exchangerate.devAdd exchangerate.dev as a custom MCP connector so ChatGPT can request currency rates and conversions. The hosted server works without an API key. Keyless and Free rates are 15 minutes late; paid plans get live rates.
What you need before connecting
ChatGPT supports custom MCP connectors through developer mode, which you switch on in ChatGPT's settings. Check OpenAI's current help pages for which plans can add custom connectors, because availability changes.
Workspace rules can also require an admin or owner to allow custom connectors first. ChatGPT requires a server reachable over HTTPS and supports Streamable HTTP, which the hosted exchangerate.dev server uses.
These steps follow OpenAI's documented flow.
Add the server
In ChatGPT's settings, enable developer mode, add a custom MCP connector, enter a name and the server URL from the snippet, and choose none for authentication.
Keep the trailing slash in the URL. The hosted server answers tool discovery and tool calls without a key. This setup uses the shared keyless pool, with limits of 10 requests a minute and 100 an hour per IP.
https://api.exchangerate.dev/v1/mcp/Ask for a rate or conversion
Ask ChatGPT, "How many Japanese yen is 100 euros right now?" and have it quote the time returned with the rate.
The convert tool answers that question with the rate and converted amount. It also flags a rate derived through USD.
For a historical request, ask "What was USD to IDR on 1 September?" The get_range tool reads rates over a date range; get_rate reads the latest rate for a base and quote currency. Ask "Which currencies can you look up?" to use list_currencies.
What ChatGPT can read
The server has nine tools. Beyond the rate, conversion, history and currency tools, get_usd_index returns a USD index from an independent calculation, and search_docs searches the documentation.
list_official_rate_tables lists government-published rate tables, and get_official_rate reads government-published rates. The start_checkout tool opens a plan checkout only after you confirm.
Answers carry source, market_session and data_updated_at, plus a notice that rates are indicative and unsuitable for settlement. Ask ChatGPT to quote the returned time when it reads the numbers. These rates are not for settlement or trading, and the keyless connector does not return paid-plan live rates.
If the connector fails
Check the server URL against the snippet, including its trailing slash, if the connector cannot connect.
A wrong URL is the usual cause of a connection failure. An HTTP 429 means the shared keyless pool or minute limit has been reached. Wait for the retry time before another request.
After the server's tools change, refresh the connector so ChatGPT has the updated tool list.