The Puzzle and Mercury team worked together to create a custom API for accounting automation, allowing capabilities not possible in QuickBooks or Xero. It allows for secure, read-only access to all your Mercury accounts across cash, card, and spend.
TLDR:
Puzzle worked with Mercury to create a custom onboarding flow that literally takes one click to set up your accounting for scale. Why didn’t this exist before? We don’t know either, but now it does.
Here is what happens after the click. You approve read-only access through OAuth, and Puzzle pulls in your connected Mercury cash, card, and spend accounts along with their transactions. The AI then starts categorizing and matching them right away, with about 90% categorized automatically, and anything it is less than 99% confident about is flagged for your review. Daily reconciliation runs natively with Mercury, and you can connect Stripe, Ramp, Brex, or Gusto afterward in about two minutes each.
Mercury is widely used by venture-backed startups, so more founders arrive with a Mercury account already set up and expect their accounting to match that speed. In 2026, your Mercury feed also connects to Puzzle's AI suite: AI Cowork prepares work like categorizing a batch of Mercury transactions for your review, and AI Chat answers questions from your actual books (read-only). Nothing changes in the ledger until you approve it, and reviewing AI-categorized transactions takes roughly 15 to 20 minutes per week. Startups still doing manual categorization and month-end close have a harder time matching peers who track burn rate and runway in real time. The Puzzle and Mercury integration was built with that in mind, which is why one-click setup and automatic categorization are the baseline.
Mercury received conditional OCC approval in April 2026 to launch its own bank, Mercury Bank, N.A. In September 2026, it received conditional FDIC approval for deposit insurance. The Federal Reserve still needs to approve its bank holding company application, and Mercury Bank is projected to open in 2027. In its May 2026 Series D announcement, Mercury reports more than 300,000 customers, including, by its own count, one in three U.S. startups. Elsewhere in the stack, Capital One agreed in January to buy Brex for $5.15 billion and completed the acquisition on April 7, 2026. Banks and card providers are consolidating faster than most founders can track. The practical move is to keep your books in accounting software with direct integrations to each provider (Mercury, Brex, Ramp, Stripe, Gusto), so a change on the banking side means reconnecting a feed, not rebuilding your ledger.
The Puzzle and Mercury team worked together to create a custom API for accounting automation, going beyond what generic bank feeds provide. All you have to do is authenticate via OAuth.
Yup. Our system typically takes ~3 minutes for most startups, and you will see your verified financial statements, startup metrics, spending trends, financial health insights… all generated by our software. Puzzle is also an AI-native accounting firm, so a Puzzle bookkeeper or a vetted partner firm can review the books for any final polishing before fundraising. Puzzle does not offer tax services.
Puzzle is an AI-native generative accounting solution, meaning our software and AI organize your accounting according to GAAP standards. With Mercury, Puzzle categorizes and matches transactions automatically, thanks to Mercury's product and APIs. Compare this to a bank like Chase, which connects indirectly through Plaid, or any bank you load by CSV upload: we can still automate your future monthly financials, but there is no custom API behind the feed, and a CSV carries only date, amount, and description, so you add vendor and category afterward. In QuickBooks, for example, transactions are categorized and matched by hand in your accounts, which is slow, expensive, and error-prone.
| Puzzle | QuickBooks | |
|---|---|---|
| Accounting basis | Cash and accrual in a single solution | Designed for cash accounting; accrual requires manual spreadsheet schedules |
| Audit trail | Immutable, append-only ledger: every entry traced to the source transaction | Edit-based audit log; entries can be changed after posting |
| Mercury integration | Categorizes and matches Mercury transactions automatically via custom API | No native Mercury integration; manual entry or third-party connector |
| Monthly close time | ~15 to 20 minutes per week (90 min/month) | 5 to 7 hours per month |
| Startup metrics | Burn rate, runway, ARR: built in, real-time | Not included; requires separate tools or manual calculation |
| Real-time alerts | Monitors and alerts on material changes in cash, spend, or burn | No built-in real-time financial monitoring |
QuickBooks lets entries be edited after posting, so tracing who changed what, when, and why takes extra effort. Puzzle is an immutable, append-only system where you can trace your financial statements to the transaction, allowing anyone to verify anything, anytime.
