Claude Code Web - Technical Architecture Overview
Overview
Claude Code Web is Anthropic's browser-based agentic coding assistant that allows developers to delegate coding tasks directly from their browser. Launched in November 2025 as a research preview, it represents a fundamental shift from traditional desktop IDE tools by executing all operations within secure, isolated cloud sandboxes on Anthropic's infrastructure.
Unlike the CLI version that runs locally, Claude Code Web provides:
- Browser-based access - No terminal or local installation required
- Parallel task execution - Run multiple coding jobs simultaneously
- Secure sandbox isolation - gVisor-based kernel-level isolation
- GitHub integration - Direct repository access via OAuth
High-Level Architecture
Core Architecture Components
1. Sandbox Execution Environment
Each Claude Code Web session creates an isolated container with:
2. Security Architecture - gVisor Isolation
Key Security Features:
| Feature | Implementation | Purpose |
|---|---|---|
| Kernel Isolation | gVisor user-space kernel | Prevent direct hardware access |
| Syscall Filtering | Seccomp-BPF (70-80 of 300+ allowed) | Block dangerous operations |
| Network Control | Egress proxy with JWT validation | Restrict outbound connections |
| Filesystem Isolation | Read/write only to working directory | Prevent file system escape |
| Credential Protection | Scoped credentials via proxy | Never expose real tokens |
3. GitHub Integration Flow
Git Proxy Security Model:
- Real OAuth tokens never enter the sandbox
- Scoped credentials are validated per-operation
- Branch restrictions enforced at proxy level
- All git interactions logged and auditable
4. Network Egress Architecture
Task Execution Flow
Parallel Task Execution
Parallel Execution Benefits:
- Run multiple tasks across different repositories
- No additional cost - pay for compute time, not concurrent sessions
- Each sandbox is fully isolated
- Rate limits consumed proportionally
Real-Time Communication
Communication Features:
- Bidirectional WebSocket for real-time updates
- Follow-up comments evaluated every 2-5 seconds
- High-priority abort commands preempt within milliseconds
- Streaming output for long-running tasks
Container Lifecycle
Key Facts (2025)
Usage Statistics
- 115,000+ developers actively using Claude Code
- 195 million lines of code processed weekly
- 10x user growth since May 2025 launch
- 90% of Claude Code itself written by AI
Revenue & Market
- $500M+ annualized revenue from Claude Code
- $130M estimated from Claude Code Web specifically
- Part of Anthropic's $5B annualized revenue
- 5.5x revenue jump with 300% user growth
Technical Specs
- ~7GB universal container image
- 4GB memory limit per sandbox
- 4-hour JWT token expiry
- 84% reduction in permission prompts with sandboxing
Availability
- Pro plan ($20/month)
- Max plans ($100-200/month)
- Team & Enterprise users with premium seats
Use Cases
Security Considerations
Strengths
- Defense in Depth: Multiple isolation layers (gVisor + Seccomp + Network)
- Credential Protection: Real tokens never enter sandbox
- Auditable Operations: All git operations logged at proxy
- Ephemeral Storage: No data persistence after task completion
- Restricted Network: Allowlist-based egress filtering
Considerations
- Trust Model: Code executes on Anthropic infrastructure
- Network Access: Some external access required for packages
- Repository Access: OAuth grants broad repository permissions
- Rate Limits: Parallel tasks consume proportionally more
Comparison: Web vs CLI
| Feature | Claude Code Web | Claude Code CLI |
|---|---|---|
| Execution | Anthropic cloud sandbox | Local machine |
| Security | gVisor + proxy isolation | OS-level sandboxing |
| GitHub Auth | OAuth (scoped proxy) | Personal tokens/SSH |
| Parallel Tasks | Native support | Manual (multiple terminals) |
| Network | Allowlist egress proxy | Full network access |
| Persistence | Ephemeral per-task | Persistent local |
| Mobile Access | Yes (iOS app) | No |
| Offline | No | Yes |
Architecture Principles
Sources
- Claude Code on the web | Anthropic
- Claude Code Docs - On the Web
- Making Claude Code More Secure | Anthropic Engineering
- Claude Code Sandboxing Docs
- How Claude Code is Built | Pragmatic Engineer
- Claude Code Architecture | ZenML
- Claude Code Best Practices | Anthropic
- Claude Code reaches 115,000 developers | PPC Land
- Reverse Engineering Claude's Sandbox