Read invoices, quotes, contacts, financial reports and bank reconciliation in Zero Plus One. Hosted by usefulapi: connect it to Claude, ChatGPT, Cursor or any MCP client.
Turn on the Zero Plus One connector, then ask in plain words. The AI picks the tools.
For bookkeepers and finance teams that keep their books in Zero Plus One.
Read the open invoices report and the aged receivables report. Open the invoices that need action to see their details.
Read the profit and loss, cash flow and balance sheet reports. Ask the assistant to explain the main figures in plain words.
Read the VAT 201 return figures for a period. Read the tax rates set up in the organization next to them.
Read the reconciliation summary for one ledger account. List the bank lines that still need matching and the suggested matches.
List the customers and suppliers, then open one to read its record.
The login page asks for your Zero Plus One API key.
Create the key in Zero Plus One → Settings → Developer. Tick only the scopes you need: View invoices, View customers & suppliers, View financial reports and View reconciliation suggestions. Your key is used only to call the API on your behalf and to derive a private account id; it is 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": {
"zero-plus-one": {
"url": "https://zero-plus-one.usefulapi.io/mcp"
}
}
} Add to VS Code or add this to .vscode/mcp.json:
{
"servers": {
"zero-plus-one": {
"type": "http",
"url": "https://zero-plus-one.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 Zero Plus One API key. 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 user | $9/mo · $90/yr | 10,000 tool calls / month |
| Pro+per user | $39/mo · $390/yr | 100,000 tool calls / month |
Each paid plan covers this Zero Plus One server only. Ask your AI to run zeroplusone_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 zeroplusone_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 zeroplusone_upgrade before then undoes the cancel. Or write to [email protected].
zeroplusone_list_invoiceszeroplusone_get_invoicezeroplusone_list_contactszeroplusone_get_contactzeroplusone_list_credit_noteszeroplusone_get_credit_notezeroplusone_list_quoteszeroplusone_get_quotezeroplusone_list_recurring_invoiceszeroplusone_get_recurring_invoicezeroplusone_list_tax_rateszeroplusone_get_tax_ratezeroplusone_get_profit_and_losszeroplusone_get_balance_sheetzeroplusone_get_trial_balancezeroplusone_get_cash_flowzeroplusone_get_vat_returnzeroplusone_get_kpi_summaryzeroplusone_get_aged_receivableszeroplusone_get_aged_payableszeroplusone_get_open_invoiceszeroplusone_get_reconciliation_summaryzeroplusone_list_reconciliation_lineszeroplusone_get_reconciliation_suggestionszeroplusone_usage_statuszeroplusone_request_featurezeroplusone_upgradezeroplusone_cancel_subscriptionChase invoices that are still open. Review profit, cash flow and the balance sheet. Check the VAT 201 figures against the tax rates. Find bank lines that still need reconciling. Look up a customer or supplier record. See what you can do for the details.
No. usefulapi is an independent service. It is not affiliated with or endorsed by Zero Plus One. The server calls the Zero Plus One API with your own Zero Plus One 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 Zero Plus One API key. See Before you connect for where to find it.
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 Zero Plus One API key. 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 Zero Plus One 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 Zero Plus One.
All 24 Zero Plus One tools are marked read-only.
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 Zero Plus One server only. Cancel any time: your paid plan then runs to the end of the paid period. Run zeroplusone_usage_status to see how many calls you used.
Ask the AI to run zeroplusone_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 zeroplusone_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 zeroplusone_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.