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XChain Platform Action - DEPLOY

This action deploys a smart contract to the XChain VM. Two formats:

  • v0 — standard deployment. Non-stakeable.
  • v1 — stakeable-contract deployment. Adds COOLDOWN_BLOCKS + SLASH_DESTINATION metadata so the contract can accept STAKE v3 actions targeting it.

PARAMS

Name Type Description
VERSION String Format Version (0 = standard, 1 = stakeable)
CODE_ENCODING String Hex-encoded UTF-8 contract source code
GAS_LIMIT Integer Maximum gas units allowed for deployment
CONSTRUCTOR_PARAMS String Optional constructor parameters (pipe-delimited in v0; single field in v1)
COOLDOWN_BLOCKS Integer v1 only — unstaking cooldown for STAKE v3 against this contract (1…100000)
SLASH_DESTINATION String v1 only — address that receives slashed stake. Pass BURN to send to the chain’s configured burn address. Optional — defaults to BURN if COOLDOWN_BLOCKS is set without a destination.

Formats

Version 0 — Standard (non-stakeable)

  • VERSION|CODE_ENCODING|GAS_LIMIT|CONSTRUCTOR_PARAMS

Version 1 — Stakeable contract

  • VERSION|CODE_ENCODING|GAS_LIMIT|CONSTRUCTOR_PARAMS|COOLDOWN_BLOCKS|SLASH_DESTINATION
  • Both staking fields are optional in the wire format. A v1 DEPLOY with empty COOLDOWN_BLOCKS is treated the same as a v0 deploy (the contract is not stakeable). SLASH_DESTINATION without COOLDOWN_BLOCKS is rejected as invalid: SLASH_DESTINATION (requires COOLDOWN_BLOCKS).

Examples

DEPLOY|0|<hex_code>|200000|arg1|arg2
Deploy a non-stakeable contract with constructor arguments

DEPLOY|0|<hex_code>|100000|
Deploy a non-stakeable contract with no constructor parameters

DEPLOY|1|<hex_code>|200000||1000|BURN
Deploy a stakeable contract: 1000-block cooldown on STAKE v3 unstakes,
slashed tokens go to the chain's burn address

DEPLOY|1|<hex_code>|200000||100|bc1q...recipient
Deploy a stakeable contract: 100-block cooldown, slashed tokens routed
to a specific recipient address (not BURN)

Rules

  • Available on all chains
  • CODE_ENCODING must be valid hex-encoded UTF-8 JavaScript source code and must not exceed 64KB (65536 bytes decoded)
  • GAS_LIMIT must be a positive integer
  • The VM validates syntax before charging gas:
    1. V8 compilation check — rejects JavaScript syntax errors
    2. Acorn metering pass — rejects syntax beyond ES2020 (the supported syntax set)
    3. Reserved identifier check — rejects code containing __gas (reserved for gas metering)
  • If syntax validation fails, the deployment is rejected with invalid: CODE_ENCODING (<reason>) and no gas is charged
  • A non-blocking float usage warning is generated if decimal number literals are detected (visible in the execution record)
  • A gas fee is charged at deployment: VM_DEPLOY_BASE + (code_bytes * VM_DEPLOY_PER_BYTE)
  • SOURCE address must hold sufficient XCHAIN tokens to cover the gas fee
  • If CONSTRUCTOR_PARAMS is provided, the VM executes the contract’s initialize method immediately after deployment:
    • Constructor gas is added to the deployment gas: total_gas = deploy_gas + constructor_gas
    • If the constructor fails (reverts, out of gas, etc.), the entire deployment is rolled back — the contract is not stored
    • The caller pays the combined gas even on constructor failure
  • A derived address is created for the contract in the format C:<CHAIN>:<ACTION_INDEX> (e.g., C:BTC:500). This address participates in the standard balance system for token custody via DEPOSIT/WITHDRAW.

Stakeable contracts (v1 staking fields)

  • COOLDOWN_BLOCKS must be an integer in [1, 100000]. Sets the unstaking cooldown for STAKE v3 actions against this contract (overrides the global STAKING.COOLDOWN_BLOCKS for v3 unstakes on this contract).
  • SLASH_DESTINATION accepts either an address (must be valid on the deploying chain) or the literal sentinel BURN. The sentinel resolves to the chain’s configured burn address.
  • If COOLDOWN_BLOCKS is set but SLASH_DESTINATION is empty, the indexer defaults SLASH_DESTINATION to the chain’s burn address.
  • A contract deployed with both staking fields can receive STAKE v3 actions targeting it; without them, STAKE v3 rejects with invalid: TARGET_CONTRACT_INDEX (contract is not stakeable).
  • Stakeable-contract metadata is immutable after deployment — there is no mechanism to update COOLDOWN_BLOCKS or SLASH_DESTINATION later.

Notes

  • The deployed contract is assigned an action index derived from the transaction that contains this action
  • CODE_ENCODING is hex-encoded UTF-8 — decode with Buffer.from(hex, 'hex').toString('utf8')
  • The contracts table stores the decoded plain-text JavaScript, not the hex encoding
  • The api_version field (default 1) determines which gateway API version the contract targets
  • Use EXECUTE to call methods on a deployed contract
  • Use DEPOSIT and WITHDRAW to transfer token balances into and out of the contract’s derived address
  • Deployed contracts are immutable — there is no mechanism to update code after deployment
  • VM_DEPLOY_BASE and VM_DEPLOY_PER_BYTE constants are defined in the gas schedule configuration

Copyright © 2025–2026 Dankest, LLC

Based on XChain Platform by Dankest, LLC – https://dankest.llc

Licensed under the GNU Affero General Public License v3.0 (AGPL-3.0-or-later) with a commercial license available for proprietary use.

You may use, modify, and distribute this material under the terms of the License. See LICENSE and NOTICE for full terms. See the licensing overview.

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