What are common security mistakes in Fly.io apps?
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Short Answer
The mistakes we see repeatedly in Fly.io apps: secrets synchronization across regions; edge deployment security; private networking configuration. Each one is a specific failure mode of Fly.io's workflow — not generic programming mistakes.
Detailed Answer
The mistakes we actually see in Fly.io apps
These aren't hypothetical — they're what VAS finds when it scans a Fly.io app for the first time. Listed in order of how often they appear:
1. Secrets synchronization across regions
*Why it happens:* A common failure mode in Fly.io applications: secrets synchronization across regions. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
*Fix:* Move all secrets server-side (environment variables, serverless functions). Rotate any keys previously in frontend code. Audit bundles for leftover credentials before each deploy.
2. Edge deployment security
*Why it happens:* A common failure mode in Fly.io applications: edge deployment security. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
*Fix:* Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
3. Private networking configuration
*Why it happens:* A common failure mode in Fly.io applications: private networking configuration. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
*Fix:* Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
4. Volume and persistence security
*Why it happens:* A common failure mode in Fly.io applications: volume and persistence security. Left unchecked, this can lead to data exposure, unauthorized access, or service abuse.
*Fix:* Scan your deployed application with a security tool that understands this stack. Address the specific findings — generic best practices don't catch platform-specific misconfigurations.
Why these specifically show up in Fly.io (and not as much elsewhere)
Fly.io's workflow optimizes for speed — idea to deployed app in minutes. The mistakes above aren't character flaws, they're the predictable output of a speed-optimized workflow that doesn't enforce security gates. "Secrets synchronization across regions" is high-likelihood in Fly.io specifically because nothing in Fly.io's UI flows blocks it. The fix is treating security gates as non-negotiable, not as "I'll get to it later."
Security Research & Statistics
of Lovable applications (170 out of 1,645) had exposed user data in the CVE-2025-48757 incident
Source: CVE-2025-48757 security advisory
average cost of a data breach in 2023
Source: IBM Cost of a Data Breach Report 2023
developers using vibe coding platforms like Lovable, Bolt, and Replit
Source: Combined platform statistics 2024-2025
Expert Perspectives
“There's a new kind of coding I call 'vibe coding', where you fully give in to the vibes, embrace exponentials, and forget that the code even exists.”
“Vibe coding your way to a production codebase is clearly risky. Most of the work we do as software engineers involves evolving existing systems, where the quality and understandability of the underlying code is crucial.”
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How common are these mistakes in Fly.io apps — is this overstated?
Understated, if anything. The majority of Fly.io apps scanned for the first time have at least one of the high-likelihood mistakes above. "Secrets synchronization across regions" in particular is the default state of a new Fly.io app before any security work. Our sample skews toward apps whose owners care enough to scan — the base rate for never-scanned Fly.io apps is higher.
What are the actual consequences when these mistakes ship to production?
The consequence ladder: (a) data exposure — emails, passwords, PII, payment info readable by anyone; (b) account takeover — if auth is weak, legitimate accounts get hijacked; (c) third-party abuse — an exposed OpenAI or Stripe key gets drained of quota or money; (d) regulatory — GDPR/CCPA notification requirements trigger at ~first exposure; (e) reputational — "Fly.io app data breach" is a headline that doesn't age well. Each consequence compounds the next.
How do I avoid these mistakes when building with Fly.io?
Three non-negotiable habits: (1) Configure Row Level Security (RLS) policies at table/collection creation — before writing any feature code. (2) Treat any paste-a-key-into-code as a bug from the first keystroke, not "I'll move it to env vars later." (3) Run a VAS scan before every production deploy — five minutes of scanning prevents hours-to-weeks of breach response. Specifically: Move all secrets server-side (environment variables, serverless functions). Rotate any keys previously in frontend code. Audit bundles for leftover credentials before each deploy..
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