Evolution API Management

Overview

Operational guide for Evolution API v2.3.7 on ECS Fargate with WhatsApp Baileys integration. Covers instance lifecycle, session management, environment isolation, and troubleshooting.

Core constraint: WhatsApp allows only ONE active Baileys connection per phone number. Two instances with the same number = continuous conflict/replaced loop every ~2 seconds.

Quick Reference

All endpoints require header: apikey: $AUTHENTICATION_API_KEY

ECS Exec Commands

Container is BusyBox-based: no curl/wget. Use node -e for everything.

# Template for all ECS exec commands
aws ecs execute-command \
  --cluster "$CLUSTER" \
  --task "$TASK_ID" \
  --container EvolutionService \
  --interactive \
  --command 'node -e "...script..."'

Get task ID:

TASK_ID=$(aws ecs list-tasks --cluster "$CLUSTER" --service-name EvolutionService \
  --query 'taskArns[0]' --output text | awk -F/ '{print $NF}')

ECS exec output gotchas:

• Output always contains Starting session... and Cannot perform start session: EOF noise
• Use grep or tail to extract useful data
• Long outputs get truncated (~3KB). For large data: write to file inside container, read in chunks via base64
• Shell escaping through ECS exec is fragile. For complex payloads: base64-encode the JSON body, decode inside the node script

Instance Lifecycle

Create Instance with Webhook

// Body for POST /instance/create
{
  instanceName: 'alinhou-production',
  integration: 'WHATSAPP-BAILEYS',
  qrcode: true,
  rejectCall: false,
  groupsIgnore: true,
  alwaysOnline: false,
  readMessages: false,
  readStatus: false,
  syncFullHistory: false,
  webhook: {
    url: 'https://lambda-url/api/v1/webhook/evolution',
    byEvents: true,
    base64: false,
    events: ['MESSAGES_UPSERT'],
    headers: { jwt_key: 'YOUR_WEBHOOK_SECRET' }  // MUST have a value
  }
}

Update Webhook on Existing Instance

// POST /webhook/set/{instanceName}
// MUST wrap in "webhook" property
{
  webhook: {
    enabled: true,
    url: 'https://lambda-url/api/v1/webhook/evolution',
    webhookByEvents: true,
    webhookBase64: false,
    events: ['MESSAGES_UPSERT'],
    headers: { jwt_key: 'YOUR_WEBHOOK_SECRET' }
  }
}

QR Code Generation Workflow

1. Call /instance/connect/{name} - returns { code, base64, pairingCode }
2. The code field is the raw QR data string (~240 chars)
3. Generate QR locally: npx qrcode -o /tmp/qr.png "$CODE" or use require('qrcode').toDataURL()
4. Create HTML with embedded base64 image (no CDN dependency)
5. Copy to Windows: /mnt/c/Users/{user}/Downloads/
6. QR expires in ~45 seconds - be fast

Never try to pipe base64 image data through ECS exec - it gets truncated and corrupted.

Environment Isolation

The Problem

WhatsApp Baileys protocol enforces single connection per phone number. Staging + production competing = session conflict loop.

The Solution

In SST infra:

WHATSAPP_MOCK: $app.stage === 'production' ? 'false' : 'true',
EVOLUTION_INSTANCE_NAME: `alinhou-${$app.stage}`,
scaling: $app.stage === 'production' ? { min: 1, max: 1 } : { min: 0, max: 0 },

Outage Checker Mock Guard

When WHATSAPP_MOCK=true, getEvolutionStatus() must return early with a healthy stub. Otherwise, it tries to reach a non-existent Evolution container and triggers false-positive outage alert emails after 30 minutes.

Webhook JWT Configuration

• jwt_key goes inside headers object in the webhook config
• Evolution strips jwt_key, generates HS256 JWT with { app: "evolution", action: "webhook" }
• JWT has 10-minute expiry, sent as Authorization: Bearer <token>
• Lambda verifies using EVOLUTION_WEBHOOK_SECRET env var
• EVOLUTION_WEBHOOK_SECRET is NOT in the Evolution container env - only in Lambda. When creating instances via ECS exec, you must pass the secret value directly (get from npx sst secret list)
• Missing JWT key causes: secretOrPrivateKey must have a value error in Evolution logs

Session Persistence

Dual strategy for maximum resilience:

• Database: PostgreSQL Session table (when DATABASE_SAVE_DATA_INSTANCE=true)
• EFS: Mounted at /evolution/instances/ for local Baileys auth files

Either alone is sufficient. Both together = defense in depth.

Deploy Strategy (Stop-First)

// In infra/evolution.ts transform
deploymentMaximumPercent: 100,
deploymentMinimumHealthyPercent: 0,

Old task stops before new starts. ~3-5 min downtime acceptable:

• Outbound messages queue in SQS
• Inbound messages buffered by WhatsApp servers

Brazilian Phone Normalization

WhatsApp sends 12-digit format: 558188101603 (drops mobile 9th digit) Database stores 13-digit format: 5581988101603 (with the 9)

Webhook normalizes: if 12 digits starting with 55, insert 9 at position 4.

Troubleshooting

Container Details

• Image: evoapicloud/evolution-api:v2.3.7 (don't upgrade without staging test)
• BusyBox-based: no curl, no wget, use node -e
• startPeriod: 180s (container + EFS mount + Prisma + Baileys reconnect)
• Health check: node HTTP GET to localhost:8080
• LOG_LEVEL: 'ERROR,WARN,WEBHOOKS' for clean CloudWatch

Cost

Staging Evolution running 24/7 (0.25 vCPU, 1GB ARM64, sa-east-1): ~$8.51/month. Scaling to 0 with mock mode saves this entirely.