Connectors Guide

Connector from the MCP registry

Index One

Query financial index data, run backtests, and deploy systematic investment strategies on Index One.

The address

https://api.indexone.io/mcp
Transport
Streamable HTTP
Sign-in
Optionally, a key in the x-api-key header. The publisher says: "Index One team API key. Only needed by clients that cannot do OAuth; OAuth-capable clients (Claude connectors and similar) sign in with an Index One account instead and send no header. Create keys in the console under Team API Keys."
Published by
indexone.io (domain checked by the registry)
Registry name
io.indexone/mcp, version 1.4.0
In the registry since
17 July 2026

How to add Index One to Claude

  1. In Claude on the web or desktop, open Customize, then Connectors (Settings > Connectors in some versions).
  2. Press + Add, then Add custom connector.
  3. Name it Index One, paste the address and press Continue.
  4. Under Request headers, add the header x-api-key with the value YOUR_KEY. Press Add. The registry entry does not say the format; a header like this usually takes the key alone, but check the publisher's docs. The registry entry says the key is optional: you can also leave the header out and sign in when you connect.
  5. Press Connect next to it and sign in if it asks.
  6. In a chat, press +, then Connectors, to switch it on.

On your phone: connectors belong to your Claude account. Add it once on claude.ai or in the desktop app, and it is in the Claude app for iPhone and Android too: in a chat, press +, then Connectors, and switch it on.

Claude's free plan allows one custom connector; paid plans allow more. On Team and Enterprise plans an owner adds it once under Organization settings > Connectors, and each member then presses Connect. Claude's help page

How to add it to ChatGPT

  1. On chatgpt.com, on a Plus, Pro, Business, Enterprise or Edu plan, turn on Developer mode (Settings > Security and login, or Settings > Apps > Advanced settings in some versions).
  2. Open Settings > Apps and create an app (the + or Create button).
  3. Name it Index One, paste the address, choose OAuth (or No authentication if the server is open) and press Create.
  4. Sign in when it asks.
  5. In a new chat, press + and pick Index One.

ChatGPT's custom apps cannot send a key header; choose OAuth, which the registry entry says this server also offers.

ChatGPT's menus move now and then; the idea stays the same: a new app, this address, OAuth. On business plans an admin may have to allow custom apps first.

Claude Code

claude mcp add --transport http index-one https://api.indexone.io/mcp --header "x-api-key: YOUR_KEY"

The registry entry does not say the format; a header like this usually takes the key alone, but check the publisher's docs. The key is optional here: leave out --header and run /mcp to sign in instead.

Source

This page is made from the official MCP registry on 30 October 2026 and has not been checked by hand. A connector acts as you: check who publishes it before you connect anything that can change your data.