Building a SaaS inventory from scratch sounds like a heavy data project. In practice it is a few weeks of focused work that pays for itself many times over. Almost every saving we find for a client, from reclaimed seats to cancelled duplicate tools to a renegotiated renewal, traces back to one thing: a complete and current list of what the organisation actually buys. Without that list, every decision is a guess. With it, the waste becomes obvious.
As an independent, buyer side advisor with no vendor relationship and no commission, our only interest is putting the buyer back in control of the spend. The inventory is where that control begins. This guide walks through where to pull the data, what fields to capture, how to handle the tools nobody approved, and how to keep the list alive once it exists.
Why building a SaaS inventory from scratch pays for itself
Most mid market firms do not know how many software contracts they hold. The common guess is low by a wide margin, because spend hides in three places: the finance system, the corporate cards, and the shadow purchases that never went through procurement. When you build a SaaS inventory from scratch you are really doing one thing, which is dragging all of that spend into a single view where it can be questioned.
The payoff is immediate. Duplicate tools that do the same job sit next to each other for the first time. Renewals that were buried in inboxes get dates against them. Seats nobody uses become countable. None of this is possible while the data lives in ten different places. A good inventory is not the goal in itself, it is the lens that makes every other saving visible. It connects directly to mapping your full digital workplace spend, which takes the raw list and groups it by function so overlaps stand out.
Where to find the data when you start with nothing
You rarely start from zero. The data exists, it is just scattered. Pull from these sources in order and reconcile as you go.
The accounts payable ledger
Start with twelve to eighteen months of accounts payable history. Filter for software vendors and recurring charges. This catches every tool that runs through a proper invoice and a purchase order. It is the cleanest source and usually covers your largest contracts, so it gives you the bulk of the spend fast.
Corporate card and expense reports
The card statements are where the smaller and unsanctioned subscriptions hide. Monthly charges of a few hundred dollars rarely trip any review, so they accumulate quietly. Export the card data, filter for anything that looks like a recurring software charge, and add every match to the list. This is often where the surprises live.
Identity and single sign on logs
If you run single sign on, the login logs show which applications people actually open and how often. This is gold for the inventory because it tells you not just what you buy but what gets used. A tool with a contract but almost no logins is a prime candidate for cancellation. This usage view is the start of quantifying SaaS waste across the stack.
Department interviews
Finish with short conversations across the main teams. Ask each function what tools they rely on and what they pay for outside the central budget. People will name subscriptions that never touched finance or the card programme. These interviews close the gaps the systems miss.
What fields the inventory needs
A list of vendor names is not an inventory. To drive decisions, each row needs enough context to act on. At minimum, capture the following.
| Field | Why it matters |
|---|---|
| Vendor and product | Identifies the tool and surfaces duplicates side by side |
| Business owner | Names who is accountable for the tool and its value |
| Annual cost | Sizes the prize and ranks where to focus effort |
| Licensed seats | The number you pay for |
| Active users | The number who actually use it |
| Renewal date | When the term ends |
| Notice deadline | The last day to act before auto renewal |
| Function or category | Lets you group tools and spot overlap |
| Contract type | Annual, monthly, or multi year, which sets your flexibility |
The gap between licensed seats and active users is the single most valuable column on the sheet. It is where reclaimable money lives, and you cannot see it until both numbers sit in the same row. The notice deadline matters almost as much, because a tool you want to drop still costs you a full term if you miss the window. Pairing the inventory with a SaaS renewal calendar turns those dates into action.
Handling shadow IT without a witch hunt
The inventory will expose tools that nobody formally approved. The instinct is to clamp down, but that is the wrong first move. Shadow purchases usually exist because a team had a real need and the official process was too slow. Treat each discovery as information, not as a fault. Record it, understand why it was bought, and decide whether it should be kept, consolidated, or cut. A blame free first pass gets you honest data. A heavy handed one drives the next round of spend further underground.
From raw list to a working register
Once the data is in, the inventory becomes a working register rather than a one off audit. Sort by annual cost to find the contracts worth your attention. Flag every case where active users sit well below licensed seats. Group tools by function and look hard at any category with three or more overlapping products. This is the moment the spreadsheet starts paying for itself, because the first wave of savings is usually sitting in plain view: a duplicate tool, a block of dormant seats, a renewal three weeks from locking in.
The question of who keeps this register current matters as much as building it. A list that drifts out of date within a quarter is worth little. Assigning a single named owner, as covered in our guide on who owns SaaS spend in the enterprise, is what keeps the inventory trustworthy over time.
Spreadsheet or platform
You do not need to buy software to build software visibility. A well structured spreadsheet handles most mid market stacks comfortably, and the discipline of keeping it current matters far more than the tool. A dedicated SaaS management platform earns its place once the stack grows past a hundred or so applications, when contracts change often, or when you want usage data flowing in automatically. Until then, the spreadsheet plus a monthly review delivers the great majority of the value at no extra cost.
How long it takes
For a typical mid market firm, a usable first version of the inventory takes two to four weeks of part time effort. The accounts payable pull is a day. The card reconciliation is a few days. The interviews and the usage data take the rest. You do not need a perfect register before you start finding savings. The first complete pass almost always surfaces enough waste to fund the whole exercise, and the list keeps earning its keep every renewal cycle after that.