My Hosting Bill Hit Like $2,500 Last Month Because I Thought I Was Smart

Every JS runtime has its own creative way of destroying your budget. Node.js kills you with tooling complexity, Deno locks you into their platform, and Bun crashes randomly in prod. Found this out after burning probably like $3,000 during what should have been a "simple" migration that took maybe 8 weeks instead of 2.

Node.js: Death by a Thousand Tools

Node.js works until you count the tooling nightmare. We're running 23 separate tools just to ship JavaScript: npm, webpack, jest, eslint, prettier, husky, commitlint, semantic-release... I probably forgot a few. Every single one has opinions about configuration, breaks during updates, and loves to shit the bed during important releases.

GitHub Actions bill hit around $340 last month because builds take like 12 fucking minutes. Found out we're downloading maybe 400MB of node_modules garbage containing three versions of lodash and some crypto library nobody remembers installing. The problem isn't disk space - it's watching CI burn money downloading the same garbage 50 times a day.

Shit that blindsided me:

• Docker builds: 8 minutes for Node.js vs 2 minutes for Deno doing the same thing
• Security scanning: Snyk charges $99/month to panic about 800-something vulnerabilities we can't actually fix
• "Works on my machine" syndrome happens constantly - probably costs 2 hours per developer per week

Deno: Vendor Lock-in Disguised as Simplicity

Deno's big pitch is built-in TypeScript, testing, and linting. Actually works - went from 23 tools down to just deno. But here's the fucking catch: you're locked into Deno Deploy for hosting. Want to use anything else? Enjoy containerizing everything yourself.

Deployed our API to Deno Deploy for like $47/month vs Vercel's $89. Looked like a win until traffic hit around 2M requests and CPU overages brought the bill to roughly $340. Their "50ms CPU per request" sounds reasonable until every database query eats into that limit.

Reality check: The 15-25% CI/CD savings in blog posts? Only works if you rewrite your entire deployment process. Took us 6 weeks of full-time dev work.

Bun: Fast at Everything Except Stability

Bun installs packages stupid fast - npm install went from 8 minutes to 90 seconds. Amazing until it crashes in prod with "TypeError: Cannot read properties of undefined" and zero stack trace. Good luck debugging that at 2am.

Deployed to Railway expecting lower costs from Bun's efficiency. Memory usage dropped 30%, response times improved, everything looked great. Then Stripe webhooks started failing because Bun's crypto implementation is apparently broken. Spent probably 16 hours debugging before saying fuck it and going back to Node.js.

Learn from my pain: Bun rocks for development. Don't use it for anything touching payments or user data. Just don't.

Memory and Resource Reality Check

Hosting platforms charge for memory allocation, not usage. This means if you provision 1GB but only use 512MB, you pay for 1GB. Each runtime has different memory patterns - check AWS Lambda memory pricing and Railway resource pricing for real costs:

Node.js memory usage is predictable but bloated. Our typical API uses maybe 380MB baseline.
Deno uses around 280MB for equivalent functionality but spikes during module resolution.
Bun starts at like 180MB but memory leaks are common - I think we've seen it hit 1.2GB after 24 hours.

For AWS Lambda, Node.js wins because cold starts are consistent. Deno's 30ms variance means you can't predict costs. Bun's 56ms variance is even worse, plus Lambda doesn't natively support it yet.

Bundle Size Wars Are Stupid

Everyone obsesses over bundle sizes, but CDN costs are tiny compared to compute costs. Our like 2MB bundle costs around $12/month on Vercel's CDN. Reducing it to 1.4MB saves maybe $3/month but took probably 20 hours of optimization.

Real costs that matter more:

• Failed deployments due to build issues: maybe $500 in debugging time last quarter
• Platform migration when your runtime isn't supported: probably $2,000 in developer time
• Monitoring and error tracking for unstable runtimes: around $180/month for better tooling

Enterprise JavaScript hosting is where "save money" becomes "explain to the board why we spent like $50K on tooling." Helped three companies fuck up runtime decisions at scale. The hidden costs make you wonder why you didn't just become a plumber.

When Your Build System Needs Its Own Team

Big Node.js setups are pure DevOps hell. Current client runs 47 different tools for JavaScript. Yes, I actually counted them during a 3am incident. Webpack, babel, eslint, prettier, jest, cypress, storybook, rollup, semantic-release, husky, lint-staged, commitizen... each one breaks in exciting new ways.

