# Moltline Merchant Maths Muse connector

From musedirectory.ai, the independent directory of Meta Muse connectors. Not affiliated with Meta.

## Moltline Merchant Maths

Calculate processor fees, invoice totals, discounts, prorations and payment plans for your business.

- Record: https://musedirectory.ai/connector/moltline-merchant-maths
- Category: Finance & Bills
- Developer: Moltline Studio (https://moltlinestudio.com/servers.html#merchant)
- Muse status: Extra setup. Not in Muse's Connectors list yet. Muse can still use it: its page gives you a request to paste into Muse.
- Health: Working, 556ms, checked 2026-09-28T10:01:43Z
- Endpoint: https://mcp.moltlinestudio.com/merchant
- Auth: No account needed; Pricing: unknown
- Screening: Screened, no issues found (2026-09-24T16:46:02Z)
- Source: Found in the official MCP Registry (com.moltlinestudio/merchant) https://registry.modelcontextprotocol.io/v0/servers?search=com.moltlinestudio%2Fmerchant

Helps merchants and small business owners compute payment processor fees (Stripe, PayPal, Square, Shopify), invoice totals with tax and discounts, stacked discounts, prorated charges for partial billing periods, and installment payment schedules. Three tools are free; three require a license.

Example request: "How much will I net after Stripe fees if I charge $1000 across 10 transactions?"

How to connect: Not in Muse's Connectors list yet, but Muse can still use it. Paste this into Muse: "Use Moltline Merchant Maths to help me. It is a free service with an MCP server at https://mcp.moltlinestudio.com/merchant. It does not need an API key. Ask me before you share anything with it." Muse asks before it shares anything with the app's site. Meta does not review apps used this way, so only use ones you trust. We tested this in the Muse app on September 24, 2026: Muse used an app's link directly this way and returned a live answer.

Tools:
- processor_fees: Break down payment-processor fees: fee, net, and effective rate. FREE. Uses editable presets for stripe/paypal/square/shopify (verify current rates) or your own custom_pct + custom_fixed. Typical input {"amount": 1000, "processor": "stripe", "transactions": 10} returns {"gross": 
- charge_to_net: Compute the gross price to charge so you net a target after fees. FREE. 'Charge X to receive Y' after percentage + fixed processor fees. Typical input {"net_target": 100, "pct_fee": 2.9, "fixed_fee": 0.30} returns {"charge": 103.4, "fee": 3.4, "net": 100.0}. The inverse of proces
- invoice_total: Total an invoice: per-line totals, subtotal, discount, tax, grand total. FREE. Typical input {"line_items": [{"desc": "Design", "qty": 2, "unit_price": 50}], "tax_pct": 8.5, "discount_pct": 10} returns {"lines": [{"desc": "Design", "qty": 2, "unit_price": 50, "line_total": 100.0}
- discount_stack: Stack discounts correctly: sequential vs additive comparison. PREMIUM (license). The two methods differ — this shows both, the final price, and the true total discount. Typical input {"price": 200, "discounts_pct": [20, 10]} returns {"original": 200, "sequential_price": 144.0, "s
- proration: Compute a prorated charge or refund for a partial billing period. PREMIUM (license). Typical input {"amount_per_period": 90, "days_used": 10, "days_in_period": 30} returns {"days_used": 10, "days_in_period": 30, "prorated_charge": 30.0, "prorated_refund": 60.0, "answer": 30.0}. U
- installment_plan: Split a total into an installment schedule with optional deposit. PREMIUM (license). Rounding remainders land on the final payment so the schedule always sums exactly. Typical input {"total": 1000, "installments": 3, "deposit_pct": 10} returns {"deposit": 100.0, "payments": [300.

Screening checks:
- MCP handshake: pass (Answered in 267ms)
- Domain against threat feeds (Cloudflare security DNS): pass (mcp.moltlinestudio.com, moltlinestudio.com not flagged)
- Published packages against the OSV malicious-package database: n/a (No npm or PyPI package published)
- Hidden instructions or invisible characters in tool text: pass (6 tools read, nothing found)
- Inputs asking for passwords, card numbers or seed phrases: pass (None found)
- Domain and redirects: pass (No redirects off the domain)
- AI review of purpose and tool behavior: pass (No concerns)