Use Parallel AI as an OpenAI API Drop-In Replacement

Overview

Parallel AI’s POST /api/v0/chat/completions endpoint is 100% compatible with OpenAI’s Chat Completions API spec. To migrate an existing integration, you only need to change the base_url in your client — no other code changes are required.

This means any library, tool, or service built for the OpenAI API works out of the box with Parallel AI. Swap the base URL and your API key, and you’re done.

Quick Start

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.parallellabs.app/api/v0"
)

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "What can Parallel AI help me with?"}
    ]
)

print(response.choices[0].message.content)

import OpenAI from 'openai';

const client = new OpenAI({
  apiKey: 'YOUR_API_KEY',
  baseURL: 'https://api.parallellabs.app/api/v0',
});

const response = await client.chat.completions.create({
  model: 'gpt-4o',
  messages: [
    { role: 'system', content: 'You are a helpful assistant.' },
    { role: 'user', content: 'What can Parallel AI help me with?' },
  ],
});

console.log(response.choices[0].message.content);

curl -X POST "https://api.parallellabs.app/api/v0/chat/completions" \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4o",
    "messages": [
      { "role": "system", "content": "You are a helpful assistant." },
      { "role": "user", "content": "What can Parallel AI help me with?" }
    ]
  }'

Supported Parameters

The following request parameters are fully supported:

Parameter	Type	Description
`model`	string	The model to use for completion
`messages`	array	Array of message objects with `role` and `content`
`temperature`	number	Sampling temperature between 0 and 2
`max_tokens`	integer	Maximum number of tokens to generate
`stream`	boolean	Stream the response using Server-Sent Events (SSE)
`top_p`	number	Nucleus sampling probability mass
`frequency_penalty`	number	Penalise repeated tokens based on frequency
`presence_penalty`	number	Penalise tokens based on presence in prior text
`tools`	array	List of tools the model may call
`tool_choice`	string or object	Controls which tool (if any) the model uses
`response_format`	object	Set to `{ "type": "json_object" }` to force JSON output
`stop`	string or array	Up to 4 sequences where the API will stop generating
`seed`	integer	Seed for deterministic sampling
`logit_bias`	object	Modify the likelihood of specific tokens appearing
`user`	string	A unique identifier for the end user

Streaming

Set stream: true to receive a streaming response using Server-Sent Events (SSE), identical to OpenAI’s streaming format.

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://api.parallellabs.app/api/v0"
)

stream = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Tell me about AI for business."}],
    stream=True,
)

for chunk in stream:
    if chunk.choices[0].delta.content is not None:
        print(chunk.choices[0].delta.content, end="", flush=True)

import OpenAI from 'openai';

const client = new OpenAI({
  apiKey: 'YOUR_API_KEY',
  baseURL: 'https://api.parallellabs.app/api/v0',
});

const stream = await client.chat.completions.create({
  model: 'gpt-4o',
  messages: [{ role: 'user', content: 'Tell me about AI for business.' }],
  stream: true,
});

for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? '');
}

Each streamed chunk follows the standard OpenAI SSE format with data: prefixed JSON objects, ending with data: [DONE].

Learn More

Chat Features Overview — explore Parallel AI’s chat capabilities
Chat Completions API Reference — full endpoint documentation

Get Started

Core Features

Integrations

Platform

Use Parallel AI as an OpenAI API Drop-In Replacement

Overview

Quick Start

Supported Parameters

Streaming

Learn More

​Overview

​Quick Start

​Supported Parameters

​Streaming

​Learn More

Overview

Quick Start

Supported Parameters

Streaming

Learn More