{"product_id":"purchase-approval-routing-with-postgres-email-webhook","title":"Purchase Approval Routing with Postgres, Email \u0026 Webhook","description":"\u003ch3\u003eAutomated Purchase Approval Routing with Postgres + Email + Webhooks\u003c\/h3\u003e\n\u003cp\u003eThis n8n workflow automatically receives purchase requests via \u003cstrong\u003ewebhook\u003c\/strong\u003e, evaluates them against spend tiers, department budget status, and vendor risk stored in \u003cstrong\u003ePostgres\u003c\/strong\u003e, then either \u003cstrong\u003eauto-approves\u003c\/strong\u003e, \u003cstrong\u003erejects\u003c\/strong\u003e, or runs a \u003cstrong\u003esequential email approval chain\u003c\/strong\u003e—with final notifications sent to the requester and an audit message posted to \u003cstrong\u003eSlack\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReceives \u0026amp; validates requests:\u003c\/strong\u003e Accepts a purchase request via a POST webhook, validates required fields, and normalizes currency amounts to \u003cstrong\u003eUSD\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLoads decision inputs from Postgres:\u003c\/strong\u003e Retrieves vendor risk\/approval status, department budget and manager details, and the \u003cstrong\u003elast 30 days of spend\u003c\/strong\u003e with the same vendor.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplies policy rules:\u003c\/strong\u003e Uses spend tiers (including cumulative 30-day vendor spend), budget limits, self-approval avoidance, and vendor risk checks to determine whether to approve, reject, or require specific approval levels.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCreates a pending record:\u003c\/strong\u003e Saves the request as pending in Postgres and immediately responds to the webhook caller with the \u003cstrong\u003erequest ID\u003c\/strong\u003e, \u003cstrong\u003ecurrent status\u003c\/strong\u003e, and \u003cstrong\u003erequired approvers\u003c\/strong\u003e.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRuns sequential approvals (if needed):\u003c\/strong\u003e Sends an approval email with approve\/reject links, waits for responses, and continues the chain with reminders until completion or expiry.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFinalizes \u0026amp; audits:\u003c\/strong\u003e On approval, records the decision in Postgres, generates a \u003cstrong\u003ePO number\u003c\/strong\u003e, commits budget, emails the requester, and posts an \u003cstrong\u003eaudit notification to Slack\u003c\/strong\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eCentralizing purchase order approval routing for SaaS teams with consistent spend-tier governance.\u003c\/li\u003e\n  \u003cli\u003eReducing bottlenecks by auto-approving low-risk requests and escalating higher-risk ones.\u003c\/li\u003e\n  \u003cli\u003eAuditable approval trails for vendor spend and department budget usage over rolling 30-day windows.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIntegrations:\u003c\/strong\u003e \u003cstrong\u003ePostgres\u003c\/strong\u003e (vendors, departments, requests, audit logs), \u003cstrong\u003eEmail\u003c\/strong\u003e, \u003cstrong\u003eSlack\u003c\/strong\u003e, and a \u003cstrong\u003eWebhook\u003c\/strong\u003e endpoint.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003en8n nodes\/logic used:\u003c\/strong\u003e \u003cem\u003eif, set, code, wait, switch, webhook\u003c\/em\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003ePerfect for n8n users and automation engineers who need production-ready purchase approval workflows with Postgres-backed policy enforcement.\u003c\/p\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":46172943450291,"sku":"N8N-20587","price":17.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/NJdQe6S5m1G-1GDI577oF_vlZsuX7m.png?v=1791364351","url":"https:\/\/buyflowscripts.com\/products\/purchase-approval-routing-with-postgres-email-webhook","provider":"N8N Commerce","version":"1.0","type":"link"}