Your storefront assistant, product and review summaries, and AI search all call OpenAI. Those calls run on your own OpenAI account. Connect a key and the features turn on; OpenAI bills you directly for the usage. Mercemur funds no model calls and adds no per-reply fee on top. Your subscription covers the platform, not the model usage, which is why the AI agent is not one of the metered resources on your bill.
Bringing your own key is included from the Growth plan up. The Free plan does not include the AI features a key would fund.

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Connect a key

  1. Create an API key in your OpenAI dashboard, under API keys.
  2. In Mercemur, go to Settings > AI provider key.
  3. Paste the key and save.
We check the key against OpenAI before storing anything, so a key that is refused leaves nothing behind. You never see a connected key that was not actually accepted.
A restricted key is enough, and is what we recommend. It needs write access to model capabilities, and nothing else. It does not need permission to list models, read your usage, or manage your account.

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What a restricted key needs

The check embeds a single token with text-embedding-3-small, which is the same model and the same permission your store’s real calls use. That is deliberate: a key that passes the check is a key that can do the work, rather than one that merely exists. If your key is valid but too narrow, you are told to widen the key you have rather than to replace it. Those are different fixes and the screen keeps them apart.

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The model does not change

Your key pays for the calls. It does not choose the model. Embeddings are pinned to one model platform-side because every store’s vectors share a single collection at a fixed size. A merchant-chosen embedding model would either be refused on write or would land vectors that do not sit correctly beside everyone else’s. Connecting or disconnecting a key therefore never invalidates what your store has already learned, and nothing needs re-indexing either way.

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If your key stops working

A key can stop working after it was proven good: it gets revoked, the project loses access to the model, or the account runs out of credit. When that happens your store’s AI features stop. They do not quietly fall back to a Mercemur key.
The fallback is deliberately absent. If a broken key silently moved your traffic onto a Mercemur key, you would be billed for usage you believed you were paying for yourself, and you would not find out until an invoice arrived.
The settings page separates two states that look alike and need different responses: Use Check key on the settings page to re-run the check against OpenAI at any time, so you find out there rather than from an assistant that has gone quiet.

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Disconnect

Disconnecting turns your store’s AI features off. The storefront assistant, AI summaries and AI search stop working until you connect another key. There is no Mercemur-funded fallback to return to.
OpenAI stops charging your account the moment the key is disconnected.

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Things worth knowing

  • The key is never shown again. After you save it, the settings page shows only the last four characters, so you can tell which of your keys is connected.
  • Every change is recorded. Saving, checking, and disconnecting a key each write an audit entry naming who did it. The entries never contain the key itself.
  • This screen is rate limited to 20 requests a minute per store.
  • OpenAI is the only provider today. The storage and the settings screen were built to take more than one, so adding another does not change what you have set up here.