⚡ API Vault

Local-first API Client & Model Context Protocol (MCP) Server powered by Node.js Native SQLite.
Zero cloud limits, zero data truncation, 100% private, with a high-density developer Web Studio.

💡 Why API Vault?

Traditional cloud-based API clients (Postman, Hoppscotch Cloud) often hit painful ceilings:

• Cloud Document Size Limits: E.g. Hoppscotch Cloud syncs user collections in a single Google Cloud Firestore document with a hard 1MB limit. Large OpenAPI specs, logs, or payload responses silently break sync (user/collection_creation_failed).

• Privacy & Secret Leakage: Internal tokens, staging endpoints, and private corporate data end up on third-party cloud servers.

• Disconnected AI Agents: When coding with Claude Desktop, Cursor, or Antigravity, AI agents cannot easily audit past requests or execute internal API queries without manual curl copying.

API Vault solves this permanently. Built entirely on Node.js 22+ native SQLite (node:sqlite) with zero external npm dependencies, API Vault stores gigabytes of full headers, input bodies, and raw responses locally on your machine, while seamlessly exposing an MCP interface to AI agents and a keyboard-friendly Web Studio for humans.

Related MCP server: RequestBin MCP Server

✨ Features

• 🚀 Zero Size Limits & 100% Local Storage: Every request and response is persistently stored in ~/.api-vault/api_vault.db using Node.js native SQLite. No truncation, no cloud fees.

• 🤖 Native MCP Server: Plug directly into Claude Desktop, Cursor, Antigravity, Cline, and any MCP client.

• 📝 Mandatory AI Purpose Logging: AI agents are required to declare why an endpoint is called (description), keeping an interpretable audit trail of all automated actions.

• 🖥️ Dense Tech Web Studio:

  • Collapsible Multi-Criteria Grouping: Group past requests by Host/Domain, Date, HTTP Status, Method, or Flat view.

  • Smart Endpoint Shortening: Automatically strips verbose schemes and hostnames, applying middle truncation (.../dags/demo/dagRuns) so you can identify resources at a glance.

  • One-Click Toggle (/api & ⊟): Switch between compact paths and full URLs, or expand/collapse all groups instantly.

  • Hover Tooltips: Hover over any shortened endpoint to view the 100% complete URL.

• 🌐 CORS-Free Execution Proxy: Call private VPN hosts, staging microservices, or local Docker services without browser CORS restrictions.

• ⚡ Zero Dependencies: Pure Node.js standard library (node:http, node:sqlite, node:child_process). Instant startup.

🚀 Quickstart

1. Launch the Web Studio

Run one command to start the local proxy and launch the Web Studio in your default browser:

npx api-vault studio

Options:

# Specify custom port (default: 54193)
npx api-vault studio -p 54193

# Specify custom SQLite data directory (default: ~/.api-vault)
API_VAULT_DATA_DIR=/path/to/data npx api-vault studio

2. Run as an MCP Server

To run API Vault as an MCP Stdio Server for your AI assistants:

npx api-vault

🔌 MCP Client Configuration

Claude Desktop

Add this to your claude_desktop_config.json:

{
  "mcpServers": {
    "api-vault": {
      "command": "npx",
      "args": ["-y", "api-vault"]
    }
  }
}

Cursor (mcp.json)

{
  "mcpServers": {
    "api-vault": {
      "command": "npx",
      "args": ["-y", "api-vault"]
    }
  }
}

Antigravity / Gemini CLI (mcp_config.json)

{
  "mcpServers": {
    "api-vault": {
      "command": "node",
      "args": ["/path/to/api-vault/src/server.js"],
      "env": {
        "API_VAULT_PORT": "54193"
      }
    }
  }
}

🛠️ MCP Tools Reference

🏗️ Architecture

                    ┌─────────────────────────────────────┐
                    │      AI Agent / MCP Client          │
                    │  (Claude Desktop, Cursor, Antigravity)│
                    └──────────────────┬──────────────────┘
                                       │ JSON-RPC (stdio)
                                       ▼
┌──────────────────────┐    ┌─────────────────────────────────────┐
│   Developer Browser  │    │         API Vault Engine            │
│  (Dense Tech Studio) │    │                                     │
└──────────┬───────────┘    │  • MCP Server (tools/call)          │
           │ HTTP / SSE     │  • CORS Proxy Bridge                │
           └───────────────►│  • Smart Truncation & Grouping      │
                            └──────────────────┬──────────────────┘
                                               │ node:sqlite
                                               ▼
                                    ┌──────────────────────┐
                                    │    Local SQLite DB   │
                                    │  (~/.api-vault/*.db) │
                                    └──────────────────────┘

📜 License

MIT License © 2026 Vinh Tran. Free and open-source for personal and commercial use.