QuickBooks is designed for cash accounting. Venture-backed startups and revenue-generating companies generally need accrual accounting for investor-ready financials, but it is more expensive and time-consuming as you need to do accrual schedules in spreadsheets and then manually enter them into QuickBooks. Puzzle gives you both cash and accrual accounting in a single solution.
QuickBooks is designed to generate your financial statements, ignoring how valuable all the data underneath accounting is. Puzzle also monitors and alerts you to material changes in cash, spend or burn, all in real-time, all included.
Puzzle gives you what you need (burn, runway, and ARR, all non-accounting metrics) plus the financial statements you need to close that next round of funding with confidence and accuracy. We also offer free templates for financial planning and budgeting and connect with popular tools like Causal, Runway, Meow, and Sturppy.
QuickBooks is very manual, which is why it takes so long for bookkeepers to close your books. With Puzzle’s automation, built-in collaboration, and AI categorizer, Puzzle targets 15-20 minutes per week (about 90 minutes per month) for an early-stage company to complete accounting.
See for yourself at puzzle.io.
Puzzle, connected to Mercury, gives you real-time burn rate, runway, and cash position, updated daily with no controller required. Because Puzzle categorizes and matches Mercury transactions automatically, your books stay current without anyone manually touching transactions. You see actuals, not month-old estimates. For startups that also use Ramp or Brex for spend, Puzzle pulls those feeds in as well, so your full fintech stack (Mercury, Ramp, Brex, Stripe, Gusto) feeds one real-time view.
Tools like Runway or Float can sit on top of Puzzle's data for forecasting if you want a dedicated cash-flow planning layer, but for most early-stage teams, the burn and runway numbers Puzzle surfaces directly are enough to run weekly financial reviews without hiring a finance team.
Puzzle has native integrations with Mercury, Stripe, Ramp, Brex, Gusto, and more, built through direct APIs instead of generic bank-feed connectors. The Mercury integration in particular uses a custom API that gives Puzzle read-only access to every account (cash, card, spend) and lets Puzzle categorize and match Mercury transactions automatically. Stripe revenue syncs with proper accrual treatment so deferred revenue and fees are handled correctly. Ramp and Brex card transactions are categorized automatically as they clear. QuickBooks and Xero typically connect to these tools through third-party connectors, while Puzzle uses direct APIs. Puzzle brings all of these together in a single GAAP-compliant ledger, updated in real time.
Connect Stripe to Puzzle and set revenue recognition policies by product or subscription type. Puzzle then defers each invoice and recognizes it over the correct period, applied at the invoice line-item level, so annual prepaid plans, monthly subscriptions, and add-ons each follow their own schedule without a deferred revenue spreadsheet. You confirm the schedules in bulk (up to 100 items per batch), so nothing posts to your books without your approval. Puzzle also maintains cash and accrual books at the same time, which lets you see cash collected in Mercury next to revenue recognized in Stripe. One limit to plan for: revenue recognition is Stripe-centric, so invoices billed outside Stripe still need manual journal entries. In QuickBooks, the same work means building accrual schedules in spreadsheets and keying them in by hand.
The QuickBooks migration is straightforward: connect your Mercury account (one click, OAuth), then connect any other integrations (Stripe, Ramp, Brex, Gusto). Puzzle pulls in your full transaction history automatically, so you don't need to export or manually re-enter anything. On timing, the cleanest approach is to start Puzzle at the beginning of a new month so your historical books stay in QuickBooks and your go-forward books live in Puzzle. Cancel your QuickBooks subscription once you've confirmed the new month's data is flowing and balanced correctly.
