replit-cost-tuning

# Replit Cost Tuning

## Overview
Optimize Replit spending across deployment compute, seat licenses, egress, and storage. Covers right-sizing deployment resources, choosing between Autoscale and Reserved VM, eliminating idle Repls, and managing team seat costs.

## Prerequisites
- Replit account with billing access
- Understanding of current deployment architecture
- Access to usage metrics in Replit dashboard

## Replit Pricing Model

| Component | Pricing |
|-----------|---------|
| **Replit Core** | $25/month (includes $8 flexible credits) |
| **Replit Pro** | $40/month (team features + credits) |
| **Autoscale** | Pay per compute unit consumed |
| **Reserved VM** | From $0.20/day (~$6.20/month) |
| **Static Deploy** | Free (CDN-backed) |
| **Egress** | $0.10/GiB over monthly allowance |
| **PostgreSQL** | Included in plan allowance |
| **Object Storage** | Included in plan allowance |

## Instructions

### Step 1: Audit Deployment Costs
Review what you're spending and where:

```markdown
In Replit Dashboard > Billing:
1. View "Usage" tab for compute breakdown
2. Sort by cost to find expensive Repls
3. Check "Always On" Repls (legacy) — convert to Deployments

Key metrics to check:
- CPU hours consumed per Repl
- Memory-hours consumed per Repl
- Egress data transfer per Repl
- Number of cold starts (Autoscale)
```

### Step 2: Right-Size Deployment Resources
```yaml
# Match resources to actual workload

micro:  # Simple bot, webhook receiver
  type: autoscale
  cost: "Pay per request (free when idle)"
  best_for: "< 1000 requests/day, tolerates cold starts"

small:  # Basic API or web app
  type: reserved_vm
  cpu: 0.25 vCPU
  memory: 512 MB
  cost: "~$6/month"
  best_for: "Low traffic, always-on required"

medium:  # Production web app
  type: reserved_vm
  cpu: 0.5 vCPU
  memory: 1 GB
  cost: "~$12/month"
  best_for: "Standard traffic, good response times"

large:  # Compute-heavy or high-traffic
  type: reserved_vm
  cpu: 2 vCPU
  memory: 4 GB
  cost: "~$40/month"
  best_for: "High traffic, background processing"

# Rule of thumb: if peak CPU < 30% and peak memory < 50%, downsize
```

### Step 3: Choose Autoscale vs Reserved VM
```markdown
Use AUTOSCALE when:
- Traffic is unpredictable or bursty
- App can tolerate 5-15s cold starts
- Many hours of zero traffic per day
- Low daily request count (< 5000)
- Cost: $0 when idle, proportional to traffic

Use RESERVED VM when:
- Traffic is consistent throughout the day
- App needs instant response times
- Running cron jobs, webhooks, or WebSocket
- Cost: fixed monthly, predictable
- Cheaper than Autoscale when utilization > 60%

Use STATIC when:
- Frontend-only app (HTML/CSS/JS)
- No server-side processing needed
- Cost: FREE (CDN-backed, auto-cached)
```

### Step 4: Reduce Egress Costs
Egress (outbound data) costs $0.10/GiB over your plan allowance:

```typescript
// Compress API responses
import compression from 'compression';
app.use(compression());  // gzip responses — reduces egress 60-80%

// Paginate large responses
app.get('/api/items', async (req, res) => {
  const limit = Math.min(parseInt(req.query.limit as string) || 50, 100);
  const { rows } = await pool.query('SELECT * FROM items LIMIT $1', [limit]);
  res.json(rows);
});

// Serve static assets from CDN, not Replit
// Use Cloudflare, Vercel, or other CDN for images/videos/large files
// Only serve API responses from Replit deployment
```

### Step 5: Team Seat Optimization
```markdown
Seat audit checklist:
1. Export member list: Team Settings > Members
2. Identify inactive members (no activity in 30+ days)
3. Remove or downgrade inactive members
4. Consider "Viewer" role for stakeholders who only need read access

Cost calculation:
- 15 seats at $25/month = $375/month
- Remove 4 inactive = $100/month savings = $1,200/year

Quarterly seat review:
- [ ] Export activity report
- [ ] Remove members with 0 activity in 30 days
- [ ] Downgrade read-only members to viewer
- [ ] Document seat allocation decisions
```

### Step 6: Eliminate Idle Repls
```markdown
In Replit Dashboard:
1. View all Repls by last edited date
2. Archive Repls not edited in 90+ days
3. Delete old test/experiment Repls
4. Convert "Always On" Repls to Deployments
   (Always On is legacy and more expensive)

Deployments to review:
- Is this deployed and unused? → Undeploy
- Is this Autoscale with zero traffic? → No cost (good)
- Is this Reserved VM with zero traffic? → Undeploy or switch to Autoscale
```

### Step 7: Optimize PostgreSQL Usage
```markdown
PostgreSQL costs:
- Included in plan credits
- Separate dev and prod databases (charged separately)
- Storage grows with data

Optimization:
- Delete old development databases
- Vacuum and clean up unused tables
- Archive old data to Object Storage
- Use KV Database for simple key-value (included, no extra cost)
```

## Cost Monitoring Dashboard
```typescript
// Track resource usage in your app
app.get('/admin/costs', requireAuth, (req, res) => {
  const mem = process.memoryUsage();
  res.json({
    deployment: {
      type: process.env.REPLIT_DEPLOYMENT_TYPE || 'unknown',
      uptime: process.uptime(),
      memoryMB: Math.round(mem.rss / 1024 / 1024),
    },
    database: {
      poolSize: pool.totalCount,
      activeConnections: pool.idleCount,
    },
    repl: {
      slug: process.env.REPL_SLUG,
      owner: process.env.REPL_OWNER,
    },
  });
});
```

## Error Handling
| Issue | Cause | Solution |
|-------|-------|----------|
| Unexpected high bill | Reserved VM running unused | Undeploy or switch to Autoscale |
| Egress overage | Serving large files from Repl | Move to CDN |
| Seat costs growing | No quarterly audit | Schedule regular seat reviews |
| Cold start complaints | Using Autoscale | Switch to Reserved VM for latency-sensitive apps |

## Resources
- [Replit Pricing](https://replit.com/pricing)
- [Usage-Based Billing](https://docs.replit.com/billing/about-usage-based-billing)
- [Deployment Types](https://docs.replit.com/hosting/deployments)

## Next Steps
For architecture planning, see `replit-reference-architecture`.