Why I Built SKU.io: A Founder Q&A With Kalvin Mizzi
I’ve run my own e-commerce business since 2008, and SKU.io started as the system I built to run it. These are my answers to the questions I get asked most about where it came from, what it does differently, and where it’s going.
Who is Kalvin Mizzi, and what is SKU.io?
I’m Kalvin Mizzi, the founder of SKU.io. I taught myself to code as a teenager and was building online stores for clients by 1996. In 2008 I started my own e-commerce business, reselling branded auto and powersports parts on eBay, Amazon, Shopify, Walmart and our own sites. That business still runs today, and it runs on SKU.io.
SKU.io is the back office for multi-channel e-commerce brands. It keeps one inventory ledger for every warehouse, 3PL and sales channel, and pushes stock to the channels so you don’t oversell. It also handles purchasing, sales orders, fulfillment, manufacturing and bills of materials, Amazon FBA, wholesale and EDI. On top of that it tracks landed cost, so you can see the true profit on every order and the numbers match your accounting software.
Our customers are mostly brands doing roughly $1M to $50M a year across several channels. Many of them come to us after a sync tool or an ERP let them down. I still give every demo myself, and I’m involved in every onboarding.
Why did you build SKU.io?
I built it because I needed it. When I started my e-commerce business in 2008, I spent the first few months stitching together different services, and none of them could run a multi-channel operation properly. Within the first year I started building our own internal system for inventory, purchasing, listings and accounting.
We ran the business on that system for about ten years. The pain that drove it was simple: my numbers never matched. Stock counts disagreed between channels, and the profit in my operations software never matched my accounting software. If you can’t trust the numbers, you can’t run the business by them.
By 2019 the cost of maintaining software for a single user had become too high. I had developers on staff just to keep our own system going, and only we benefited. I looked at the market again and still wasn’t happy with anything. So I put the question to my Entrepreneurs’ Organization forum: abandon it and move to a competitor, keep going as we were, or turn it into a product for other sellers. I chose to build a SaaS.
We rewrote it from scratch, with none of the old code, but with ten years of lessons about how e-commerce operations really work. The first outside customer went live in 2021.
How is SKU.io different from other inventory and ERP software?
Three things set us apart.
First, speed. When a customer reports a bug, we usually fix it the same day or the next. When they need a workflow we don’t support, we build it, often in days. Many of the sellers who switch to us were told elsewhere that their request was “on the roadmap” for months. I call us software with a service: we solve the business problem, instead of handing over software to take or leave.
Second, we are operators. We have run our own e-commerce business since 2008, on this software. When a customer describes a problem, I have usually lived it. That shows in the everyday workflows. Older ERPs treat e-commerce as an add-on, and the simple daily tasks end up complicated.
Third, numbers you can trust. Every unit movement is an entry in a perpetual ledger you can audit, and costs follow each unit from the purchase order to the sale. When a number looks wrong, you click through to the source document instead of re-syncing and hoping.
For customers, that means fewer spreadsheets, no overselling, and knowing which orders and products actually make money. We charge no onboarding fee and work month to month, so the risk of switching stays low.
Which businesses is SKU.io built for?
We focus on product brands that sell physical goods across several channels, usually some mix of Shopify, Amazon, Walmart, TikTok Shop, eBay and wholesale. In size, most are between about $1M and $50M a year in revenue.
Within that, we serve consumer goods of many kinds: beauty and personal care, apparel and fashion, food and beverage, home goods, supplements, hobby and outdoor products, and auto and powersports parts, which is where our own business sells. We also support brands that make their own product, with bills of materials, manufacturing orders and lot and expiry tracking, and brands that sell wholesale to retailers through EDI.
The brands that get the most out of SKU.io have three things in common. They sell on more than one channel, so keeping stock in sync is a daily risk. They hold inventory in more than one place, such as a 3PL, Amazon FBA and their own warehouse. And they have outgrown spreadsheets but don’t want an enterprise ERP that takes a year to implement.
We are honest about fit, too. A small single-channel shop is usually better served by something simpler and cheaper, and we will say so.
Which SKU.io features stand out?
