# Supergateway MCP Transport Proxy (supergateway) - AgentBreakWatch Reference

> TL;DR Verdict: Supergateway MCP Transport Proxy (`supergateway`) is currently at v4.2.0 on NPM (published 2026-10-15), with a 90-day Stability Score of 86/100 (B+) and MEDIUM schema drift risk across 3 releases in the last 90 days. v4.x adds stateful/stateless Streamable HTTP output flags (--outputTransport streamableHttp) alongside SSE and WS.

## Live Telemetry Metadata
- Canonical Page: https://agentbreakwatch.vercel.app/p/supergateway
- Category Hub: https://agentbreakwatch.vercel.app/c/mcp-bridges-devtools (MCP Bridges, Transports, Inspectors & Developer Tools)
- Package Name: `supergateway`
- Registry: NPM (https://www.npmjs.com/package/supergateway)
- GitHub Repository: https://github.com/supercorp-ai/supergateway
- Vendor: Supercorp
- Latest Live Version: v4.2.0
- Published Date: 2026-10-15T20:14:13.463Z
- 90-Day Release Count: 3
- Direct Dependencies: 12
- License: MIT
- Stability Score: 86/100 (Grade B+)
- Schema Drift Risk: MEDIUM
- Recommended Exact Pin Command: `npx -y supergateway@4.2.0`
- Watched Symbols / MCP Tools: supergateway
- Snapshot Timestamp: 2026-10-24T12:11:27.697Z

## Breaking Change & Schema Drift Summary
v4.x adds stateful/stateless Streamable HTTP output flags (--outputTransport streamableHttp) alongside SSE and WS.

## Migration Diff: Before (Deprecated / Unpinned Pattern)
```
npx -y supergateway --stdio "npx -y @modelcontextprotocol/server-filesystem ." --port 8000
```

## Migration Diff: After (Verified v4.2.0 Pattern)
```
npx -y supergateway --stdio "npx -y @modelcontextprotocol/server-filesystem ." --outputTransport streamableHttp --port 8000
```

## Recent Verified Releases
- v4.2.0 (published 2026-10-15) [LATEST]
- v4.1.0 (published 2026-09-30)
- v4.0.0 (published 2026-09-20)
- v3.4.3 (published 2025-10-09)
- v3.4.2 (published 2025-10-01)
- v3.4.1 (published 2025-10-01)