# Introduction

https://modelportal.ai/docs/introduction

This platform relays large-model APIs: one account and one key let you call the models in the catalog over OpenAI-, Anthropic- and Gemini-compatible protocols. The same model often has offers from several providers; the platform picks one by published rules and charges your prepaid balance for actual usage.

## How it differs from calling vendors directly

| | Vendor APIs | This platform |
| --- | --- | --- |
| Setup | One account, key and SDK config per vendor | One key, three protocols; change the base URL |
| Providers | The vendor only | Several offers per model, with different prices, data policies and regions |
| Selection | None | The cheapest eligible endpoint by default, or choose with the [`provider` parameter](/docs/provider-routing) |
| Payment | Top up each vendor | One prepaid balance; failed calls are free |

## The model you request is the model you get

The platform never quietly swaps in another model when yours is unavailable. How it chooses among the endpoints of the same model is described in [Default routing](/docs/default-routing).

## Next steps

- Make your first call with the [Quick start](/docs/quick-start).
- Use an existing tool: see the [Integration guides](/docs/integrations).
- Look up fields and error codes in the [API reference](/docs/api-overview).