Puzzle is built for venture-backed and revenue-generating startups that need GAAP-accurate books without a full-time controller, typically pre-seed through Series B. If you're running on Mercury and fintech tools like Stripe, Ramp, or Brex, Puzzle is purpose-built for your stack. What Puzzle is not: a fit for retail businesses, cash-basis freelancers, or companies that need a full mid-market ERP. It's right-sized for the high-growth startup stage.
Partly. Puzzle's multi-entity portal gives you one login for multiple companies at no additional charge, and each entity maintains its own GAAP-compliant books. Puzzle has no native consolidations or eliminations across parent and subsidiary entities: consolidated views rely on a third-party integration partner (Join), with separate per-entity accounts under one centralized login. Class and location segmentation is available on the Complete plan and above. If you need full consolidated statements with eliminations, confirm your structure with the Puzzle team first.
Puzzle's AI goes beyond basic categorization. It can split transactions across multiple accounts or cost centers, flag potential fixed assets for capitalization review, surface unusual spend patterns, and generate on-demand summaries of spending by category or department (effectively a mini P&L on request). The key design principle: the AI does the work, but you approve before anything touches your books. That human-in-the-loop step is what makes AI-assisted accounting trustworthy for audit and fundraising purposes, and it's what separates Puzzle from tools that push autonomous changes directly to the ledger.
Puzzle supports classifications and departments, which let you tag transactions (including entire accounts) to specific cost centers like Marketing, Sales, Engineering, or G&A. Once set up, you can filter your P&L and spending reports by department to see exactly where money is going without building manual spreadsheet pivots. Setup takes a few minutes: define your department list, then apply tags at the transaction level (manually or via rules that auto-tag based on vendor or account). For Mercury users, transaction data comes in with enough metadata that most tags can be applied automatically from day one.
At 10 people on SaaS with Stripe and Mercury, you need accrual accounting (for GAAP-correct revenue recognition and fundraising-ready financials), real-time visibility into burn and runway, and tight integrations with the tools you already use, without the cost or complexity of a mid-market ERP like NetSuite. Puzzle is purpose-built for this stage: the Mercury integration takes one click to set up, Stripe revenue is recognized correctly under accrual automatically, and your financial statements are accurate and ready without a full-time bookkeeper. QuickBooks can handle the basics but defaults to cash accounting, requires manual accrual schedules in spreadsheets, and closes take 5 to 7 hours per month versus Puzzle's 15 to 20 minutes per week. Xero is a strong international generalist, but its AI is added onto an existing product and it is not built around startup metrics like ARR, burn, and runway alongside your P&L. For a full side-by-side, see our breakdown of the best QuickBooks alternatives for startups.
Mercury and Brex connect directly, and the Mercury setup is a one-click OAuth flow. Stripe and other supported tools (Ramp, Gusto, Rippling, Deel) connect in about two minutes each. A bank like Chase connects indirectly through Plaid, or you can upload a CSV from the transactions section. Once a feed is live, your cash position, P&L, and balance sheet update daily. Automatic daily reconciliation works natively with Mercury and Ramp. For other banks, plan on CSV uploads to keep reconciliation current. CSV imports carry only date, amount, and description, so you add vendor and category afterward.
Each payment source lands in the ledger through its own feed. Card and ACH activity arrives from your bank or card connection, Stripe payments arrive from Stripe, and checks show up as bank transactions once they clear in the connected account (or in your CSV upload). Puzzle's AI then categorizes about 90% of transactions automatically, and you review and finalize them, which takes roughly 15 to 20 minutes per week. Anything the AI is less than 99% confident about is left uncategorized and flagged for your review instead of guessed.
Not with Puzzle. Puzzle supports USD and US entities only, so there are no multi-currency books or non-US bank feeds. Bank connections are limited to direct integrations with Mercury and Brex, indirect connections through Plaid, or manual upload. If your company is a US entity banking with Mercury, you are covered. If you run a foreign entity or hold accounts in other currencies, Puzzle is not the right fit today.
