(
    api_key=os.environ["PORTKEY_API_KEY"],
    config={
        "retry": {"attempts": 3, "on_status_codes": [429, 500, 502, 503, 504]}
    }
)
response = client.chat.completions.create(
    model="@openai-prod/gpt-4o",
    messages=messages
)

7. Caching

LiteLLM:

import litellm
from litellm.caching.caching import Cache

litellm.cache = Cache(type="redis", host="localhost", port=6379)

response = completion(model="openai/gpt-4o", messages=messages, caching=True)

Portkey: (no infrastructure to manage — caching is built-in)

client = Portkey(
    api_key=os.environ["PORTKEY_API_KEY"],
    config={
        "cache": {"mode": "semantic", "max_age": 3600}
    }
)
response = client.chat.completions.create(
    model="@openai-prod/gpt-4o",
    messages=messages
)

8. Observability

LiteLLM:

import litellm
litellm.success_callback = ["langfuse"]
litellm.failure_callback = ["langfuse"]

Portkey: (built-in — every request is logged automatically)

client = Portkey(
    api_key=os.environ["PORTKEY_API_KEY"],
    trace_id="session-123",
    metadata={
        "user_id": "user-456",
        "environment": "production"
    }
)

View logs, traces, costs, and latency at app.portkey.ai. No third-party callback integration needed.

Model Naming

LiteLLM uses provider/model format. Portkey uses @provider-slug/model where the provider slug comes from your Model Catalog:

The @slug prefix maps to an AI Provider in your Model Catalog. You control which models are available under each provider.

Error Handling

LiteLLM:

import litellm
try:
    response = completion(model="openai/gpt-4o", messages=messages)
except litellm.AuthenticationError:
    print("Bad API key")
except litellm.RateLimitError:
    print("Rate limited")

Portkey:

try:
    response = client.chat.completions.create(
        model="@openai-prod/gpt-4o", messages=messages
    )
except Exception as e:
    status = getattr(e, 'status_code', None)
    if status == 401:
        print("Bad API key")
    elif status == 429:
        print("Rate limited")

AI Coding Agent Migrations

Claude Code

If Claude Code is routed through a LiteLLM Proxy (via ANTHROPIC_BASE_URL), the fastest migration is:

npx portkey setup

This replaces the LiteLLM Proxy env vars (ANTHROPIC_BASE_URL, ANTHROPIC_API_KEY) with Portkey equivalents. See Proxy Migration — Claude Code section for manual setup, Bedrock/Vertex model mappings, and Config-based routing.

OpenAI Codex CLI

If Codex CLI is routed through a LiteLLM Proxy (via openai_base_url or OPENAI_BASE_URL), update ~/.codex/config.json to point at Portkey with a portkey provider and model: "@provider-slug/model" format. See Proxy Migration — Codex section for step-by-step setup.

Zero-Change Path: Keep LiteLLM, Route Through Portkey

If you want Portkey's observability and reliability without rewriting any code, you can keep using litellm.completion() and just point it at Portkey's gateway:

from litellm import completion

response = completion(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Hello!"}],
    api_base="https://api.portkey.ai/v1",
    api_key=os.environ["PORTKEY_API_KEY"],
    extra_headers={"x-portkey-provider": "@openai-prod"}
)

This gives you Portkey logging, caching, and guardrails immediately — then you can migrate call-by-call to the Portkey SDK at your own pace.

OpenAI Client Approach (Minimal Changes)

If your codebase uses the OpenAI SDK to talk to LiteLLM's proxy, you can switch to Portkey by only changing base_url and adding headers — no import changes required:

import openai
from portkey_ai import PORTKEY_GATEWAY_URL, createHeaders

client = openai.OpenAI(
    api_key="not-used",
    base_url=PORTKEY_GATEWAY_URL,  # https://api.portkey.ai/v1
    default_headers=createHeaders(
        api_key="your-portkey-api-key"
    )
)

response = client.chat.completions.create(
    model="@openai-prod/gpt-4o",
    messages=[{"role": "user", "content": "Hello!"}]
)

This also works in TypeScript/JavaScript:

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.portkey.ai/v1",
  apiKey: process.env.PORTKEY_API_KEY,
  defaultHeaders: { "x-portkey-provider": "@openai-prod" }
});

const response = await client.chat.completions.create({
  model: "gpt-4o",
  messages: [{ role: "user", content: "Hello!" }]
});

Quick Verification with cURL

Before changing any code, test the gateway connection:

curl -s https://api.portkey.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "x-portkey-api-key: $PORTKEY_API_KEY" \
  -H "x-portkey-provider: @openai-prod" \
  -d '{
    "model": "gpt-4o",
    "max_tokens": 5,
    "messages": [{"role": "user", "content": "Say ok"}]
  }'

Routing via Headers

Portkey supports two routing modes, set via headers:

With the @provider-slug/model format in the model parameter, you typically don't need to set these headers explicitly.

Migration Workflow

1. Verify — Test connectivity before touching code:

   npx portkey verify
   

2. Audit — Grep your codebase for LiteLLM usage:

   grep -rn "from litellm\|import litellm\|litellm\." --include="*.py"
   

3. Quick win — Point existing LiteLLM calls at Portkey with api_base (see Zero-Change Path)
4. Map — For each usage, find the Portkey equivalent using the table above or MIGRATION_PATTERNS.md
5. Replace — Swap imports, instantiate a Portkey client, and update call sites
6. Configure — Move routing/fallback/cache logic from code into Portkey config dicts (or dashboard Config IDs)
7. Test — Run your test suite; response formats are identical (OpenAI-compatible)
8. Clean up — Remove litellm from requirements, remove provider API key env vars

Resources

• Portkey Docs: docs.portkey.ai
• Dashboard: app.portkey.ai
• Python SDK: github.com/portkey-ai/portkey-python-sdk
• Discord: portkey.ai/discord