How do I make sure purchases reference the contract pricing we negotiated?

Contract compliance is the degree to which actual purchasing follows the contracts you negotiated - buying from the contracted vendor, at the contracted price, on the contracted terms. Contract leakage is the gap: spend that goes off-contract (a different vendor, list price instead of the negotiated discount, terms that drifted) and quietly erodes the savings the contract was supposed to deliver. Leakage is usually invisible because each off-contract purchase looks fine in isolation; you only see it by comparing actual spend against contract terms in aggregate. The discipline that prevents it is making the contract the default path - steering buyers to contracted vendors and validating invoice rates against the rate card - so going off-contract takes deliberate effort rather than being the easy default.

Validate invoiced rates against the contract rate card at matching, not at year-end. If the system compares each invoice line's price to the agreed price, an invoice billed at list instead of the negotiated rate surfaces as an exception before it pays - the moment to catch it is when the money is on the line, not in a quarterly review. Operationally that requires the contract's rates to be accessible during matching (in a maintained repository or carried on the PO), and a tolerance that flags meaningful price gaps. The structural fix is to anchor purchasing to the contracted price upfront - when the PO carries the negotiated rate, the invoice has something correct to match against instead of being checked against nothing.

Reference the governing contract on the PO and default the contracted vendor and rates into the request/PO so the contracted path is the default. When choosing the on-contract option is the easiest path, compliance becomes the lazy choice rather than a discipline.

Aggregate actual spend per contracted vendor against the contract's committed minimum or volume-discount tiers, and monitor progress through the term. Missing a volume tier because nobody tracked cumulative spend is leakage in reverse - paying for a discount you didn't capture.

Maintain contract end and notice dates in a repository with reminders well ahead of the auto-renew window, routed to the owner. Auto-renewals that slip by unexamined are how stale pricing and unwanted subscriptions persist.

Compare each invoice line's price to the contracted rate at match time and flag deviations beyond tolerance as exceptions. This requires the rate card to be available during matching - the practical prerequisite for catching price violations before payment.

AI can compare invoiced prices and terms against contract rate cards and surface likely overbilling for human review, accelerating what's otherwise a manual audit. The review and recovery decision stays with finance; treat it as detection assistance, not automated dispute resolution.

Ownership varies (often legal holds the executed contract, procurement/finance own the commercial terms), but the operational requirement is that purchasing and AP can access the terms that govern a buy - vendor, rates, dates, minimums. A repository nobody can reach at purchase time prevents compliance.

Track contract status per vendor and flag (or gate) new purchases against vendors whose contracts have lapsed, so off-contract spend on expired terms surfaces before it happens. Expired-contract purchasing is contract leakage with extra risk.

Stampli's position is that spend control should start before the invoice arrives. When requests, approvals, purchase orders, invoices, and payments stay connected, finance can manage policy, coding, and evidence as one workflow instead of reconstructing the story after the fact.