Gateway API

A single OpenAI-compatible endpoint that routes to 500+ models across 60+ providers. Drop it in wherever you already use the OpenAI SDK — no other changes required.

Base URL

https://getmegabrain.com/api/gateway

Authentication

All requests must include your API key as a Bearer token in the Authorization header. You can find your key on the Profile page after signing in.

curl https://getmegabrain.com/api/gateway/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "gpt-4o-mini", "messages": [{"role": "user", "content": "Hello"}]}'

Free models can be used without authentication, subject to rate limits.

Chat Completions

Fully compatible with the OpenAI Chat Completions API. Both streaming and non-streaming modes are supported.

POSThttps://getmegabrain.com/api/gateway/chat/completions

POSThttps://getmegabrain.com/api/gateway/v1/chat/completions

Example — non-streaming

curl https://getmegabrain.com/api/gateway/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-3-5-sonnet",
    "messages": [
      {"role": "system", "content": "You are a helpful assistant."},
      {"role": "user", "content": "What is the capital of France?"}
    ]
  }'

Example — streaming

curl https://getmegabrain.com/api/gateway/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-3-5-sonnet",
    "stream": true,
    "messages": [{"role": "user", "content": "Tell me a joke"}]
  }'

Example — OpenAI SDK

import OpenAI from "openai";

const client = new OpenAI({
  apiKey: "YOUR_API_KEY",
  baseURL: "https://getmegabrain.com/api/gateway",
});

const response = await client.chat.completions.create({
  model: "anthropic/claude-3-5-sonnet",
  messages: [{ role: "user", content: "Hello!" }],
});

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

Auto Model

Set model to one of the Auto Model IDs to let the Gateway choose the best model for each request based on your selected tier.

Model ID	Description
auto-balanced	Automatically selects the best available model
auto-free	Routes only to free models
auto-frontier	Routes to frontier paid models
auto-balanced	Cost-effective routing across capable paid models

Request body

Parameter	Type	Required	Description
model	string	Yes	Model ID (e.g. gpt-4o, anthropic/claude-3-5-sonnet, auto-balanced)
messages	array	Yes	Array of message objects with role and content
stream	boolean	No	Enable server-sent event streaming (default: false)
temperature	number	No	Sampling temperature 0–2
max_tokens	integer	No	Maximum tokens to generate
tools	array	No	Function/tool definitions for tool use

Embeddings

Generate vector embeddings from text. Compatible with the OpenAI Embeddings API.

POSThttps://getmegabrain.com/api/gateway/embeddings

curl https://getmegabrain.com/api/gateway/embeddings \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "text-embedding-3-small",
    "input": "The quick brown fox"
  }'

import OpenAI from "openai";

const client = new OpenAI({
  apiKey: "YOUR_API_KEY",
  baseURL: "https://getmegabrain.com/api/gateway",
});

const result = await client.embeddings.create({
  model: "text-embedding-3-small",
  input: "The quick brown fox",
});

console.log(result.data[0].embedding);

Audio Transcriptions

Transcribe audio files to text. Compatible with the OpenAI Audio Transcriptions API.

POSThttps://getmegabrain.com/api/gateway/audio/transcriptions

POSThttps://getmegabrain.com/api/gateway/v1/audio/transcriptions

curl https://getmegabrain.com/api/gateway/audio/transcriptions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F model="whisper-1" \
  -F file="@audio.mp3"

List Models

Retrieve the list of models available through the Gateway. The response follows the OpenAI models format.

GEThttps://getmegabrain.com/api/gateway/models

GEThttps://getmegabrain.com/api/gateway/embedding-models

GEThttps://getmegabrain.com/api/gateway/transcription-models

GEThttps://getmegabrain.com/api/gateway/providers

curl https://getmegabrain.com/api/gateway/models \
  -H "Authorization: Bearer YOUR_API_KEY"

{
  "data": [
    {
      "id": "anthropic/claude-3-5-sonnet",
      "name": "Claude 3.5 Sonnet",
      "context_length": 200000,
      "pricing": { "prompt": "0.000003", "completion": "0.000015" }
    },
    ...
  ]
}

Errors

The Gateway uses standard HTTP status codes. Error responses include an error field and an error_type machine-readable code.

Status	error_type	Description
400	invalid_request	Malformed JSON or missing required fields
400	missing_client_ip	Unable to determine client IP address
401	authentication_required	Missing or invalid API key
401	paid_model_auth_required	Paid model requires authentication
401	promotion_limit_reached	Anonymous free-model limit reached — sign up to continue
429	rate_limit_exceeded	Free model rate limit exceeded
503	temporarily_unavailable	Model or provider is temporarily unavailable

{
  "error": {
    "code": "PAID_MODEL_AUTH_REQUIRED",
    "message": "You need to sign in to use this model."
  },
  "error_type": "paid_model_auth_required"
}

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