CPA & advisory for online sellers
Know your numbers.
Scale your store.
Clean, automated books built for multi-marketplace selling — Amazon, Shopify, Walmart and TikTok Shop reconciled correctly, sales tax handled across every state you sell in, and advisory from someone who actually knows your business.
The multi-channel stall
Selling online is easy to start.
Hard to keep clean.
01
Marketplace payouts don't match your books
Fees, FBA reimbursements, refunds and multi-currency sales land as one lump deposit — and quietly hide what your business is really earning.
02
Sales tax became a liability you can't see
03
You don't know your true margin by SKU
04
Your numbers are always three months late
The advisory system
Five things I get right.
One clear picture.
01
Clean Books & Cloud Setup
Bookkeeping & cloud accounting
02
Marketplace & Systems Integration
App stack & integrations
03
Multi-State Sales Tax
Sales tax & nexus
04
Tax Strategy & Entity Structure
Planning & structuring
05
Scaling & Exit-Readiness
Advisory as you scale
Marketplace accounting
This is not regular bookkeeping.
What online sellers actually need
- Marketplace fees, FBA reimbursements and refunds reconciled correctly
- Inventory and COGS tracked at the SKU level, not in aggregate
- Multi-currency sales converted and recorded properly
- Sales-tax nexus monitored state by state, continuously
- Books that close fast enough to support a real decision
- Numbers that are current — not three months out of date
What The Online Seller CPA delivers
- A2X / Link My Books integration built and maintained for you
- SKU-level unit economics after ads and marketplace fees
- Proactive registrations before a filing is ever overdue
- Entity and S-Corp structuring that protects and optimizes
- A monthly close you can trust the first time you look
- Advisory timed to the week you actually need the answer
Who this is built for
Your store has traction. Now it needs operating discipline.
Shopify DTC
Single-founder brands doing seven figures who need books they can trust.
Amazon & FBA
Sellers whose payouts and fees never quite reconcile on their own.
Multi-marketplace
Walmart, TikTok Shop and beyond — a channel portfolio, not one bet.
Multi-brand
Operators running several brands who need structure and protection.
The origin story
Not an overnight pivot. Built one client at a time.
Off desktop, onto the cloud
I opened my practice to move owners off outdated bookkeeping — rebuilding charts of accounts, migrating history, and teaching owners to read their own numbers. The value was never the software; it was the visibility.
Amazon & Shopify change everything
A new generation launched on marketplaces with needs traditional bookkeeping wasn't built for — sales across channels, inventory in fulfillment centers, and a tax landscape reshaped by Wayfair. I went all in.
A practice built entirely on retail
Deep technical capability in marketplace accounting paired with real tax and advisory expertise — from founders shipping their first hundred units to brands doing eight and nine figures.
Licensed CPAFounder-led advisory
No portfolio of anonymous accounts. I know every business I work with.
For more than fifteen years I’ve built my career as a CPA — the last six devoted entirely to online retail. I pair the discipline of a CPA with the pattern-recognition of someone who’s seen hundreds of e-commerce businesses up close, turning transaction-level data into insight you can actually act on.
Oren GulasaFounder · The Online Seller CPA
In his words
"I know the businesses I work with — their products, their margins, and where they're headed. That's the standard I hold myself to."
Lessons learned
What six years and 200+ online sellers taught me.
Marketplaces aren't a monolith anymore
It used to be all Amazon. Now it's Amazon, Shopify DTC, Walmart, TikTok Shop, and whatever's next. The best sellers treat channels as a portfolio and build books flexible enough to absorb a new one overnight.
Sales tax keeps getting harder, not easier
Since Wayfair, nexus thresholds and facilitator rules keep shifting. What was compliant last year isn't guaranteed this year — the most common blind spot I see, even among sellers who assume the marketplace handles it.
AI is changing the back office, not judgment
Reconciliation and forecasting are getting automated — a good thing. But the calls that move a business still need someone who understands it. AI gives sellers better information, not better instincts.
Protecting the brand matters as much as the numbers
I've watched suspensions, hijacked listings and IP disputes end businesses overnight — no matter how clean the books were. Account protection belongs in the conversation from day one, with Seller Protected.
The winners obsess over unit economics
Revenue is vanity until you know true margin by SKU, after ads and fees. The brands that scaled from six to eight figures without blowing up cash flow knew their numbers cold — long before they were forced to.
The best advice comes from a real relationship
It's not the fanciest dashboard that helps most — it's someone who knows your business well enough to say "that number looks off" before it's a problem. Data tells you what happened; a relationship turns it into the next move.
Interactive growth diagnostic
Find the first constraint to fix.
Three answers. One logical starting point.
Choose one option in each question and your result will show where we'd begin.
Let's connect
Ready to talk about
your numbers?
I work with a limited roster of clients by design — personal attention is the point. Whether you’re figuring out your first steps or want a second opinion on your numbers, I’d like to hear from you. I read every message myself.
Real, focused advice on your business.
This isn't a free call — it's real advice. And if you sign on as a client afterward, the full session fee is credited toward your services.