Mercury

Mercury started as the bank for tech startups. It has quietly become the default operating account for mid-market B2B companies that want their finance stack to behave like software. The combination of clean UI, real API access, integrated treasury, and tight accounting integrations is the reason 1 in 3 startups bank with it, and why a growing slice of $5M to $200M companies have moved off legacy bank portals entirely.

What Mercury Does

Mercury is a fintech platform offering business banking services through partner banks Choice Financial Group and Column N.A., with FDIC insurance up to $5M via sweep networks. It sits at the centre of the finance function for a growing B2B company, bundling what would normally be five or six separate tools.

• Checking and savings, zero monthly fees, no minimums, unlimited free USD wires and ACH.
• Corporate credit cards with 1.5% unlimited cashback, no personal guarantee, and granular per-card spend controls.
• Bill pay, invoicing, and reimbursements built into the same account, with approval flows that map to your org.
• Treasury at yields up to 3.66% via J.P. Morgan and Morgan Stanley portfolios, available once total balances cross $250K.
• REST API with scoped tokens, IP allow-listing, webhooks, and a sandbox environment for building custom finance workflows.
• Native integrations with QuickBooks, Xero, NetSuite, Stripe, and a long list of accounting and operational tools.
• An MCP server so AI agents (including Claude and ChatGPT) can read balances, categorise transactions, and trigger workflows on your behalf.

Mercury's AI

Mercury's AI features are not a separate product. They are stitched into the workflows finance teams already run. The bill pay flow reads incoming invoices, extracts vendor, amount, due date, and GL code, and remembers past recipients so repeat bills require almost no input. Transaction categorisation learns from your past tagging, so the longer Mercury is in use the cleaner your books get with no extra effort. A universal search lets you find any transaction, vendor, or initiate a transfer in a single bar, and the MCP server makes the same primitives available to AI agents you build on top.

Automations We Build with Mercury

Mercury is one of the easiest finance tools to build on, and that is exactly where most teams stop short. They use it as a nicer bank UI and never wire it into the rest of the stack. The Moonira plays we run on top of Mercury treat it as a programmable finance layer, not a place to log in.

• Auto-sweep into Treasury once operating balance crosses a defined threshold, with a sweep-back rule when AR drops below 60 days of runway.
• Closed-deal to invoice automation: HubSpot or Salesforce deal moves to Closed Won, Mercury creates the invoice, dunning sequence runs, paid status updates the CRM.
• Vendor categorisation rules that push pre-tagged transactions into QuickBooks or NetSuite via the API, with exceptions routed to a Slack channel for finance to clear in minutes.
• New-hire card provisioning triggered by your HRIS, with the right limit, category locks, and approver baked in before day one.
• Daily finance brief delivered to Slack or email: live balance, week-on-week burn, AR aging, treasury yield, and any flagged transactions over a threshold.
• Subscription duplicate detection that watches Mercury card spend, flags two SaaS charges from the same vendor, and routes a cancel-or-keep decision to the owner.
• Multi-entity treasury views for groups that run several legal entities through Mercury, consolidated into one cash dashboard for the CFO.

Why Teams Choose Mercury

• Real API access. Unlike legacy banks, you can build directly against Mercury with scoped tokens, webhooks, and a sandbox, so finance workflows can live in code instead of spreadsheets.
• Treasury yield without a separate broker. Up to 3.66% on idle cash through J.P. Morgan and Morgan Stanley portfolios, managed inside the same account.
• Spend controls that scale. Unlimited virtual cards, approval flows, and per-card category locks let a 200-person org run clean expense governance without an admin army.
• Accounting integrations that actually work. Two-way sync with QuickBooks, Xero, and NetSuite means transactions show up in the GL already tagged, cutting close time noticeably.
• A UI finance teams will actually open. The portal is fast, the data is searchable, and reports are exportable in formats your auditors will accept.

Mercury integrates natively with QuickBooks, Xero, NetSuite, Stripe, and a long tail of CRMs, expense, and HR tools, and its API and MCP server cover anything that is not on the native list. Pricing starts free for the base account, with Mercury Plus at $29.90/month and Mercury Pro at $299/month adding higher invoicing limits, more reimbursable users, and a relationship manager. Treasury fees run 0.15% to 0.6% annualised depending on tier. That is the build we do on top of it: Mercury becomes the financial spine of the company, and the workflows around it stop relying on a finance hire copy-pasting from a banking portal.