AI Cowork lets you describe a task in plain English, and an agent prepares the work for your review. Typical jobs are categorizing a batch of Mercury transactions, matching receipts, and setting up revenue recognition schedules. Repeatable work comes from rules: when you finalize a transaction, Puzzle creates a categorization rule automatically, so the same vendor is handled the same way next month. New accounts start below the typical 85 to 90% rate until enough history and rules build up. Nothing changes in your books without your approval. AI Chat is the read-only companion: ask a question and get an answer from your actual books. AI credits apply to those conversational queries, not to the categorization engine.
For digital products billed through Stripe, yes. Puzzle recognizes revenue at the invoice line-item level, tracks customer-level profit and loss, and keeps cash and accrual books side by side, so you see revenue against the cost accounts you categorize. The limits matter: revenue recognition is Stripe-centric, so sales billed elsewhere need manual journal entries. Puzzle is also not built for e-commerce businesses that carry physical inventory.
Puzzle has no inventory module, and that is a permanent product boundary. If you hold physical inventory, you would need to track inventory and cost of goods sold outside Puzzle, and you should not plan around a Shopify order and inventory sync. Software and digital-product startups that bill through Stripe are the strongest fit.
Puzzle does not offer tax services, so tax filing stays with your CPA or tax preparer. What Puzzle can do is get the books ready for them. Catch-up bookkeeping starts at $300 per month of books (11 months behind is $3,300), delivered by a Puzzle bookkeeper or a vetted partner firm working in your Puzzle ledger. Doing it yourself is realistic if you are only a month or two behind and your feeds are connected. If you are further behind, a bookkeeper is usually faster. Timing depends on how many months are missing and how clean the source data is, so confirm a delivery date with your CPA and Puzzle before relying on any deadline.
Puzzle is an AI-native accounting firm, so services run on the same ledger as the software. Expert Reviewed starts at $99/month per entity on top of a software plan: the AI suite does the work, and a bookkeeper reviews, corrects, and closes the books each month, with up to three bookkeeping questions per month. It fits one entity, one accounting basis, and up to $10K in monthly expenses. Full Service starts at $499/month per entity, priced by monthly expenses: a named bookkeeper runs the full monthly close (categorization, reconciliations, accruals and prepaids, financial statements) and answers unlimited bookkeeping questions by email. Your part is small: connect your accounts, answer the occasional question, and approve the month. You see every change. To get started, connect Mercury and your other integrations, then pick the tier that matches your volume.
The shift is from typing entries at month-end to reviewing drafts during the month. As transactions arrive from a feed like Mercury, AI categorizes them, matches receipts, and drafts reconciliations, and an accountant reviews the exceptions. At Puzzle, an AI-native accounting firm, about 90% of transactions are categorized automatically and about 85% are finalized. When the AI is less than 99% confident, it leaves the transaction uncategorized and flags it instead of guessing. You can answer a flagged item in plain English by email, and the AI applies your reply. Every finalization creates a rule, so the same vendor is handled the same way next month. Reviewing the output takes roughly 15 to 20 minutes per week.
One Puzzle customer, Trivium, cut bank reconciliations from 2 hours to 5 minutes, with 81% completed without human intervention.
Two limits to plan for: categorization works at the transaction level, so it will not split a mixed purchase into line items, and a brand-new account starts below the typical 85 to 90% rate until history and rules build up.
The monthly PDF exists because the books were built after the month ended. When AI categorizes and matches transactions to bank activity during the month, the reports can stay live instead. In Puzzle, your cash position, P&L, and balance sheet update daily, and burn rate, runway, and ARR are tracked automatically. Your bookkeeper, whether a Puzzle accountant or a vetted partner firm, works in the same ledger you see, so there is no separate file to send. AI Chat adds a read-only way to ask questions and get answers from your actual books. Humans still review and approve before anything is final, and the cash flow statement reflects cash activity only, not a full indirect-method GAAP cash flow statement. For a Mercury-connected startup, the payoff is simple: you check live numbers any day of the month and use the finalized close for investor reporting.
