Offline Signer CLI: How to Sign Solana Transactions Without Ever Touching the Internet

Offline Signer CLI: How to Sign Solana Transactions Without Ever Touching the Internet

High-value Solana operations have an ugly truth problem: your private key usually lives on an internet-connected machine. That’s fine for coffee-money wallets. It’s reckless for validators, treasuries, DAOs, or anyone moving real value.

That’s exactly the gap the Offline Signer CLI we built aims to close.

This tool lets you construct transactions online, sign them completely offline, and broadcast them later—without hacks, duct tape, or praying your blockhash doesn’t expire.

The problem (a.k.a. why “standard” wallets are not enough)

1. Private keys + internet = unnecessary risk

Most Solana workflows assume your signing key is on a connected machine. That’s an attack surface you don’t need—especially for:

  • Validator operations
  • Treasury movements
  • Multisig or DAO-controlled funds
  • Long-term cold storage

If the machine is online, your key is one exploit away from being gone.

2. Solana’s short transaction lifetime breaks offline signing

Solana relies on a recentBlockhash that expires in ~1–2 minutes. That makes classic air-gapped signing workflows borderline unusable:

Build transaction online → Move it offline → Sign → Move it back → Blockhash expired

Most “offline” guides quietly ignore this problem. The network does not.

The Solution: Offline Signer CLI

The Offline Signer CLI fixes both issues properly. It is a secure, standalone command-line executable for executing sensitive Solana transactions without exposing your private key to the internet. Here is how it works.

1/ Durable Nonces (the real unlock)

Instead of relying on a short-lived blockhash, the CLI uses Durable Nonce accounts. This allows you to:

  • Construct a transaction online;
  • Sign it offline;
  • Broadcast it hours or days later;
  • With zero risk of expiration.

This is how offline signing should work on Solana.

2/ True air-gapped workflow

  • The signer runs on a machine with no internet connection;
  • Your private key never touches an online device;
  • No browser wallets, no RPC calls, no background telemetry.

Cold means cold.

Why this CLI Is different (and better)

Single standalone executable

No Node.js. No npm libraries. No dependency hell.

Just one binary you can run on:

  • An offline laptop
  • A locked-down server
  • A USB-booted machine

If you can execute a file, you can sign securely.

Security Features That Actually Matter

  • True cold storage: Your private key never leaves the offline machine. Period.
  • Versioned transactions: Fully compatible with modern Solana features:
    • Address Lookup Tables
    • Current network standards
  • No legacy compromises.
  • Visual verification before signing: Before you approve anything, the CLI decodes and displays: amount; recipient; network
  • Hot/cold separation: The create-nonce command separates roles cleanly:
    • Payer → hot wallet
    • Authority → cold wallet

You don’t even need your private key online to set things up.

  • Human-readable inputs: The CLI handles decimal math for you, eliminating:
    • Raw unit mistakes
    • Off-by-a-few-zeros disasters
    • “Why did I send 1,000 SOL instead of 1?” moments

Who is this for

If you’re:

  • A validator managing operational funds;
  • A DAO handling treasury movements;
  • A custodian or infra operator; or
  • Anyone who treats private keys as nuclear material,

then this tool should be in your security stack.

Get started now

The Offline Signer CLI is open source and available here:

👉 Offline Signer CLI by Chainflow

No hype. No magic. Just a proper, Solana-native answer to offline signing.