Search and read Sellsy companies, contacts, opportunities, invoices and tasks; create records. Hosted by usefulapi: connect it to Claude, ChatGPT, Cursor or any MCP client.
Turn on the Sellsy connector, then ask in plain words. The AI picks the tools.
For small businesses and sales teams who manage customers, quotes and invoices in Sellsy.
Searches invoices by status, such as due or late, date, currency or related company, and lists the payments on an invoice.
Finds a company by name, email, VAT or other fields, lists its contacts, and searches the estimates linked to a company.
Searches opportunities by pipeline, step, status, amount, owner or due date, and lists the pipelines and their steps.
Looks up the pipeline and its steps, then creates an opportunity linked to a company, individual or contact.
Changes dataCreates a company, a private individual or a contact person. Companies and individuals can be prospects, clients or suppliers.
Changes dataCreates a task with a label and due date-time, or adds a note to a company, individual, contact, opportunity or document. Notes are not sent to the customer.
Changes dataThe login page asks for your Client ID and Client secret.
In Sellsy open Settings → Developer portal → API V2, create a client of type Personal and tick the scopes you want to use (staffs: read is required to identify your account; for example also companies, contacts, opportunities, estimates, invoices, items, tasks, comments: read, plus write for the records you want to create or, for opportunities, move). The client acts with the rights of your own Sellsy user and reaches your customers’ names, emails and invoices. Your credentials are used only to call the Sellsy API on your behalf and to derive a private account id from your Sellsy account; they are never shown to anyone.
Team and Enterprise: an Owner adds the connector for the organization first.
No Add custom MCP server option? It depends on your account or workspace settings: see OpenAI's guide.
Run this command, then run /mcp in Claude Code to log in:
Add to Cursor or add this to ~/.cursor/mcp.json:
{
"mcpServers": {
"sellsy": {
"url": "https://sellsy.usefulapi.io/mcp"
}
}
} Add to VS Code or add this to .vscode/mcp.json:
{
"servers": {
"sellsy": {
"type": "http",
"url": "https://sellsy.usefulapi.io/mcp"
}
}
} Run these commands. The second one opens the login page:
Windsurf, Cline, Zed and other MCP clients: add this URL as a remote MCP server (Streamable HTTP). The client then opens the login page in your browser.
Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your Client ID and Client secret. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.
| Plan | Price | Limit |
|---|---|---|
| Free | $0 | 50 tool calls / month |
| Proper account | $9/mo · $90/yr | 10,000 tool calls / month |
| Pro+per account | $39/mo · $390/yr | 100,000 tool calls / month |
Each paid plan covers this Sellsy server only. Ask your AI to run sellsy_upgrade and choose Pro or Pro+, billed monthly or yearly (it returns a Stripe Checkout link). If you already have Pro, ask to change it to Pro+. The change requires your confirmation, keeps your billing interval and charges the price difference for the rest of the period immediately. Cancel any time with sellsy_cancel_subscription: your paid plan continues to the end of the paid period, with no refund for the current period, and asking to resume the same plan with sellsy_upgrade before then undoes the cancel. Or write to [email protected].
sellsy_searchsellsy_list_companiessellsy_search_companiessellsy_get_companysellsy_list_company_contactssellsy_list_individualssellsy_search_individualssellsy_get_individualsellsy_list_contactssellsy_search_contactssellsy_get_contactsellsy_list_opportunitiessellsy_search_opportunitiessellsy_get_opportunitysellsy_list_opportunity_pipelinessellsy_list_pipeline_stepssellsy_list_estimatessellsy_search_estimatessellsy_get_estimatesellsy_list_invoicessellsy_search_invoicessellsy_get_invoicesellsy_list_invoice_paymentssellsy_list_orderssellsy_search_orderssellsy_get_ordersellsy_list_credit_notessellsy_get_credit_notesellsy_list_itemssellsy_search_itemssellsy_get_itemsellsy_search_paymentssellsy_list_taskssellsy_search_taskssellsy_get_tasksellsy_list_task_labelssellsy_search_commentssellsy_list_staffssellsy_create_companysellsy_create_individualsellsy_create_contactsellsy_create_opportunitysellsy_move_opportunitysellsy_create_commentsellsy_create_tasksellsy_usage_statussellsy_request_featuresellsy_upgradesellsy_cancel_subscriptionFind late or unpaid invoices. Look up a company with its contacts and quotes. Review open opportunities in the pipeline. Create an opportunity for a customer. Add a company, individual or contact. Create a task or add a note to a record. See what you can do for the details.
No. usefulapi is an independent service. It is not affiliated with or endorsed by Sellsy. The server calls the Sellsy API with your own Sellsy access, so it sees only the data that your account can see.
Yes. In Claude, add this server's URL as a custom connector. In ChatGPT, add it as a custom MCP server in Plugins. Then log in once. Cursor, VS Code, Claude Code and Codex work too. See the setup steps.
The login page asks for your Client ID and Client secret. See Before you connect for where to find them.
No. Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your Client ID and Client secret. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.
The login stores them encrypted in the authorization grant of your connection. The server uses them to call the Sellsy API for you and to derive a private account id for usage metering. usefulapi does not show them on any page or in any reply. To stop all access, remove the connector and change or delete these credentials in Sellsy.
Yes, if you approve it. 7 of the 45 Sellsy tools can create or change data. The other 38 are marked read-only. Most MCP clients ask you to approve a tool call before it runs.
The Free plan gives 50 tool calls / month. Pro costs $9/mo or $90/yr, with 10,000 tool calls / month. Pro+ costs $39/mo or $390/yr, with 100,000 tool calls / month. Each subscription covers this Sellsy server only. Cancel any time: your paid plan then runs to the end of the paid period. Run sellsy_usage_status to see how many calls you used.
Ask the AI to run sellsy_upgrade and choose Pro or Pro+, billed monthly or yearly: it returns a Stripe Checkout link. If you already have Pro, ask to change it to Pro+. After you confirm, your existing subscription changes in place, keeps its billing interval and charges the price difference for the rest of the period immediately. To cancel, run sellsy_cancel_subscription. Your paid plan continues to the end of the paid period.
Tell the AI what you wanted to do. It can send the request with sellsy_request_feature. We store the text with the server name, the type of AI client and the tool you tried, not with your account, and read every request when we plan new tools. You can send up to 5 requests per day.
Any client that supports remote MCP servers (Streamable HTTP) with OAuth login: Claude (web and desktop), Claude Code, ChatGPT, Codex, Cursor, VS Code, Windsurf and others.
This is a Model Context Protocol endpoint — meant to be connected from an AI client, not opened in a browser. An invalid_token response at the URL is the auth gate working as designed; clients authenticate automatically.
Need a tool this server does not have, or a connection to another system? We build custom integrations and MCP servers.