This workflow follows the HTTP Request → Postgres recipe pattern — see all workflows that pair these two integrations.
The workflow JSON
Copy or download the full n8n JSON below. Paste it into a new n8n workflow, add your credentials, activate. Full import guide →
{
"name": "Contracts Module",
"nodes": [
{
"parameters": {
"httpMethod": "POST",
"path": "contracts/create",
"options": {}
},
"name": "Create Contract Webhook",
"type": "n8n-nodes-base.webhook",
"typeVersion": 1,
"position": [
250,
300
]
},
{
"parameters": {
"functionCode": "// Extract contract data\nconst data = $input.item.json.body;\n\n// Validate required fields\nif (!data.unit_id || !data.tenant_id || !data.start_date || !data.end_date || !data.monthly_rent || !data.security_deposit) {\n return {\n error: true,\n message: \"Missing required fields: unit_id, tenant_id, start_date, end_date, monthly_rent, and security_deposit are required\"\n };\n}\n\n// Set default values if not provided\ndata.status = data.status || 'active';\n\nreturn {\n data,\n error: false\n};"
},
"name": "Validate Contract",
"type": "n8n-nodes-base.function",
"typeVersion": 1,
"position": [
450,
300
]
},
{
"parameters": {
"conditions": {
"string": [
{
"value1": "={{$json[\"error\"]}}",
"operation": "equal",
"value2": "true"
}
]
}
},
"name": "Validation Check",
"type": "n8n-nodes-base.if",
"typeVersion": 1,
"position": [
650,
300
]
},
{
"parameters": {
"respondWith": "json",
"responseCode": 400,
"responseData": "={{$json[\"message\"]}}",
"options": {}
},
"name": "Error Response",
"type": "n8n-nodes-base.respondToWebhook",
"typeVersion": 1,
"position": [
850,
200
]
},
{
"parameters": {
"operation": "executeQuery",
"query": "INSERT INTO leases (unit_id, tenant_id, start_date, end_date, monthly_rent, security_deposit, status)\nVALUES ('{{$node[\"Validate Contract\"].json[\"data\"][\"unit_id\"]}}', '{{$node[\"Validate Contract\"].json[\"data\"][\"tenant_id\"]}}', '{{$node[\"Validate Contract\"].json[\"data\"][\"start_date\"]}}', '{{$node[\"Validate Contract\"].json[\"data\"][\"end_date\"]}}', {{$node[\"Validate Contract\"].json[\"data\"][\"monthly_rent\"]}}, {{$node[\"Validate Contract\"].json[\"data\"][\"security_deposit\"]}}, '{{$node[\"Validate Contract\"].json[\"data\"][\"status\"]}}')\nRETURNING id, unit_id, tenant_id, start_date, end_date, monthly_rent, security_deposit, status, created_at;",
"additionalFields": {}
},
"name": "Create Lease",
"type": "n8n-nodes-base.postgres",
"typeVersion": 1,
"position": [
850,
400
],
"credentials": {
"postgres": {
"name": "<your credential>"
}
}
},
{
"parameters": {
"operation": "executeQuery",
"query": "UPDATE units SET status = 'occupied' WHERE id = '{{$node[\"Create Lease\"].json[\"rows\"][0][\"unit_id\"]}}'",
"additionalFields": {}
},
"name": "Update Unit Status",
"type": "n8n-nodes-base.postgres",
"typeVersion": 1,
"position": [
1050,
400
],
"credentials": {
"postgres": {
"name": "<your credential>"
}
}
},
{
"parameters": {
"operation": "executeQuery",
"query": "SELECT t.first_name, t.last_name, t.email, t.phone, t.whatsapp, t.preferred_contact_method,\n u.unit_number, p.name as property_name, p.address\nFROM tenants t\nJOIN units u ON u.id = '{{$node[\"Create Lease\"].json[\"rows\"][0][\"unit_id\"]}}'\nJOIN properties p ON u.property_id = p.id\nWHERE t.id = '{{$node[\"Create Lease\"].json[\"rows\"][0][\"tenant_id\"]}}'",
"additionalFields": {}
},
"name": "Get Tenant and Property Details",
"type": "n8n-nodes-base.postgres",
"typeVersion": 1,
"position": [
1250,
400
],
"credentials": {
