Deno Deploy: AI-Optimized Technical Reference

Configuration

Runtime Architecture

• V8 Isolates: <50ms startup vs Lambda's 300-800ms containers
• TypeScript Native: No build steps, direct SWC transpilation
• Edge Distribution: 6 regions (vs Cloudflare's 300+)
• Memory Limit: 512MB hard limit - exceeding causes immediate termination
• Execution Time: 50ms limit per request (vs Lambda's 15 minutes)

Working Production Settings

// Direct TypeScript imports work
import { serve } from "https://deno.land/std@0.200.0/http/server.ts"

// Environment variables
const config = Deno.env.get("NODE_ENV")

// File operations (FORBIDDEN - will crash)
// fs.readFile() → Error: Forbidden API access
// Use KV storage instead

Security Model

• All APIs locked by default
• No filesystem access
• No private network access
• Automatic HTTPS with Let's Encrypt

Resource Requirements

Migration Time Costs

• Simple APIs: 1-2 days per Node.js app
• Complex Apps: 2-4 days each (triple initial estimates)
• Success Rate: 25% work immediately, 50% need significant refactoring, 25% require complete rewrite
• Breaking Changes: Every Node.js filesystem operation, CommonJS imports, process globals

Expertise Requirements

• TypeScript Proficiency: Essential
• Deno API Knowledge: Required for migration
• Edge Computing Understanding: Helpful for optimization
• Migration Planning: Critical - budget 3x estimated time

Cost Structure

• Free Tier: 1M requests/month, 100GB bandwidth
• Pro Plan: $20/month for 5M requests, then $2/million
• Breaking Point: 3-4M monthly requests (upgrade to Pro)
• Hidden Costs: $0.50/GB bandwidth overage, $2.50/million KV writes

Critical Warnings

Production Failure Modes

Memory Exhaustion

• Symptom: Memory limit exceeded, isolate terminated
• Trigger: 512MB limit hit (no gradual degradation)
• Recovery Time: 5 minutes for new isolate provisioning
• Solution: Implement streaming for large data processing

Node.js Migration Failures

// These WILL break your deployment:
process.env.NODE_ENV           // ReferenceError: process is not defined
fs.readFile()                  // Error: Forbidden API access
require('./config')            // Error: Cannot resolve module
Buffer.from()                  // ReferenceError: Buffer is not defined
__dirname                      // ReferenceError: __dirname is not defined

Bandwidth Cost Disasters

• Viral Content: 300GB spike = $150 surprise bill
• Image Serving: Use CDN, not Deploy bandwidth
• Video Streaming: Completely unsuitable - will bankrupt you

KV Storage Gotchas

• Debug Logging: 2M writes = $5/day in charges
• Analytics Storage: Can reach $300/month in write costs
• Monitoring Required: Watch KV operations closely

Regional Coverage Limitations

• Limited Edge: Only 6 regions vs competitors' 300+
• SEA/Africa Impact: 180ms+ latency for underserved regions
• Alternative: Cloudflare Workers for global coverage

Platform Limitations

• WebSocket Support: Available (rare for serverless)
• Long Processing: Impossible (50ms limit)
• File Operations: Completely forbidden
• Native Modules: Cannot be used

Decision Criteria

Choose Deno Deploy When:

• TypeScript-first development required
• <50ms cold starts critical
• WebSocket support needed
• Simple API architecture
• 1-10M monthly requests
• Team comfortable with Deno ecosystem

Avoid Deno Deploy When:

• Global edge coverage critical (use Cloudflare)
• Heavy file processing required (use traditional servers)
• Long-running tasks needed (use Lambda)
• Existing large Node.js codebase (migration costs too high)
• Budget-sensitive with potential viral traffic

Cost-Benefit Analysis

• Break-even: More cost-effective than Vercel at 3M+ requests
• Bandwidth Risk: High for content-heavy applications
• Development Speed: Faster than webpack-based platforms
• Migration Investment: High for existing Node.js applications

Comparative Analysis

Factor	Deno Deploy	Cloudflare Workers	AWS Lambda	Vercel Edge
Cold Start	<50ms	<10ms	300-1000ms	<50ms
Global Coverage	6 regions	300+ locations	24 regions	10+ regions
TypeScript	Native	Build required	Build required	Sometimes native
Memory Limit	512MB	128MB	128MB-10GB	128MB
WebSockets	Yes	Yes	No	No
Free Tier	1M req/month	100K req/day	1M req/month	100K req/month

Implementation Reality

Successful Use Cases

• JSON APIs with minimal bandwidth
• Real-time chat applications (WebSocket advantage)
• Server-side rendered pages with external assets
• TypeScript-native development workflows

Failure Scenarios

• File upload/processing services
• Image hosting without CDN
• CPU-intensive background jobs
• Legacy Node.js applications with filesystem dependencies

Support Quality

• Discord community: Active for troubleshooting
• Documentation: Basic, Stack Overflow fills gaps
• Enterprise: Dedicated support with <30min response
• Status Communication: Transparent during outages

Operational Intelligence

Production Readiness Assessment

• Uptime: 99.9%+ observed (18-month production use)
• Incident Response: Good communication, quick resolution
• Scale Handling: Processes 255M daily requests for Netlify
• Backup Strategy: 30-minute migration to Cloudflare Workers recommended

Hidden Costs Beyond Pricing

• Developer Time: 3x estimated migration effort
• Monitoring Tools: External logging required (KV writes expensive)
• CDN Setup: Essential for bandwidth cost control
• Team Training: Deno ecosystem learning curve

Community Wisdom

• Keep external backup deployment ready
• Monitor bandwidth usage obsessively
• Use KV sparingly for writes
• Plan migration time conservatively
• Test memory limits early in development