Most inventory tools stop at stock counts. The features our customers tell us they couldn’t find elsewhere are the ones built around money and proof.
True profit on every order. SKU.io carries landed cost (freight, duties, marketplace fees and shipping) down to each unit through FIFO cost layers, so every order shows its real margin. Any number can be traced back, click by click, to the purchase order or invoice behind it, and the totals match the accounting software. A sale at a loss raises an alert the same day. In my own business we run dozens of these alerts.
Inventory you can audit. Every movement is an entry in a ledger, and an automated check runs every hour to confirm that stock, costs and channel quantities still agree. If they drift, we know before the customer does.
Amazon in depth. We reconcile Amazon’s FBA inventory ledger against our own, flag discrepancies for reimbursement claims, and bring removal orders back into stock at their real unit cost.
The awkward workflows. Vendor deposits on purchase orders, consignment stock and multi-level bills of materials. These are the cases buyers are often told no system handles.
Run it from an AI agent, if you want. Beyond a full API and an MCP server, we publish agent skills that teach an agent like Claude both our API and the operating practices behind it. Some customers run daily operations from a terminal and open the app only for reports.
Is SKU.io worth what it costs?
I judge it as a seller, because I am one: does it pay for itself?
Margin first. Most brands know their revenue by product, but not what each product actually earns. SKU.io attributes the real costs to every unit: freight and duties, marketplace and payment fees, shipping and returns. That gives a true contribution margin by product, channel and order, which is where hidden losses show up. In my own business we had helmets that looked like a 75% margin until the returns from sizing and colors were counted against them. Customers find the same: a fee quietly eating one channel, or a best seller that loses money after shipping.
Then time. Work that used to take people hours every week, like building purchase orders, reconciling 3PL and Amazon inventory, or keeping stock in sync, now runs inside SKU.io. Because the system is open to AI agents, an agent can take on much of what’s left, such as turning a supplier’s price sheet into catalog entries. Those hours go back into building the brand and growing sales.
Then the tools it replaces. We solve business problems rather than hand over take-it-or-leave-it software, so each one we solve tends to retire another subscription: an inventory sync app, a forecasting tool, a profit dashboard, a reconciliation spreadsheet. We keep widening what an ERP covers, and we’re now building PPC management and content publishing into SKU.io as well.
There is no onboarding fee, terms are month to month, and pricing scales with order volume and product count.
How does SKU.io keep up with new technology and AI?
Most of our roadmap comes from customers. We keep a close working relationship with each one, and when they hit a gap we usually close it within days. Each improvement goes into the product, so the next customer benefits too.
The second source is my own business. We still run our e-commerce company on SKU.io, so when a marketplace changes its rules or a new channel matters, we feel it ourselves. New channels like TikTok Shop and Walmart’s fulfillment services were added that way.
On technology, AI has changed how we work more than anything in the last decade. We build heavily with AI coding agents, and much of the codebase has been rewritten since 2023. That is a big reason we can ship what used to take months in days. It has also changed what customers want. Some of them now run their operations mostly from an AI agent in a terminal and only open the app to look at reports. We designed SKU.io API-first from the beginning, years before this, and that design has aged well. We now publish an MCP server and a library of agent skills, which teach an AI agent both the API and the business practices behind it.
We keep the discipline that matters most: real testing and careful review before anything ships.
What is an agentic e-commerce operating system, and where is SKU.io going?
I think the word ERP is out of date. In ten years I see SKU.io as an agentic e-commerce operating system: the part of a company that runs the e-commerce operation, with much of the work done by AI agents.
The bigger shift is that companies are starting to build their own AI HQ: a private portal, and an AI brain that knows the business. We think that’s the right instinct, and we want to fit it, not fight it. Keep your portal, and keep the sensitive things in it: strategy, people, finances, decisions. Then connect it to SKU.io for everything e-commerce. Your agents ask us what to reorder, why a channel’s margin dropped or where a shipment is, and we do the work behind the answer.
Our vision is to take care of the headaches that would otherwise eat into an e-commerce CEO’s time: stock that doesn’t match, a 3PL that miscounts, a fee nobody noticed, purchase orders that need chasing. Those become our problem instead of theirs.
