Connecting Claude and ChatGPT (MCP)
ERPJS connects to AI chats — Claude and ChatGPT — through the ERPJS MCP server: you keep your books with plain phrases in the chat, with the permissions of the ERPJS user the assistant was connected under. What exactly it can do is in the "What the assistant can do" section below.
MCP server address — the same for everyone: https://s.erpjs.biz/mcp
Video and a guide with example phrases: the connection video with a 3-minute live demo is on YouTube (in Ukrainian, the steps are the same); the article "Invoice in one sentence — accounting in your chat" on erpjs.biz.
Where to connect:
- Claude: Settings → Connectors → Add custom connector
- ChatGPT: Settings → Apps → Advanced settings → Create app (OAuth)
Your system address and the MCP token are entered afterwards — on the "Вхід до ERPJS" sign-in page, which opens by itself.
What to prepare
- Your system address — the one you open ERPJS with in the browser. Copy it from the address bar (it looks like
https://s.erpjs.biz/your-system). - A separate user for the assistant. One user cannot work in the system and via MCP at the same time: the assistant's sign-in logs you out. Create a card for the assistant in the Users register and give it a role with the permissions it needs (Access rights).
- This user's MCP token. It is created by the user card menu item "Generate MCP token" — this needs the right to edit users. The token is shown only once, so copy it right away. Instead of the token you can sign in with the assistant user's login and password.
What goes where
ERPJS itself has no separate setting for the connection: you set it up in Claude or ChatGPT. From ERPJS you only need your system address and the MCP token: the "Generate MCP token" item in the menu of the assistant user's card (Modules → System → Registers → Users) creates it and shows it once.
| Where | What to enter |
|---|---|
| Claude — Settings → Connectors → Add custom connector | a name (for example, ERPJS) and the MCP server address https://s.erpjs.biz/mcp |
| ChatGPT — Settings → Apps → Advanced settings → Create app | a name, the MCP server address https://s.erpjs.biz/mcp and OAuth authorization |
| The ERPJS sign-in page ("Вхід до ERPJS") — opens by itself after Connect | your system address and the MCP token (or the assistant user's login and password) |
Your system address and the token are not entered in Claude or ChatGPT — only on the "Вхід до ERPJS" page.
Claude — 5 steps
- In Claude, open Settings → Connectors → Add custom connector.
- Enter any name (for example, ERPJS) and the server address
https://s.erpjs.biz/mcp. Click Add. - Click Connect — the ERPJS sign-in page opens. It is in Ukrainian: the heading reads "Вхід до ERPJS".
- In the "URL вашої системи" field (your system URL), paste your system address — not the MCP server address.
- Enter the MCP token (the "MCP-токен" field) or the login and password, and click "Дозволити доступ" (allow access). Done.
In Claude, custom connectors work even on the free plan.
ChatGPT
The path in ChatGPT differs from Claude:
- In ChatGPT, open Settings → Apps → Advanced settings → Create app.
- Enter a name (for example, ERPJS), the server address
https://s.erpjs.biz/mcpand the OAuth authorization method. - The same ERPJS sign-in page ("Вхід до ERPJS") opens: in the "URL вашої системи" field paste your system address, enter the MCP token (or the login and password) and click "Дозволити доступ" (allow access).
- The new app appears in your Apps list, and ERPJS becomes available in your chats.
What custom connections can do in ChatGPT depends on your plan.
What the assistant can do
- Read your books — registers and reports: "Show the receivables of customer Concord", "How much cash came in this week?", "Show the stock levels".
- Create and change records — invoices, product and customer cards, tech cards, purchase orders: "Create an invoice: customer Kvitka, boxing helmet, 3 pcs — and send it to me as a PDF".
- Delete records — in two steps, with confirmation; a record with attached files is not deleted.
- Work with files — export a report to Excel or a document to PDF with its print form, attach a file to a record (up to 10 MB), read an attached one.
- Answer from the ERPJS documentation — the same articles as on this site.
In one request the assistant gets at most 1000 register rows — it fetches larger selections in portions.
Documents from the chat can stay unposted: while you are getting to know the assistant, review each one and post it yourself. Once you trust it, ask the assistant to post right away.
Security and access
- The assistant sees and does only what its user's role allows: an accountant's assistant sees accounting, a sales manager's assistant sees sales.
- To revoke access: in the assistant user's card, first click "Generate MCP token" again — the previous token stops working — then "Force logout" (administrator rights needed) to cut an already open connection at once: without it, a session opened with the old token lives on for up to 8 hours. The order matters — after a force logout without a new token the assistant signs straight back in. If the assistant signed in with a login and password, change the password: a password change closes its open sessions too.
- A user with the "Deny login" or "Closed" flag cannot sign in via MCP, just as they cannot sign in to the system; setting the flag also closes the sessions already open at once — the fastest way to switch the assistant off.
Common situations
I get logged out while the assistant works. You and the assistant work under the same user. Create a separate one for the assistant — and work in parallel.
The "Вхід до ERPJS" page does not accept the token. Only the most recently generated token is valid. You cannot view it again — only generate a new one. Also check the "URL вашої системи" field: it must hold your system address from the browser's address bar.
The assistant does not see a register or report. That is the assistant user's permissions: check its role (Access rights).
How much does it cost? MCP is available on the free ERPJS plan too (it has no time limit). In Claude, custom connectors work even on the free plan; in ChatGPT, it depends on your plan.
I don't have ERPJS yet. Sign up for the free plan: erpjs.biz/cabinet/register. Then connect the assistant with this guide and start with a simple phrase such as "show the stock levels".