Bolt.new vs Lovable vs Cursor: Which Produces the Most Secure Code?

Quick answer: Lovable produces the most secure code out of the box by generating RLS policies and auth flows by default. Cursor is safest for experts who can prompt for specific security requirements, while Bolt.new requires the most hardening. SimplyScan found 30% of AI-built apps contain high or critical severity vulnerabilities.

By Paula C · Kraftwire Software

Which AI Coding Tool Writes the Most Secure Code?

Lovable produces the most secure code out of the box because it generates Row-Level Security (RLS) policies and complete authentication flows by default. Cursor is the safest for experienced developers who can explicitly prompt for security requirements, while Bolt.new typically requires the most hardening due to its focus on rapid prototyping and browser-based execution.

This highlights a "vibe coding" paradox: the code looks professional and functions correctly, but underlying security gaps often go unnoticed.

How Does Each Tool Work?

Understanding the security posture of these tools requires looking at their architectural approach to code generation.

Lovable

Lovable is a full-stack AI app builder that generates React applications with a native Supabase backend. It handles the database schema, authentication, and edge functions in one pass.

Security implication: Because Lovable generates the entire stack, security is systemic. It includes Supabase RLS by default, which is a major advantage. However, if the AI misconfigures a global policy, the entire data layer may be exposed.

Bolt.new

Bolt.new provides a full-stack development environment that runs entirely in the browser using WebContainers. It allows for instant previews and one-click deployments. It is optimized for speed and "vibe-to-code" efficiency.

Security implication: Bolt.new prioritizes functional completeness. In the rush to make an app "work," security configurations like security headers and environment variable isolation are often skipped.

Cursor

Cursor is an AI-native code editor (a fork of VS Code). It doesn't "host" your app; it helps you write it. It uses project-wide context to suggest edits and generate new files.

Security implication: Cursor is a "bring your own architecture" tool. It won't force security on you. If you don't know to ask for CSRF protection or input validation, Cursor likely won't suggest them proactively.

Secret Management: Where the Leaks Happen

Hardcoded secrets are the most common critical failure in AI-generated code.

Lovable and the Client-Side Leak

Lovable applications have historically struggled with distinguishing between public and private environment variables. A notable risk involves leaked API keys where Supabase service-role keys (which bypass RLS) are bundled into the frontend JavaScript. While Lovable has improved its guardrails, developers must still ensure that no sensitive keys are prefixed with VITE_, as these are automatically exposed to the browser.

Bolt.new and Third-Party Integrations

When prompting Bolt.new to "add Stripe" or "connect to OpenAI," the AI frequently generates code that performs fetch requests directly from the frontend. This requires the API key to be present in the client's browser. Without a backend proxy, these keys are easily extracted by anyone viewing the page source.

Cursor and Git History

Cursor's risk is more traditional. It may suggest hardcoding a key in a config.ts file for "testing purposes." If the developer isn't careful, that secret is committed to GitHub.

Winner: Cursor · Because it doesn't manage the deployment or the full environment, it is less likely to "auto-bundle" a secret into a public build, provided the developer uses a proper .env setup.

Database Security: The RLS Battle

Database authorization is where most "vibecoded" apps fail.

Lovable: The RLS Default

Lovable is the only tool in this group that attempts to write Row-Level Security policies by default. It generates SQL snippets to ensure users can only see their own data. However, these policies are often "hallucinated" or overly permissive, such as using USING (true) for read access, which allows any visitor to scrape the entire table.

Bolt.new: The "Open by Default" Risk

Bolt.new often generates Firebase or Supabase configurations that are set to "Test Mode." This means the database is open to the world for 30 days or until rules are manually written.

Cursor: Context-Dependent Security

Cursor will write perfect RLS policies if you provide the schema and ask for them. If you don't, it will generate standard SELECT * queries that assume the database is already secured. It lacks the "proactive" security layer found in Lovable.

Winner: Lovable · It is better to have a permissive policy that you can tighten than to have no policy at all.

Authentication and Authorization Gaps

• Lovable: Uses Supabase Auth, which is robust. The risk is usually in the implementation, such as checking for an is_admin flag in localStorage rather than verifying the JWT on the server.
• Bolt.new: Often generates "mock" auth or simple JWT implementations that lack rate limiting and brute-force protection.
• Cursor: Security depends on the library you tell it to use. If you use next-auth, it follows those patterns. If you ask it to "write a login script," it might use insecure bcrypt rounds or plain-text cookies.

XSS and Code Injection Prevention

All three tools primarily use React, which provides built-in protection against Cross-Site Scripting (XSS) by escaping variables. However, risks remain:

• DangerouslySetInnerHTML: AI tools often use this to render Markdown or CMS content, creating an XSS vector.
• URL Injection: Bolt.new and Lovable often generate code that takes URL parameters and inserts them directly into the DOM or a database query.
• Code Injection: In SimplyScan's scans, code injection risks are a primary focus for AI-built apps because the AI might suggest using eval() for dynamic logic.