"postgres": {
"name": "<your credential>"
}
}
},
{
"parameters": {
"functionCode": "// Prepare welcome message and contract details\nconst lease = $node[\"Create Lease\"].json.rows[0];\nconst tenant = $input.item.json.rows[0];\n\n// Format dates\nconst startDate = new Date(lease.start_date).toLocaleDateString();\nconst endDate = new Date(lease.end_date).toLocaleDateString();\n\n// Format amounts with currency\nconst formattedRent = new Intl.NumberFormat('pt-BR', { style: 'currency', currency: 'BRL' }).format(lease.monthly_rent);\nconst formattedDeposit = new Intl.NumberFormat('pt-BR', { style: 'currency', currency: 'BRL' }).format(lease.security_deposit);\n\n// Create welcome message\nconst welcomeMessage = `*Bem-vindo ao ${tenant.property_name}!*\\n\\nOl\u00e1 ${tenant.first_name},\\n\\nEstamos felizes em t\u00ea-lo como nosso novo inquilino! Seu contrato de aluguel foi registrado com sucesso.\\n\\n*Detalhes do Contrato:*\\nPropriedade: ${tenant.property_name}\\nUnidade: ${tenant.unit_number}\\nEndere\u00e7o: ${tenant.address}\\nData de In\u00edcio: ${startDate}\\nData de T\u00e9rmino: ${endDate}\\nAluguel Mensal: ${formattedRent}\\nDep\u00f3sito de Seguran\u00e7a: ${formattedDeposit}\\n\\nPara qualquer d\u00favida ou assist\u00eancia, voc\u00ea pode entrar em contato conosco atrav\u00e9s deste n\u00famero de WhatsApp.\\n\\nAtenciosamente,\\nEquipe de Administra\u00e7\u00e3o`;\n\n// Create notification for property manager\nconst managerMessage = `Novo Contrato Registrado\\n\\nPropriedade: ${tenant.property_name}\\nUnidade: ${tenant.unit_number}\\nInquilino: ${tenant.first_name} ${tenant.last_name}\\nContato: ${tenant.phone}\\n\\nData de In\u00edcio: ${startDate}\\nData de T\u00e9rmino: ${endDate}\\nAluguel Mensal: ${formattedRent}\\nDep\u00f3sito de Seguran\u00e7a: ${formattedDeposit}\\n\\nID do Contrato: ${lease.id}`;\n\nreturn {\n welcomeMessage,\n managerMessage,\n tenant,\n lease\n};"
},
"name": "Prepare Welcome Message",
"type": "n8n-nodes-base.function",
"typeVersion": 1,
"position": [
1450,
400
]
},
{
"parameters": {
"operation": "executeQuery",
"query": "INSERT INTO messages (tenant_id, direction, channel, content, status)\nVALUES ('{{$node[\"Create Lease\"].json[\"rows\"][0][\"tenant_id\"]}}', 'outgoing', '{{$node[\"Prepare Welcome Message\"].json[\"tenant\"][\"preferred_contact_method\"]}}', '{{$node[\"Prepare Welcome Message\"].json[\"welcomeMessage\"]}}', 'pending')\nRETURNING id;",
"additionalFields": {}
},
"name": "Create Welcome Message",
"type": "n8n-nodes-base.postgres",
"typeVersion": 1,
"position": [
1650,
300
],
"credentials": {
"postgres": {
"name": "<your credential>"
}
}
},
{
"parameters": {
"operation": "executeQuery",
"query": "SELECT phone FROM emergency_contacts\nWHERE role = 'property_manager'\nAND property_id = (SELECT property_id FROM units WHERE id = '{{$node[\"Create Lease\"].json[\"rows\"][0][\"unit_id\"]}}')\nORDER BY priority ASC\nLIMIT 1;",
"additionalFields": {}
},
"name": "Get Property Manager",
"type": "n8n-nodes-base.postgres",
"typeVersion": 1,
"position": [
1650,
500
],
"credentials": {
"postgres": {
"name": "<your credential>"
}
}
},
{
"parameters": {
"method": "POST",
"url": "https://graph.facebook.com/v17.0/{{$env.WHATSAPP_PHONE_NUMBER_ID}}/messages",
"authentication": "genericCredentialType",
"genericAuthType": "httpHeaderAuth",
"sendBody": true,
"bodyParameters": {
"parameters": [
{
"name": "messaging_product",
"value": "whatsapp"
},
{
"name": "recipient_type",
"value": "individual"
},
{
"name": "to",
