--- title: "How can I get ChatGPT to look up fund and ETF data by ISIN?" description: "Connect the FundFacts MCP server in ChatGPT's developer mode and ask about any ISIN, with results shown as interactive cards. Or build a custom GPT on the OpenAPI spec, or paste the JSON. Steps for each." canonical: https://fundfactsapi.com/answers/fund-data-for-chatgpt published: 2026-09-12 updated: 2026-10-13 publisher: FundFacts API --- # How can I get ChatGPT to look up fund and ETF data by ISIN? **Short answer:** Connect the FundFacts MCP server. In ChatGPT's developer mode (Plus, Pro, Business, Enterprise and Edu, on the web), add https://fundfactsapi.com/api/mcp under Plugins with Authentication set to OAuth and sign in with your FundFacts account; ChatGPT can then look up, compare and look through funds by ISIN or name, and shows the results as interactive cards. On plans that can create GPTs, build a custom GPT whose Action imports the OpenAPI spec at https://fundfactsapi.com/openapi.json with bearer authentication. For a one-off question, paste the JSON from a single GET /funds/{isin} call into the chat. **Fastest route: the FundFacts MCP server.** About a minute in developer mode, on every FundFacts plan including Free, with seven read-only tools and results shown as interactive cards in the chat. The [MCP server guide](https://fundfactsapi.com/docs/mcp) covers every tool, the sign-in and troubleshooting; the steps for ChatGPT are below. ## Why ChatGPT needs a data source for funds Fund figures live in PDFs and product pages that change monthly. A model answering from memory will quote a TER or a top holding from whenever its training data was collected, without an as-of date. Giving ChatGPT a tool that returns the current published figures fixes both problems: the answer is current and it carries `dataAsOf`. ## Option 1: connect the MCP server ChatGPT adds remote MCP servers in developer mode, available on Plus, Pro, Business, Enterprise and Edu, on the web. Turn it on under **Settings → Security and login → Developer mode**, then open **Plugins** (chatgpt.com/plugins), click **+** and enter: | Setting | Value | |---|---| | Name | FundFacts | | Server URL | `https://fundfactsapi.com/api/mcp` | | Authentication | OAuth | Click **Create** and sign in with your FundFacts account when the consent screen opens. ChatGPT cannot send an API key (the dialog has no header field), so it signs in instead. The connector signs in with your FundFacts account (OAuth 2.1, PKCE): a consent screen opens in the browser, the connection then counts against the same plan and quota as an API key, and it appears in the [dashboard](https://fundfactsapi.com/dashboard), where you can disconnect it at any time. In ChatGPT and in Claude on the web and desktop, tool results also render as cards (fund, comparison, portfolio look-through, overlap, SCPI) next to the answer. No API key goes into the URL; for code and CLIs the `Authorization` header stays the recommended form. The MCP server exposes seven tools, each counted like the REST endpoint it wraps: `get_fund` (ISIN → the full factsheet payload), `search_funds` (name → ISINs, free), `compare_funds` (side-by-side table for several ISINs), `analyze_portfolio` (weighted look-through of a list of positions, Starter and above), `fund_overlap` (shared holdings between funds, Starter and above), `get_scpi` (French SCPI data by name or ISIN) and `search_scpi` (SCPI name → matches, free), plus a `tour` prompt that explains the service on the example fund IE00B4L5Y983, which is not counted. Every tool only reads data. Authentication is either your FundFacts account (OAuth 2.1 with PKCE, the sign-in the claude.ai, Claude Desktop and ChatGPT connectors run) or the same bearer API key as the REST API, sent as an `Authorization` header by editors, CLIs and frameworks. The [MCP server guide](https://fundfactsapi.com/docs/mcp) has the full tool reference, setup for every client and troubleshooting. Then ask in plain language: "What is the TER and top ten of IE00B4L5Y983?", "Compare IE00B4L5Y983 and IE00B3RBWM25", "How much do these two ETFs overlap?". ChatGPT picks the tool, calls it and cites the figures with their as-of date. ## Option 2: a custom GPT with an Action Custom GPTs take an OpenAPI document as an Action, which works on every plan that can create GPTs: 1. Create a GPT, open **Configure → Actions → Create new action**. 