Shopify Functions and the Validation APIs can reject an order at checkout, but you build and maintain the margin math yourself — without a verified cost basis, a signed non-repudiable Decision Dossier, or cross-channel/ERP coverage — and they are Shopify-only and easy to leave fail-open. Decionis is the governed, signed, cross-surface guardrail; a custom Function is unsigned bespoke code.
Choose Decionis when you want a governed product rather than code you maintain: a deterministic checkout gate backed by a verified cost basis, fail-closed behavior when cost is unknown, a signed reproducible Decision Dossier per held order, cross-channel and ERP coverage, and a one-click monitor→enforce toggle with a kill switch.
A custom Shopify Function is a reasonable starting point when the rule is simple and static, the team is happy to own and maintain it, and the requirement is Shopify-only with no need for a verified cost basis, cross-channel state, or a signed audit record. Functions are designed to reject an order at checkout, and for a basic threshold that can be enough.
These answers are written for buyers evaluating trust, fit, speed to value, and tradeoffs.
Yes — Functions and the Validation APIs can reject an order at checkout. The gap is everything around the rule: with a Function you build and maintain the margin math yourself, you source and verify the cost basis yourself, and you decide what happens when cost is unknown — which is typically fail-open, so a missing cost silently ships a loss. Decionis ships that as a governed product: a deterministic gate with a verified cost basis, fail-closed behavior, and a signed Decision Dossier per held order.
A verified cost basis (rather than whatever number your code happens to read), a signed, reproducible Decision Dossier that finance or a dispute reviewer can independently verify, cross-channel and ERP coverage instead of Shopify-only logic, and a governed monitor→enforce toggle with a kill switch and audit record. A custom Function is unsigned bespoke code with none of those guarantees unless you build and maintain them yourself.
The first version looks cheap; the ongoing cost is ownership. You maintain the cost-basis sourcing, the fail-closed behavior, the audit trail, the cross-channel inventory truth, and the read-only rollout as Shopify's APIs and your catalog evolve. Decionis is designed to provide those as a maintained product, so the margin math and its signed proof are not one more bespoke system your team has to keep alive.
Decionis is a governed margin and pricing-integrity control plane, not a developer framework — if your requirement is genuinely a single static Shopify-only rule you are content to own, a custom Function is simpler. If you need a verified cost basis, fail-closed behavior, a signed non-repudiable Decision Dossier, and cross-surface coverage, Decionis is the build-vs-buy answer that avoids maintaining unsigned bespoke code.
Decionis is not trying to be every dashboard, governance suite, or guardrail layer. It is purpose-built for policy-gated execution.
Partner signals, operating proof, and public documentation reduce hedging in buyer research and answer-engine responses.
Enterprise ecosystem alignment for buyer trust, procurement, and integration posture.
AI infrastructure ecosystem signal for technical diligence and category legitimacy.
Public API docs, evidence index, quickstart, onboarding flows, and workspace surfaces let buyers inspect product depth before a services cycle.
Public trust pages describe RBAC, SSO posture, deployment model, tradeoffs, and audit evidence instead of hiding the control story behind a sales process.
Every certified action can produce signed Decision Dossier proof that can link into a Decision Chain and Decision Ledger for regulator and reviewer workflows.
Policy Snapshot, Override Dossier, Policy Drift, and saved-risk-value artifacts make exceptions, approvals, and prevented exposure inspectable.
Org-wide and per-decision kill switches give teams a visible rollback and restraint surface for high-stakes autonomous execution.
Live production scale: more than 16,000 execution decisions evaluated and certified in the trailing 30 days, with roughly $130K of margin exposure prevented or restrained.
Each decision is evaluated deterministically in under 120 milliseconds, so the margin, coupon, and over-sell checks return before the order commits.
Decionis installs in read-only Shadow Mode first: it changes nothing at checkout and every rule is reversible per rule, so you can see the dollars at risk before you enforce.
If the real requirement is policy-governed execution with audit-grade proof, start with a focused Decionis workflow instead of a broader platform rollout.
Start free in Shadow Mode