---
title: DeepChat
description: Connect DeepChat to Half Off Dev with one OpenAI-compatible provider and use Claude, GPT and Gemini models at 50% of the official price.
---

DeepChat is an open-source desktop chat app that can hold several model providers at once. Register Half Off Dev as an OpenAI-compatible provider and one key gives it Claude, GPT and Gemini, all billed at half the list price. Create an [API key](/app/keys) first.

## Import in one click {#import}

On [API keys](/app/keys), go to **Use in tools** → **DeepChat** and press **Open in DeepChat**. DeepChat (which has to be installed) receives the provider with your key. The key is pre-filled right after you create it; for an existing key, paste it in full, because only its hash is stored.

## Manual setup {#manual-setup}

In DeepChat's provider settings, add one with:

| Field | Value |
| --- | --- |
| Provider type | OpenAI-compatible (or "New API") |
| API host | `https://halfoff.dev` |
| API key | your `ho-...` key |

Enter the host without `/v1`; DeepChat appends it. Next, add the model ids you want to chat with, such as `gpt-6.1-sol`, `gemini-3.1-pro` or `claude-sonnet-5.5`. Every id is on the [model list](/models).

## Fixing errors {#troubleshooting}

| What you see | What to do |
| --- | --- |
| `401` `Invalid or revoked API key` | The key was mistyped, cut short or revoked. Paste it again or make a new one. |
| `404` `Model '...' is not available` | That id doesn't exist. Copy one from `GET /v1/models` or the [model list](/models). |
| `404` with `/v1/v1/` in the path | The API host ends in `/v1`. Change it to `https://halfoff.dev`. |
| `404` `Unknown endpoint` | DeepChat is calling an API Half Off Dev doesn't serve, such as embeddings. Keep Half Off Dev for chat and set another provider for that feature. |
| `402` | The balance is empty or the key has hit its spend cap. See [Billing](/docs/account/billing). |

Any other status is explained in [Errors](/docs/api/errors).