2. Choose **Import from URL** and paste `https://fundfactsapi.com/openapi.json`. 3. Authentication: **API Key**, auth type **Bearer**, paste your `ffk_` key. 4. In the instructions, add: "Use getFund for any ISIN the user mentions. Always state data.dataAsOf next to figures. Treat 404 fund_not_found as 'not a covered fund'." The spec describes every endpoint (single fund, batch, search, portfolio look-through, overlap, factsheets, SCPI), so the GPT can answer more than lookups. ## Option 3: paste the JSON For a one-off question, run one call and paste the result: ```bash curl -s https://fundfactsapi.com/api/v1/funds/IE00B4L5Y983 -H "Authorization: Bearer $FUNDFACTS_API_KEY" ``` The payload is a few kilobytes of JSON with self-describing keys (`headlineMetrics.ter`, `topHoldings`, `sector`, `calendarReturns`, `dataAsOf`), so ChatGPT reads it without further explanation. Without a key, `GET https://fundfactsapi.com/api/v1/demo/funds/IE00B4L5Y983` returns the same payload for funds already in the store. ## What to tell the model Whichever route you take, two instructions improve the answers: quote `data.dataAsOf` with every figure, and do not fill gaps. Fields a fund does not disclose come back empty, not missing, and the model should say "not disclosed" rather than estimate. Paid plans include an AI companion kit generated from the live field reference: an `AGENTS.md` with every endpoint, field, rule and a reference client; a Cursor rule; a Claude Code skill; the OpenAPI spec and TypeScript types, with your key baked in or read from an environment variable. Download it from the dashboard; the public edition without a key is at [/llms-full.txt](https://fundfactsapi.com/llms-full.txt). ## FAQ ### Does the connector cost extra? No. Tool calls are counted exactly like REST requests on your plan: one request per fund found. The Free plan's 5 lookups a month are enough to try it; a working assistant usually sits on Starter or Pro. ### Will ChatGPT cite fundfactsapi.com in search answers? ChatGPT search reads this site (the crawlers are allowed in robots.txt and the pages are listed in llms.txt), so answers about fund data APIs may cite it. That is independent of the connector, which is about your own account's data access. ### Do I need a credit card to try it? No. The Free plan is 5 lookups per month with no card; sign up with an e-mail address or Google and the key is shown in the dashboard. ### Which ISINs work? Any share class of a UCITS fund, ETF, money-market fund or open-end fund whose management company publishes a product page, factsheet and KID. Each share class has its own ISIN and is looked up on its own. Stocks, bonds and indices are not funds and return 404 fund_not_found. ## About FundFacts API FundFacts turns any fund or ETF ISIN into one dated factsheet (fees and KID costs, the 1–7 risk indicator, holdings, sector and country exposure, returns) read from the fund house's own documents: as a client-ready PDF under your firm's name for advisers and wealth managers, as JSON through its API for developers, or inside ChatGPT and Claude through its MCP server. FundFacts works inside ChatGPT and Claude as a connector (a remote MCP server): ask about any fund or ETF by ISIN, ticker or name and the assistant answers from FundFacts' dated figures, fees, risk, holdings, exposure and returns, with fund cards, side-by-side comparisons, holdings overlap and portfolio look-through. - Free API key, no card: https://fundfactsapi.com/signup - Documentation: https://fundfactsapi.com/docs (OpenAPI: https://fundfactsapi.com/openapi.json) - MCP server: https://fundfactsapi.com/api/mcp (set-up for every client: https://fundfactsapi.com/mcp-server) - Pricing: https://fundfactsapi.com/pricing - Site index for AI assistants: https://fundfactsapi.com/llms.txt - Informational data, not investment advice.