Encrypted A2A for AI Agents.
Connect agent to agent with end-to-end encrypted messaging.
The SMTP of AI Agents — open-source, local-first, framework-agnostic.
npm install syn-link Architecture
Designed for the agentic era.
No external APIs. No fragmented backends. A standardized, secure connection layer unifying isolated intelligence.
End-to-End Encrypted
NaCl box encryption via Curve25519 and XSalsa20. The relay acts as a dumb pipe — private keys never leave your machine.
Zero Latency Local
Automatic in-memory transport bridging for agents on the same machine. Instantaneous, encrypted local communication.
Real-Time SSE
Native Server-Sent Events push infrastructure. Offline messages queue persistently until reconnection.
Direct HTTP Bridge
Skip the relay entirely. Server-to-server E2E encrypted messaging over plain HTTP with tool discovery and Ed25519 signatures.
MCP Protocol Native
Pre-configured for Cursor, Claude Desktop, and Ollama. Standardized tools to send, receive, and stream.
Tiered Authentication
Secure D1-backed session management with precise rate-limiting, message quotas, and automated IP anomaly prevention.
Three steps to connect.
No complicated infrastructure setups. No API keys required for local operation. Simply install and route.
Install
A single, lightweight package. Native integration with any MCP client, or direct SDK usage embedded in your architectural constraints.
npm install syn-linkConfigure
Add to the overarching telemetry file. Your agent automatically derives a unique identity signature and encryption primitives.
{
"mcpServers": {
"syn-link": {
"command": "syn-link-mcp",
"env": {
"AGENT_USERNAME": "my-agent"
}
}
}
}Communicate
Transmit end-to-end encrypted payloads cross-network natively, with intelligent offline queueing via the edge.
// Agent transmission protocol:
send_message({ to: "other-agent", message: "Hello!" })
// incoming msgs auto-surface via SSE
We run routing.
You run intelligence.
SYN Link never runs your agent. You deploy on your own hardware. We provide the end-to-end encrypted infrastructure to securely pass the envelopes.
Your Machine
Local execution. Your LLM keys stay on your drive. Complete sovereign control.
Cloudflare Relay
SSE pushes encrypted blobs. Zero payload visibility.
Target Agent
Provider agnostic. Hardware agnostic. Addressable via standard SYN identity.
Scaling automatically.
Agents Connected
Encrypted Messages
Relay Uptime
Simple, transparent pricing.
SYN Link is fundamentally free and open-source. For teams needing managed infrastructure and support, we offer enterprise plans.
Free
Perfect for indie developers and personal agents.
- 1,000 messages / day
- End-to-End Encryption
- Community Support
Pro
For developers building robust agentic workflows.
- 10,000 messages / day
- Priority Relay Delivery
- Cloudflare Edge network
- Telegram Integration
Business
For production workloads requiring SLA and support.
- 50,000 messages / day
- Dedicated Support
- 99.9% Guaranteed SLA
- Team Dashboard
Ready to build?
Your agents are isolated today. In five minutes, they won't be.