The real financial damage:

• Full-time DevOps engineer just to babysit JavaScript tools: around $120K/year + they quit after maybe 8 months
• Snyk Enterprise: like $899/month to panic about I think 3,247 vulnerabilities we can't fix
• GitHub Actions: probably $1,340/month because builds run like 67 times daily and take forever
• Developer time fixing CI: maybe 2 hours/week per dev = roughly $78K/year of developers saying "it worked on my machine"

Deno in enterprise: Tooling gets simple but vendor lock-in gives CTO nightmares. One client loves Deno Deploy until procurement asked "what if they go out of business?" Answer: "Docker containers but you lose everything that made Deno worth it." Great.

Bun in enterprise: Doesn't happen. Security teams see "experimental" and nope out immediately. One company spent like $40K auditing Bun's security, then decided Node.js was "less risky." $40K to confirm what everyone already knew.

Database Costs That Make Zero Sense

Runtime choice fucks with database costs in ways you won't see until the bill shows up and makes you question reality.

Node.js connection pooling is mature but greedy. Each instance holds maybe 20-50 DB connections. With 10 instances that's like 500 connections to PostgreSQL. RDS charges for connection overhead - around $340/month just for the privilege of connecting to our own database.

Deno handles HTTP great, databases terribly. No real connection pooling yet. Our experiment used fetch() for DB queries via HTTP API. Result: 3x higher database CPU because every query is an HTTP request. PlanetScale bill jumped from like $89 to around $267/month.

Bun has fast DB queries until it crashes. Tested like 1,000 concurrent users on PostgreSQL. Performance was incredible for maybe 10 minutes, then died with "out of memory" despite 2GB RAM. Took probably 18 hours to figure out connection pooling leaks memory.

Monitoring: Where Money Disappears

Production monitoring at scale costs more than most people's salaries. Runtime choice determines which overpriced APM tools you get to choose from.

Node.js works with every monitoring tool (lucky you):

• New Relic: around $347/month for 8 hosts (bargain compared to alternatives)
• Datadog: like $891/month because different teams refuse to standardize
• PagerDuty: roughly $156/month to wake up engineers at 3am
• Custom dashboards: maybe $200/month in dev time building shit that should be built-in

Deno monitoring means building everything yourself. Spent probably $15K on custom instrumentation because APM vendors ignore it. Works now but opportunity cost was painful.

Bun monitoring: console.log and prayer. One client tried Bun in prod. Error tracking? Nope. Stack traces? Nope. Observability? Fuck no. Had to hire a support engineer for like $80K/year to manually watch logs.

Security Theater That Costs Real Money

Enterprise security turns runtime selection into a political clusterfuck that lasts months.

Node.js has probably 10,000 ways to get hacked but amazing tools to find them:

• Like 1,800 known vulnerabilities across deps (probably more we don't know about)
• Around $2,340/month for security theater (Snyk + GitHub Advanced + Veracode)
• SOC2 audit found maybe 23 risks we can't actually fix (third-party deps)
• Compliance costs: roughly $40K/year to make auditors happy

Deno security model is cleaner but untested. Security team: "Smaller attack surface, but what happens when the runtime itself gets pwned?" Fair point. No enterprise security tools exist.

Bun security assessment: like 6 months, consultants cost us probably $60-70K. Result: "Insufficient security track record for financial services." Maybe 8 months later, still "evaluating."

Migration Costs That Destroy Budgets

Enterprise runtime migration isn't about code - it's about retraining teams, updating docs nobody reads, and managing political fallout from the CTO's "strategic decision."

Training costs that blindsided us:

• Like 40 hours per dev for Deno training: roughly $96K for 12-person team (half forgot immediately)
• New CI/CD setup: maybe 2 months of DevOps time = around $40K (still not done)
• Security docs update: probably $25K in technical writing nobody will read
• Rollback planning: like $35K (we'll need it)

Political damage control:

• CTO explaining to board why bills doubled during "cost optimization"
• Security team updating procedures they'll never follow
• Procurement renegotiating contracts with vendors who smell blood
• Support team learning new ways to be confused at 3am

When You'll Actually Break Even (Spoiler: Never)

ROI calculations are fantasy until reality hits:

Node.js to Deno disaster:

• Promised savings: like $50K/year (LOL)
• Actual year-one costs: around $196K in migration hell
• Break-even: maybe 4 years if nothing breaks (everything breaks)

Node.js to Bun experiment:

• Performance savings: roughly 30% server cost reduction = around $36K/year
• Security theater and compliance updates: probably $67K upfront
• Break-even: like 2 years if you're not in finance (you probably are)

Real talk: Stick with Node.js for enterprise unless you love explaining budget overruns to executives. The "savings" never justify the shitstorm at scale.