RikkaHub

RikkaHub is an open-source chat app for Android. You can add a provider with an OpenAI-compatible endpoint to it. Set that provider to the exchange. The exchange sets a cap before the first token and charges for measured use.

Before you start

A workspace with a balance and a spend key. See API keys.
RikkaHub installed from rikka-ai.com or Google Play.

1. Add a provider

Open Settings → Providers. Tap the + button at the top of the page. In the Add Provider dialog, keep the provider type OpenAI. Enter a name in Name:

Liquid Inference

2. Set the key and the base URL

Paste your key into API Key:

sk-liquid-...

Replace the value in API Base Url with this URL:

https://router.inference.ai.exchange/v1

The base URL ends in /v1, because RikkaHub adds /chat/completions to it. Keep the default value of API Path. Keep Response API off. Then tap Add.

3. Add the models

Open the new provider and go to the Models tab. RikkaHub reads GET /v1/models from the exchange and shows the names in a list. Open the list with the button that shows the number of models. Select each name that you want, for example:

liquid.auto

To use a name that is not in the list, tap Add New Model and type it in Model ID. To get the current names, see the Market page. See Market data.

RikkaHub sets the abilities of a model from the model ID. It does not know the names of router models or presets. To use tools or a reasoning level with one of these names, edit the model and turn on Tool or Reasoning in Abilities.

4. Set a cap on each request

Open the Advanced Settings tab of the provider. Under Custom Headers, add a header. Set Header Name to:

x-liquid-cap-usd

Set Header Value to the cap in USD:

1.00

RikkaHub sends the header with each request to this provider. The cap limits each request. It does not limit the total charge of a conversation. Auto refuses a request that has no price bound. See Auto Router.

The client on the receipt

The receipt names RikkaHub and its version as the client. You do not need to set anything for this.

Do not set a value in Settings → Preferences → Network → User-Agent. If you set one, the receipt does not name RikkaHub.

Notes

The exchange sets a cap on each request. To limit total spend, set a spending limit on the key. See API keys.
If a model has the Reasoning ability and you select a reasoning level, RikkaHub sends reasoning_effort. The exchange sends a request with a reasoning effort only to an offer that accepts one.
Use a preset for other purchasing rules. See Purchasing rules.

Troubleshooting

Symptom	Cause and fix
`401`	The key is empty, wrong or expired. Paste it again into API Key.
`403`	Check the key's `spend` scope, address restriction and preset rules.
`402`	Add credit to the workspace or check the key's spend limit.
`404`	Keep `/v1` at the end of the base URL, and keep `/chat/completions` as the path.
The model list is empty.	Check the base URL and the key. RikkaHub reads the list with the same key.
`model_not_found`	The model ID is not on the book. Use an exact name from the Market page.
`auto_requires_price_bound`	Add the `x-liquid-cap-usd` header in step 4.
A request is refused for lack of funds.	The workspace balance cannot cover the cap. Add funds on the Credits page.

See Errors for the exchange's error codes and causes.

Next steps

Z Code: a desktop agent with the same kind of provider.
Market data: models and live offers.
API keys: scopes and spending limits.