Business approval workflows

Approval Workflows

When to Use

Use when implementing business or security approval flows—such as discount/quote approvals, purchase orders, refunds/payouts, role elevations, or sensitive production operations.

Core Principle: An Approval Is Bound to a Specific Version & Payload

An approval is never a blank check on a mutable record. If Sales Rep A gets approval for a 5% discount on Quote #104 and then edits Quote #104 to a 40% discount before converting it to an order, an unbound status = 'approved' flag allows fraud!

1. Payload Hash & Revision Binding

Every approval_requests and approval_decisions record must bind to the exact state of the subject:

• Subject Version & Canonical Snapshot Hash:
  • Compute a deterministic digest (subject_version + payload_sha256 over the canonicalized approval-relevant fields: line items, unit prices, discount, currency, counterparty, terms).
  • Freeze the subject record against direct edits while status = 'pending_approval' or 'approved'.
  • Re-Approval Trigger Rule: If any material field covered by payload_sha256 is modified (or if the price/discount moves in a risk-increasing direction), automatically transition the record back to draft / pending_approval and mark prior approvals superseded.

2. Separation of Duties (SoD) & Conflict-of-Interest Rules

Enforce SoD invariants at the database/service boundary:

1. No Self-Approval: decision.approver_id !== request.requester_id AND decision.approver_id !== resource.created_by_id AND decision.approver_id !== resource.owner_id (unless an explicit, documented single-owner workspace exception is configured).
2. Distinct Multi-Approver Quorum (Four-Eyes / $M$-of-$N$): When a high-value threshold requires 2 approvals (e.g., Sales Director + Finance Controller), the same person holding both roles cannot sign off on both steps (COUNT(DISTINCT approver_id) >= required_approvers).

3. Tiered Thresholds & Sequential / Parallel Routing

Model threshold rules declaratively:

• Tier 1 (discount <= 10% and total <= 10,000): Auto-approved (no_approval_required).
• Tier 2 (discount <= 25% or total <= 50,000): Requires sales_manager of the rep's department.
• Tier 3 (discount > 25% or total > 50,000): Sequential approval—Step 1: sales_manager, Step 2: finance_director.

4. Expiration & Execution Re-Verification

• Attach an expires_at timestamp to approvals where business validity is time-sensitive (e.g., quote price lock or temporary payout sign-off).
• At execution time (converting the approved quote to an order or disbursing funds), atomically verify in a single transaction that approval.status === 'approved', approval.payload_sha256 === currentPayloadHash(resource), and approval.expires_at > NOW().