What it is
Square, part of Block, hosts its MCP server at https://mcp.squareup.com/mcp with OAuth sign-in; an older /sse endpoint is still served. Only approved clients can connect, to guard against malicious client registration, and the docs list Claude.ai, Claude Desktop, Goose, Cursor and Windsurf. The hosted server reaches production data only, and the whole project is still labelled beta.
For sandbox testing you run the open-source local server with npx square-mcp-server start, an ACCESS_TOKEN and SANDBOX=true. DISALLOW_WRITES=true makes it read-only and SQUARE_VERSION pins the API version. The npm package has had no release since 0.1.2 on 25 April 2025, though the repo README was revised in October 2026 to steer most users to the hosted server.
Rather than one tool per endpoint, it has three: get_service_info to discover methods for a service, get_type_info to fetch parameter details, and make_api_request to call the API. That reaches 38 Square services, including payments, refunds, orders, catalog, inventory, invoices, payouts, labor and loyalty.
Install
https://mcp.squareup.com/mcpOur review
Square takes the same route as Stripe's generic tools: three tools that let the agent discover and call any of 38 Square services. That keeps the tool list small, which helps when several servers share a context window, and means a seller can ask about catalog, orders, customers or payouts without waiting for a purpose-built tool.
The price of generic tools is that the model must find the right method and assemble the request body itself, and the open issues show where that goes wrong. Issue #20 (April 2026) reports make_api_request sending empty arrays for fields such as location_ids, which breaks Orders search, and failing to resolve path parameters. Issue #31 (September 2026) argues that the CreatePayment description tells the model to mint a fresh idempotency key on every call, so a retried request could charge a card twice. Issue #27 notes the generic names collide with other servers' tools, so a model sometimes routes a payments question to Stripe.
The hosted server only reaches production, which sits awkwardly with Square's own advice to test prompts in sandbox first: doing so means running the local package with a token, and the DISALLOW_WRITES read-only switch exists only there. The docs name no OAuth scopes for the hosted server, and publish no rate limits or data-retention terms for the MCP endpoint.
For read-only questions about one seller's business, such as last month's best-selling items or which invoices are overdue, the design works and costs nothing beyond normal Square fees. Writes that touch payments, refunds or inventory deserve a human approval on every call until issues #20 and #31 are closed.
Where it earns its place
The owner of a two-location café on Square
Find out which menu items sold best last month and which barely moved
In Claude, the agent queries orders and catalog through make_api_request on the hosted server. No extra fee; approve each call, since the same tool can also write, and an Orders search failing on location_ids is the open bug #20, not the prompt.
A developer building a Square integration for a retail client
Explore unfamiliar Square endpoints against test data
Run npx square-mcp-server start with SANDBOX=true and DISALLOW_WRITES=true; get_service_info and get_type_info act as an interactive API reference. Free, and nothing touches real money.
Before you commit
- Setup
- Add https://mcp.squareup.com/mcp in an approved client (Claude.ai, Claude Desktop, Goose, Cursor or Windsurf) and sign in with Square; the Claude Desktop config uses npx mcp-remote. For sandbox, run npx square-mcp-server start with ACCESS_TOKEN and SANDBOX=true.
- Integrations
- Three tools: get_service_info and get_type_info for read-only discovery, and make_api_request for reads and writes across 38 services including payments, refunds, orders, catalog, inventory, invoices and payouts.
- Data and privacy
- The hosted server acts on live production data through OAuth; the docs list no scopes and no retention terms. The local server keeps an access token on your machine and can be made read-only with DISALLOW_WRITES=true.
- Cost at scale
- The server is free under Apache-2.0; standard Square processing fees apply to any payment it creates. Each operation usually takes two or three calls (discover, inspect the type, then request), so token use per task runs higher than with purpose-built tools; rate limits are not published in the MCP docs.
- Limits
- Beta; hosted server is production-only; open issues report dropped array parameters (#20), double-charge risk on retried payments (#31) and tool-name collisions with other servers (#27).
What's good
- Reaches 38 Square services through three tools
- Hosted OAuth server with an approved-client list
- Read-only mode and sandbox support in the local server
- Small tool list leaves room for other servers in context
What's not
- Beta, with an npm package unchanged since April 2025
- Hosted server is production-only with no read-only switch
- Open bugs: dropped array parameters, idempotency wording that risks double charges
- Generic tool names collide with other servers
Best for
Square sellers and developers who want an assistant to query sales, orders and catalog data.
Alternatives
Square MCP Server: common questions
- Is Square MCP Server worth it?
- Square's whole API behind three tools: clever for reading sales data, risky for anything that moves money while its beta bugs stay open. We rate it 3.6 out of 5.
- How much does Square MCP Server cost?
- Free and open source (Apache-2.0); normal Square fees apply.
- What are the downsides of Square MCP Server?
- Beta, with an npm package unchanged since April 2025; hosted server is production-only with no read-only switch; open bugs: dropped array parameters, idempotency wording that risks double charges; generic tool names collide with other servers.
- Who is Square MCP Server best for?
- Square sellers and developers who want an assistant to query sales, orders and catalog data.
- How much does Square MCP Server cost for a team or in production?
- The server is free under Apache-2.0; standard Square processing fees apply to any payment it creates. Each operation usually takes two or three calls (discover, inspect the type, then request), so token use per task runs higher than with purpose-built tools; rate limits are not published in the MCP docs.
- Is Square MCP Server safe for company data?
- The hosted server acts on live production data through OAuth; the docs list no scopes and no retention terms. The local server keeps an access token on your machine and can be made read-only with DISALLOW_WRITES=true.
- What are the best Square MCP Server alternatives?
- The closest alternatives we have reviewed are Stripe MCP, PayPal MCP Server and Shopify Dev MCP.
Answers checked Oct 23, 2026.