Functions Usage
Portkey supports the OpenAI signature to define functions. Pass the tools parameter to models that support function/tool calling.
NodeJS
Python
OpenAI NodeJS
OpenAI Python
cURL
import Portkey from 'portkey-ai';
const portkey = new Portkey({
apiKey: "PORTKEY_API_KEY",
});
async function run() {
const response = await portkey.chat.completions.create({
model: "MODEL_NAME",
messages: [{ role: "user", content: "What's the weather like in Boston today?" }],
tools: [{
type: "function",
function: {
name: "get_current_weather",
description: "Get the current weather in a given location",
parameters: {
type: "object",
properties: {
location: {
type: "string",
description: "The city and state, e.g. San Francisco, CA",
},
unit: { type: "string", enum: ["celsius", "fahrenheit"] },
},
required: ["location"],
},
}
}],
tool_choice: "auto",
});
console.log(response.choices[0].message.tool_calls);
}
run();
from portkey_ai import Portkey
portkey = Portkey(
api_key="PORTKEY_API_KEY",
)
completion = portkey.chat.completions.create(
model="MODEL_NAME",
messages=[{"role": "user", "content": "What's the weather like in Boston today?"}],
tools=[{
"type": "function",
"function": {
"name": "get_current_weather",
"description": "Get the current weather in a given location",
"parameters": {
"type": "object",
"properties": {
"location": {
"type": "string",
"description": "The city and state, e.g. San Francisco, CA",
},
"unit": {"type": "string", "enum": ["celsius", "fahrenheit"]},
},
"required": ["location"],
},
}
}],
tool_choice="auto"
)
print(completion.choices[0].message.tool_calls)
import OpenAI from 'openai';
import { PORTKEY_GATEWAY_URL, createHeaders } from 'portkey-ai'
const openai = new OpenAI({
baseURL: PORTKEY_GATEWAY_URL,
defaultHeaders: createHeaders({
apiKey: "PORTKEY_API_KEY"
})
});
async function run() {
const response = await openai.chat.completions.create({
model: "MODEL_NAME",
messages: [{ role: "user", content: "What's the weather like in Boston today?" }],
tools: [{
type: "function",
function: {
name: "get_current_weather",
description: "Get the current weather in a given location",
parameters: {
type: "object",
properties: {
location: {
type: "string",
description: "The city and state, e.g. San Francisco, CA",
},
unit: { type: "string", enum: ["celsius", "fahrenheit"] },
},
required: ["location"],
},
}
}],
tool_choice: "auto",
});
console.log(response.choices[0].message.tool_calls);
}
run();
from openai import OpenAI
from portkey_ai import PORTKEY_GATEWAY_URL, createHeaders
openai = OpenAI(
base_url=PORTKEY_GATEWAY_URL,
default_headers=createHeaders(
api_key="PORTKEY_API_KEY"
)
)
completion = openai.chat.completions.create(
model="MODEL_NAME",
messages=[{"role": "user", "content": "What's the weather like in Boston today?"}],
tools=[{
"type": "function",
"function": {
"name": "get_current_weather",
"description": "Get the current weather in a given location",
"parameters": {
"type": "object",
"properties": {
"location": {
"type": "string",
"description": "The city and state, e.g. San Francisco, CA",
},
"unit": {"type": "string", "enum": ["celsius", "fahrenheit"]},
},
"required": ["location"],
},
}
}],
tool_choice="auto"
)
print(completion.choices[0].message.tool_calls)
curl "https://api.portkey.ai/v1/chat/completions" \
-H "Content-Type: application/json" \
-H "x-portkey-api-key: $PORTKEY_API_KEY" \
-d '{
"model": "MODEL_NAME",
"messages": [
{
"role": "user",
"content": "What is the weather like in Boston?"
}
],
"tools": [
{
"type": "function",
"function": {
"name": "get_current_weather",
"description": "Get the current weather in a given location",
"parameters": {
"type": "object",
"properties": {
"location": {
"type": "string",
"description": "The city and state, e.g. San Francisco, CA"
},
"unit": {
"type": "string",
"enum": ["celsius", "fahrenheit"]
}
},
"required": ["location"]
}
}
}
],
"tool_choice": "auto"
}'
tool_choice parameter, and Portkey validates your tool definition on the fly, eliminating syntax errors.
Supported Providers and Models
Portkey provides native function calling support across all major AI providers.
If you discover a function-calling capable LLM that isn’t working with Portkey, please let us know on Discord.
Cookbook
See the detailed cookbook on function calling.Last modified on March 16, 2026
