Bolt
security
Missing Input Sanitization in Bolt App Forms
Your Bolt.new application accepts user input from forms, URL parameters, and API requests without validating or sanitizing it. This leaves your app vulnerable to cross-site scripting (XSS), HTML injection, data corruption, and other attacks that exploit unfiltered input.
When Bolt generates form handling code, it often passes user input directly to the database or renders it on the page without checking for malicious content. A user could submit a script tag in a comment field, an extremely long string that breaks your layout, or special characters that corrupt your data.
The consequences range from cosmetic issues (broken layouts) to critical security breaches (stolen user sessions, defaced pages, or unauthorized data access). This is one of the most common security gaps in AI-generated applications.
Error Messages You Might See
Warning: Each child in a list should have a unique key prop
Content Security Policy violation: inline script blocked
Unhandled Runtime Error: Objects are not valid as a React child
XSS payload detected in input field
Common Causes
- No server-side validation — Form data is accepted and stored without checking type, length, or format on the backend
- Using dangerouslySetInnerHTML — Bolt generated React components that render user content as raw HTML, enabling XSS
- Client-only validation — Validation exists in the form component but not in the API route, so it can be bypassed with a direct API call
- No Content Security Policy — Missing CSP headers allow injected scripts to execute freely
- Rich text editors without sanitization — WYSIWYG editors that save and display raw HTML from users
- URL parameters used directly — Query string values rendered on the page without escaping
How to Fix It
- Add server-side validation with Zod — Define strict schemas: const schema = z.object({ name: z.string().min(1).max(100), email: z.string().email() }); and validate every API input
- Never use dangerouslySetInnerHTML with user data — Replace it with regular JSX text rendering: {userComment} instead of dangerouslySetInnerHTML={{__html: userComment}}
- Install DOMPurify for HTML content — If you must render HTML, sanitize it: DOMPurify.sanitize(htmlContent, { ALLOWED_TAGS: ['p', 'b', 'i', 'a'] })
- Add Content-Security-Policy headers — Configure CSP to block inline scripts: Content-Security-Policy: default-src 'self'; script-src 'self'
- Validate on both client and server — Share Zod schemas between frontend forms and backend API routes for consistent validation
Real developers can help you.
Tejas Chokhawala
Full-stack engineer with 5 years experience building production web apps using React, Next.js and TypeScript.
Focused on performance, clean architecture and shipping fast.
Experienced with Supabase/Postgres backends, Stripe billing, and building AI-assisted developer tools.
Jacek Rozanski
Senior PHP/Symfony developer and DevOps engineer with 20+ years of professional experience, running opcode.pl (web development agency, est. 2004).
Day job: I'm the sole backend developer at merketing company where I own and maintain 11 PHP/Symfony microservices on AWS (ECS Fargate, RDS, S3, CloudFront), handle the full CI/CD pipeline (Bitbucket Pipelines, Docker), and manage monitoring with Sentry and CloudWatch. These services handle high request volumes in production every month.
What I bring to AI-built apps:
- I audit and fix security issues (OWASP methodology), performance bottlenecks, and architectural problems in codebases generated by Cursor, Claude Code, Lovable, Bolt, and v0
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- I set up the infrastructure AI tools don't touch: AWS hosting, CI/CD pipelines, automated deployments, database optimization, monitoring, and alerting
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Tech stack: PHP 8.x, Symfony, React, Next.js, PostgreSQL, MySQL, Docker, AWS (ECS, RDS, S3, SQS/SNS, CloudFront), Terraform, Supabase. I also use AI tools daily (Claude Code, Cursor) in my own workflow, so I understand both the strengths and the gaps in AI-generated code.
Based in Poland (CET timezone). Available for async work and calls during EU/US business hours.
Matthew Butler
Systems Development Engineer @ Amazon Web Services
Basel Issmail
’m a Senior Full-Stack Developer and Tech Lead with experience designing and building scalable web platforms. I work across the full development lifecycle, from translating business requirements into technical architecture to delivering reliable production systems.
My work focuses on modern web technologies, including TypeScript, Angular, Node.js, and cloud-based architectures. I enjoy solving complex technical problems and helping teams turn product ideas and prototypes into working platforms that can grow and scale.
In addition to development, I often collaborate closely with product managers, business analysts, designers, and QA teams to ensure that solutions align with both technical and business goals.
I enjoy working with startups and product teams where I can contribute both as a hands-on engineer and as a technical partner in designing and delivering impactful software.
David Olverson
Solo dev shipping production apps with AI-assisted development. I specialize in rescuing broken Lovable/Bolt/Cursor builds and taking them to production. 10+ apps shipped including SaaS CRMs, gaming platforms, real estate tools, and Discord bots. Stack: Next.js 16, TypeScript, Tailwind CSS, FastAPI, PostgreSQL, Prisma. I use Claude Code with 50+ custom skills for rapid delivery. Average turnaround: 2-4 weeks from broken prototype to production.
BurnHavoc
Been around fixing other peoples code for 20 years.
Stanislav Prigodich
15+ years building iOS and web apps at startups and enterprise companies. I want to use that experience to help builders ship real products - when something breaks, I'm here to fix it.
Vlad Temian
15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox).
Cursor ambassador and agentic tooling builder.
I've scaled systems, automated deployments, and built observability tools for AI coding workflows. I specialize in taking vibe-coded apps from broken prototype to production-ready: fixing Supabase auth/RLS, Stripe integrations, deployment pipelines, and cleaning up AI-generated spaghetti.
I build tools in this space (agentprobe, claudebin, micode) and understand both sides: how AI generates code and why it breaks.
https://blog.vtemian.com/
Costea Adrian
Embedded Engineer specilizing in perception systems. Latest project was a adas camera calibration system.
Alvin Voo
I’ve watched the tech landscape evolve over the last decade—from the structured days of Java Server Pages to the current "wild west" of Agentic-driven development. While AI can "vibe" a frontend into existence, I specialize in the architecture that keeps it from collapsing.
My expertise lies in the critical backend infrastructure: the parts that must be fast, secure, and scalable. I thrive on high-pressure environments, such as when I had only three weeks to architect and launch an Ethereum redemption system with minimal prior crypto knowledge, turning it into a major revenue stream.
What I bring to your project:
Forensic Debugging: I don't just "patch" bugs; I use tools like Datadog and Explain Analyzers to map out bottlenecks and resolve root causes—like significantly reducing memory usage by optimizing complex DB joins.
Full-Stack Context: Deep experience in Node.js and React, ensuring backends play perfectly with mobile and web teams.
Sanity in the Age of AI: I bridge the gap between "best practices" and modern speed, ensuring your project isn't just built fast, but built to last.
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
What is the difference between validation and sanitization?
Validation checks that input meets your requirements (correct format, length, type) and rejects bad input. Sanitization modifies input to remove dangerous content while keeping the data. You should do both: validate first, then sanitize what passes.
Does React protect against XSS automatically?
React's JSX auto-escapes content in curly braces ({variable}), which prevents most XSS. However, using dangerouslySetInnerHTML, creating elements via DOM APIs, or setting href/src attributes with user data can still introduce XSS vulnerabilities.