For that to work, the system underneath has to be trustworthy. The ledger has to be exact, every number has to trace back to its source, and every action has to be possible through an API. That has been our foundation from the start. From here we’ll keep deepening our agent skills, so an agent works with the judgment of an experienced operator, and keep going further into cost control and profitability.
Through all of it, we’ll stay a company run by e-commerce operators.
Does SKU.io work on mobile?
SKU.io is a web app, and our goal is that every part of it works properly on a phone. We are working through it section by section, and new screens are now checked on phone layouts before they ship. The reason is personal. I often want to check something from my phone, such as a stock level, an order or a purchase order, and I want that to be as easy as it is at a desk.
In the warehouse, the picking screen is built to work on a phone, and stock counts and receiving work with barcode scanners. We built those because our customers’ teams work on their feet, not at desks.
The bigger change in mobile, I think, is AI. Because everything in SKU.io is available through our API and MCP server, an operator can connect an AI assistant to their account and ask it questions or give it tasks from anywhere. Asking “what do I need to reorder this week?” from a phone and getting an answer from live data is often more useful than a smaller version of a big screen.
A native app in the app stores is something we’ll consider once the responsive site is complete. For now we’d rather make every page work well in a phone browser.
How does SKU.io handle data integrity, security and compliance?
For an inventory and accounting system, integrity starts with the data. Every stock movement is a recorded event in a ledger, never an overwritten number. Automated checks run every hour to make sure inventory, costs and channel stock are all in balance. If anything goes out of balance, we’re alerted and fix it right away. Every change to a record is logged with who made it, when, and the old and new values.
On security, every customer has their own separate database. All traffic is encrypted in transit, and backups are encrypted and kept with a separate provider in a separate facility. Access is role based, and the same permissions apply to the screens and the API. Every user can turn on two-factor login. Because we hold Amazon Selling Partner data, we pass Amazon’s security assessment every year. It is administered externally and covers encryption, access control, incident response and data retention. Customer personal data from the marketplaces is redacted on a schedule once it’s no longer needed.
We’re open about what we don’t have. We are not SOC 2 certified today, and we’ll pursue it when our customers need it. Customers own their data, can export it at any time, and can reach all of it through the API.
How does SKU.io work with its customers?
It starts before the sale. I give every demo myself, usually on the prospect’s own workflow, and I tell people plainly when we’re not the right fit. Starting a relationship on an honest answer is worth more than a signature.
During onboarding we work very closely. Each customer gets a shared Slack channel with the people who build the software, and we’re in it every day. We bring over their data, reconcile the numbers with them before they switch, and record our calls so they have a library to train their team. Onboarding often uncovers problems in a brand’s data that nobody knew were there, and working through those together builds a lot of trust.
After go-live, support moves to tickets. Bugs are usually fixed within a day, and requested features often ship within days. When a customer asks for something, they hear back from someone who can actually change the software, not an account manager reading from a script.
We also work month to month, with no long contracts. That keeps us honest. A customer stays because the product and the service are earning it, and that’s how I want it. Many of our customers have referred other brands to us, and that’s how most of our growth has come.
What was the hardest part of building SKU.io?
The biggest challenge was building a complex product for years without outside money. When I decided in 2019 to turn our internal system into SaaS, I funded it from the profits of my e-commerce business. It took about two years to reach the first customer, and years more of losing money while we made the product good enough to stand next to systems built by much larger companies. Building software that works for many different businesses turned out to be far harder than building it for one.
For a long time I also kept nearly all my attention on the product, and I put off spending on marketing because the company wasn’t making money yet. Eventually I accepted that a good product doesn’t sell itself. You have to bring it to market, and that’s an investment, not a cost.
Two things got us through. The first was customers. Our earliest ones came from an e-commerce founders’ community I belong to, and they referred others. Their feedback shaped the product more than any plan could. The second was AI. From 2025 our development speed rose sharply, and a backlog that once ran to hundreds of items came down to a few dozen.
Today SKU.io is profitable and growing, still self-funded, and still run by the people who built it.
For the full timeline, see our story, and for what we believe, why SKU.io exists. If any of this sounds like your operation, book a demo and I’ll walk you through it on your own data.