This is the step-by-step setup most new sellers don't get from their first bookkeeper or their first accounting software. It assumes you're starting fresh or restructuring a setup that's already showing strain. The goal: a books structure that scales from one marketplace to five without rework.
QuickBooks Online, QuickBooks Desktop, or Xero. These are the three platforms ecommerce sellers actually use. Pick one before you pick anything else, because every integration and every bookkeeper decision flows from this choice.
Three quick decision rules. If your accountant has been doing your books for years, pick the platform they prefer. If you're choosing fresh and sell mostly through marketplaces, QuickBooks Online is the safest default in the US. If you're operating across US, UK, and EU markets, Xero handles multi-currency more cleanly. If you have a legacy desktop setup or a CPA who insists on Desktop, ConnectBooks supports it. Don't burn cycles re-evaluating later.
This is the single most important decision in the setup. The chart of accounts is the structure your reports filter on. Build it wrong and you can't answer the question "which channel makes me money" without exporting to a spreadsheet every month.
The base structure most ecommerce CPAs recommend:
The mistake most sellers make is one combined "Sales" account that mixes all channels, and one combined "Marketplace fees" account that mixes referral fees with advertising with fulfillment. Both are easy to set up. Both make per-channel and per-category analysis impossible without rework.
Accrual. Not cash. The timing differences between order date and settlement date create real accounting impact for ecommerce, and any inventory-carrying business is better served by accrual. Cash accounting is permitted by the IRS for businesses under $27M in revenue (2025 threshold), but the resulting books make management decisions harder.
If your bookkeeper proposes cash to "keep it simple," push back. The complexity goes somewhere: either into your accounting structure or into your decisions. Better there than in your year-end tax planning.
The integration order matters. Connect them backwards and you'll spend weeks reconciling duplicate entries.
Decide between FIFO and weighted average before you have meaningful inventory layers. Switching later is allowed but requires a clean cutover and CPA documentation.
For most ecommerce sellers, FIFO is the right answer. It matches the physical flow of inventory, it produces more accurate margin reporting when costs are rising (tariffs, freight increases), and it's the default in most accounting software. Weighted average is simpler but obscures cost trends.
Most US marketplaces are facilitators now. They collect and remit sales tax on your behalf for orders shipping to states where marketplace facilitator laws apply. That tax flows through your books as collected revenue and remitted liability, netting to zero. You don't file on those sales.
What you do file on: direct DTC sales (Shopify own checkout, your own site) into states where you have nexus. Register, collect, file, remit. Start with the states where you have warehouse inventory (Amazon FBA states, your 3PL state, your home state) and add states as you cross economic nexus thresholds (typically $100K in annual sales or 200 transactions).
Monthly close by the tenth of the following month. Earlier is better. Weekly reconciliation of each settlement, monthly formal close, quarterly financial statement review with your accountant.
Multi-marketplace operations have enough complexity that letting two months drift past close turns into a forty-hour cleanup project. The discipline of a tenth-of-the-month close prevents that compounding.
ConnectBooks automates the work this guide describes. Settlement reconciliation across Amazon, Shopify, Walmart, eBay, and TikTok Shop. FIFO COGS applied per SKU. Marketplace-facilitator sales tax handled correctly. ConnectStock for multi-location inventory. Crunch, the AI CFO, in active beta on Diamond and Platinum tiers, answering business questions about your numbers in plain English. Plans start at $149/month for Gold and scale through Diamond and Platinum based on order volume and the depth you need.
From kickoff to first clean monthly close, roughly two to four weeks for a single-marketplace operation, four to six weeks for multi-marketplace. The bulk of the time is data validation, not configuration.
For a single-marketplace operation under $500K annual revenue, you can run this yourself with the software handling reconciliation. Past that, a part-time bookkeeper for review and month-end close is the right structure.
A chart of accounts that doesn't split revenue and expenses by channel. Restructuring the chart of accounts later requires reclassifying every historical transaction, which is a multi-week project for any operation past its first year.
Yes, but it requires Form 3115 with the IRS and meaningful bookkeeping work to restate the books. Easier to start accrual from day one.
Get the setup right the first time. Start a 30-day free trial of ConnectBooks and we'll help with the chart of accounts, the integrations, and the first monthly close. No credit card required to start.
Running an e-commerce business comes with plenty of challenges, but ConnectBooks is here to make your life easier. With real-time insights, seamless integrations, and detailed tracking of your profitability and inventory, you can stay ahead of the game. Whether you’re selling on Amazon, Shopify, Walmart, TikTok or eBay, ConnectBooks helps you manage your finances with 100% accuracy and confidence, so you can focus on growing your business.
Ready to level up? Start making smarter, data-driven decisions every step of the way. Try ConnectBooks Free Today or Schedule a Demo