"value": "={{$node[\"Prepare Welcome Message\"].json[\"tenant\"][\"whatsapp\"]}}"
},
{
"name": "type",
"value": "text"
},
{
"name": "text",
"parameters": [
{
"name": "body",
"value": "={{$node[\"Prepare Welcome Message\"].json[\"welcomeMessage\"]}}"
}
]
}
]
},
"options": {}
},
"name": "Send Welcome Message",
"type": "n8n-nodes-base.httpRequest",
"typeVersion": 3,
"position": [
1850,
300
],
"credentials": {
"httpHeaderAuth": {
"name": "<your credential>"
}
}
},
{
"parameters": {
"method": "POST",
"url": "https://graph.facebook.com/v17.0/{{$env.WHATSAPP_PHONE_NUMBER_ID}}/messages",
"authentication": "genericCredentialType",
"genericAuthType": "httpHeaderAuth",
"sendBody": true,
"bodyParameters": {
"parameters": [
{
"name": "messaging_product",
"value": "whatsapp"
},
{
"name": "recipient_type",
"value": "individual"
},
{
"name": "to",
"value": "={{$node[\"Get Property Manager\"].json[\"rows\"][0][\"phone\"]}}"
},
{
"name": "type",
"value": "text"
},
{
"name": "text",
"parameters": [
{
"name": "body",
"value": "={{$node[\"Prepare Welcome Message\"].json[\"managerMessage\"]}}"
}
]
}
]
},
"options": {}
},
"name": "Notify Property Manager",
"type": "n8n-nodes-base.httpRequest",
"typeVersion": 3,
"position": [
1850,
500
],
"credentials": {
"httpHeaderAuth": {
"name": "<your credential>"
}
}
},
{
"parameters": {
"respondWith": "json",
"responseCode": 201,
"responseData": "={\n \"success\": true,\n \"message\": \"Lease created successfully\",\n \"data\": $node[\"Create Lease\"].json.rows[0]\n}",
"options": {}
},
"name": "Success Response",
"type": "n8n-nodes-base.respondToWebhook",
"typeVersion": 1,
"position": [
2050,
400
]
}
],
"connections": {
"Create Contract Webhook": {
"main": [
[
{
"node": "Validate Contract",
"type": "main",
"index": 0
}
]
]
},
"Validate Contract": {
"main": [
[
{
"node": "Validation Check",
"type": "main",
"index": 0
}
]
]
},
"Validation Check": {
"main": [
[
{
"node": "Error Response",
"type": "main",
"index": 0
}
],
[
{
"node": "Create Lease",
"type": "main",
"index": 0
}
]
]
},
"Create Lease": {
"main": [
[
{
"node": "Update Unit Status",
"type": "main",
"index": 0
}
]
]
},
"Update Unit Status": {
"main": [
[
{
"node": "Get Tenant and Property Details",
"type": "main",
"index": 0
}
]
]
},
"Get Tenant and Property Details": {
"main": [
[
{
"node": "Prepare Welcome Message",
"type": "main",
"index": 0
}
]
]
},
"Prepare Welcome Message": {
"main": [
[
{
"node": "Create Welcome Message",
"type": "main",
"index": 0
},
{
"node": "Get Property Manager",
"type": "main",
"index": 0
}
]
]
},
"Create Welcome Message": {
"main": [
[
{
"node": "Send Welcome Message",
"type": "main",
"index": 0
}
]
]
},
"Get Property Manager": {
"main": [
[
{
"node": "Notify Property Manager",
"type": "main",
"index": 0
}
]
]
},
"Send Welcome Message": {
"main": [
[
{
"node": "Success Response",
"type": "main",
"index": 0
}
]
]
},
"Notify Property Manager": {
"main": [
[
{
"node": "Success Response",
"type": "main",
"index": 0
}
]
]
}
}
}
Credentials you'll need
Each integration node will prompt for credentials when you import. We strip credential IDs before publishing — you'll add your own.
httpHeaderAuthpostgres
Pro
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About this workflow
Contracts Module. Uses postgres, httpRequest. Webhook trigger; 13 nodes.
Source: https://github.com/i486pc/VaulltOptAppWeb/blob/02190e44db933a703c5a4e6eb972bcdc490a5bc2/n8n-workflows/contracts-module.json — original creator credit. Request a take-down →
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