siwx

name	siwx
description	CAIP-122 Sign-In with X CLI tool for generating signing messages and verifying signatures across Ethereum and Solana. Use when the user asks to create sign-in challenges, verify wallet signatures, generate nonces, or parse CAIP-122 messages. Supports JSON output via --json flag for agent consumption.

siwx CLI — CAIP-122 Sign-In with X Tool

siwx is a single binary CLI for generating and verifying blockchain sign-in messages following the CAIP-122 standard. Supports Ethereum (EIP-191) and Solana (Ed25519).

Installation

Shell (macOS / Linux):

curl -fsSL https://sh.qntx.fun/siwx | sh

PowerShell (Windows):

irm https://sh.qntx.fun/siwx/ps | iex

Or via Cargo:

cargo install siwx-cli

Verify installation

siwx --version

CLI Structure

siwx [--json] <chain> <subcommand> [options]

The --json flag is global and must appear before the chain subcommand. When set, all output (including errors) is a single JSON object on stdout.

Commands

Command	Description
evm message	Generate an Ethereum CAIP-122 signing message
evm verify	Verify an EIP-191 signature
svm message	Generate a Solana CAIP-122 signing message
svm verify	Verify an Ed25519 signature
nonce	Generate a cryptographic nonce
parse	Parse a CAIP-122 message string into fields

Chain aliases

Chain	Primary	Aliases
Ethereum	evm	eth
Solana	svm	sol

Message Generation Flags

Flag	Required	Description
--domain	✓	RFC 4501 domain requesting the signing
--address	✓	Blockchain address (0x-hex for EVM, base58 for SVM)
--uri	✓	RFC 3986 URI subject of the signing
--chain-id	✓	CAIP-2 chain identifier (e.g. "1" for Ethereum mainnet)
--statement		Human-readable statement
--nonce		Nonce (auto-generated if omitted)
--expiration		Expiration (RFC 3339 timestamp or seconds from now)
--not-before		Not-before time (RFC 3339 or seconds from now)
--request-id		System-specific request ID
--resource		Resource URI (repeatable)
--msg-version		Message version (default: "1")

Verify Flags

Flag	Required	Description
--message	✓	The raw CAIP-122 signing message text
--signature	✓	Hex-encoded signature (0x prefix optional)

Usage Examples

Generate Ethereum signing message (JSON)

siwx --json evm message \
  --domain example.com \
  --address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 \
  --uri https://example.com/login \
  --chain-id 1 \
  --statement "I accept the Terms of Service"

Generate Solana signing message (JSON)

siwx --json svm message \
  --domain example.com \
  --address GwAF45zjfyGzUbd3i3hXxzGeuchzEZXwpRYHZM5912F1 \
  --uri https://example.com/login \
  --chain-id 5eykt4UsFv8P8NJdTREpY1vzqKqZKvdpKuc147dw2N9d

Verify an EIP-191 signature (JSON)

siwx --json evm verify \
  --message "example.com wants you to sign in with your Ethereum account:..." \
  --signature 0x1234abcd...

Verify a Solana Ed25519 signature (JSON)

siwx --json svm verify \
  --message "example.com wants you to sign in with your Solana account:..." \
  --signature abcd1234...

Generate a nonce

siwx --json nonce
siwx nonce --len 32

Parse a message

siwx --json parse --message "example.com wants you to sign in with your Ethereum account:..."

JSON Output Schemas

Message Generation

{
  "chain": "ethereum",
  "message": "example.com wants you to sign in with your Ethereum account:\n0xd8dA...\n\n...",
  "domain": "example.com",
  "address": "0xd8dA...",
  "uri": "https://example.com/login",
  "version": "1",
  "chain_id": "1",
  "nonce": "abc123def456",
  "issued_at": "2026-03-20T12:00:00Z"
}

Verify

{
  "valid": true,
  "chain": "ethereum",
  "domain": "example.com",
  "address": "0xd8dA..."
}

Nonce

{
  "nonce": "M07wdVLtaJVndQAx5",
  "len": 17
}

Parse

{
  "domain": "example.com",
  "address": "0xd8dA...",
  "uri": "https://example.com/login",
  "version": "1",
  "chain_id": "1",
  "nonce": "abc123",
  "issued_at": "2026-03-20T12:00:00Z"
}

Error

All errors in JSON mode return exit code 1 with:

{
  "error": "invalid message format: missing preamble marker"
}

Agent Best Practices

1. Always use --json for programmatic consumption to avoid ANSI escape codes.
2. --json placement: Must appear before the chain subcommand: siwx --json evm message, not siwx evm --json message.
3. Nonce auto-generation: If --nonce is omitted in message, a 17-character cryptographic nonce is auto-generated.
4. Issued-at auto-set: issued_at is always set to the current UTC time.
5. Expiration shorthand: Pass seconds for relative expiration: --expiration 3600 = 1 hour from now.
6. Verify reads address from message: For SVM verify, the public key is derived from the address in the parsed message.
7. Errors in JSON mode return {"error": "..."} with exit code 1.
8. Signature format: Always hex-encoded, 0x prefix is optional.