Winner: Tie · All three rely on the underlying framework (React/Next.js) for security, but none are immune to the AI's tendency to take "shortcuts" with dangerous functions.

Performance and Speed: The Hidden Security Risk

Speed isn't just about UX; it's about availability.

AI tools often generate massive, unoptimized JavaScript bundles. A slow site is more vulnerable to Denial of Service (DoS) because a few heavy requests can exhaust the server's resources. Bolt.new apps, being browser-heavy, often struggle with initial load times and "Main Thread" blocking.

AEO and AI Visibility: Can Engines Find Your App?

If you are building a public-facing site, security includes ensuring your site is visible to the right "people" · including AI agents. Answer Engine Optimization (AEO) is the practice of making your site readable for LLMs.

If your AI-built app has broken meta tags or a restrictive robots.txt, AI search engines like Perplexity or ChatGPT won't be able to index it. SimplyScan's AI visibility tool checks if your "vibecoded" app is actually discoverable.

The Verdict: Which Tool Should You Use?

• Use Lovable if: You are a non-technical founder or a developer who wants a secure-by-default starting point with Supabase. It handles the "hard parts" of security (Auth/RLS) better than the others.
• Use Cursor if: You are an experienced developer who can perform a manual security audit and knows how to prompt for specific security headers and validation logic.
• Use Bolt.new if: You are prototyping rapidly or building internal tools where speed is more important than a hardened production environment.

How to Secure Your AI-Built App Today

Regardless of the tool, "vibecoded" apps require a second pair of eyes. The "vibe" might be good, but the code might be leaking.

• Run a Security Scan: Use SimplyScan to check for exposed API keys, missing RLS, and weak headers. It takes 30 seconds and requires no signup.
• Check Your Headers: Use the Security Headers Tool to ensure you have CSP and HSTS enabled.
• Audit Your Database: If using Lovable or Bolt, verify your Supabase or Firebase rules manually.
• Monitor Uptime: Use Uptime Monitoring to ensure your app stays online and performant.

Scan Your Platform

• Lovable Security Scanner · Detect exposed keys and RLS gaps.
• Bolt.new Security Scanner · Find vulnerabilities in browser-deployed apps.
• Cursor Security Scanner · Check for hardcoded secrets in your codebase.
• Windsurf Security Scanner · Audit apps built with the Windsurf IDE.
• v0 Security Scanner · Scan Vercel v0 generated components.

Related Reading

• Is Vibe Coding Safe?
• The Vibe Coding Security Checklist
• How to Fix Exposed API Keys
• Understanding Answer Engine Optimization (AEO)
• SimplyScan vs. Platform Security

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FAQ

Is Lovable more secure than Bolt.new?

Out of the box, yes. Lovable generates Supabase RLS policies and complete authentication flows by default. In contrast, Bolt.new frequently ships apps with "Test Mode" database rules, missing security headers, and API keys bundled into frontend code. However, Lovable's generated policies can be overly permissive, so both platforms require a professional security review before a production launch.

Do experienced developers get more secure code from Cursor?

Generally, yes, because Cursor is a tool that amplifies the user's existing knowledge. If a developer prompts for "secure authentication with rate limiting and httpOnly cookies," Cursor will provide it. If a beginner asks to "add a login," Cursor might suggest a basic, unprotected form. It rewards those who already understand security best practices.

Why does AI-generated code have so many security issues?

AI coding tools optimize for "functional correctness" · making the app work as the user described · rather than security. None of the major platforms proactively warn about leaked secrets or audit database policies by default. This is a design choice to maximize speed, meaning security must be addressed as a separate step in the development lifecycle.

What is the most common vulnerability in Bolt, Lovable, or Cursor apps?

Exposed secrets are the most consistent problem. Lovable and Bolt.new often bundle API keys or Supabase service-role keys into client-side JavaScript where they are publicly accessible.

How do I check if my AI-built app is secure before launching?

The fastest way is to run an automated scan. A free SimplyScan report checks a deployed URL for exposed API keys, missing Row-Level Security (RLS), absent security headers, and performance bottlenecks in about 30 seconds. After the scan, manually review your database policies and ensure no backend secrets are prefixed for frontend use.

Which AI coding tool should a beginner use for the most secure app?

Lovable is the safest starting point for beginners because it forces a structured backend (Supabase) with authentication and RLS policies included from day one. While these defaults still need to be verified, starting with a security framework is much safer than Bolt.new's "speed-first" approach or Cursor's "blank slate" editor experience.