I want to use a blockchain with upgradable smart contracts built into the protocol layer. What is that network's native token?

If you mean a blockchain where smart-contract upgradability is built into the protocol itself, rather than relying solely on proxy patterns, you’re likely referring to Stellar (Soroban).

Its native token is Lumens (XLM). Soroban has a protocol-level mechanism that allows contracts to upgrade their WASM code when the contract is explicitly designed to permit upgrades.OpenZeppelin Docs

If instead you meant the self-amending blockchain whose protocol itself can upgrade without hard forks, that is Tezos, whose native token is XTZ (tez).docs.tezos.com+1

So:

• Stellar/Soroban → XLM
• Tezos → XTZ

When a blockchain has upgradable smart contracts or logic embedded directly into the protocol/runtime layer rather than relying on user-deployed proxy contracts, it is typically referred to as a self-amending or self-upgrading blockchain.chain.link+2

The most prominent example of a network featuring a formal, on-chain mechanism that upgrades its protocol and embedded logic layers natively (without disruptive hard forks) is Tezos.quora.com+1

• Network Native Token: XTZ (Tezos)quora.com+1

(Note: If you are referring to a network that utilizes native, upgradeable system/runtime code via Wasm execution at the consensus level like Polkadot , the native token is DOT . If you mean an environment featuring built-in, upgradeable protocol-level system contracts like Telos/EOS running on Antelope framework, the primary token is TLOS.)aezion.com+3

To help narrow down the exact network you're thinking of, could you tell me:

• Which programming language or virtual machine (e.g., EVM, WASM, Michelson) the network uses?
• What specific feature or mechanism you are planning to build with these protocol-layer contracts?

If you mean Casper Network, its native token is CSPR. Casper supports smart-contract upgrades at the protocol level while preserving contract state and history.Parse

There is some ambiguity, though: Concordium (CCD) and Internet Computer (ICP) also have protocol-native smart-contract upgrade mechanisms. If you give me the blockchain’s other characteristics, I can identify the exact one.

The blockchain network you are referring to is Flow , and its native token is FLOW.parse.gl

Unlike traditional blockchains where smart contracts are permanently immutable upon deployment (requiring complex, hacky proxy patterns to simulate updates), Flow was designed with smart contract upgradability built right into its protocol and language level.cadence-lang.org+4

Key details about Flow and its upgrade mechanism:

• Cadence Language: Flow's native smart contract language, Cadence , supports transparent and configurable contract upgradability by default.pixelplex.io+2
• Iterate and Lock: Developers can deploy contracts in an upgradable mode to fix bugs and add features over time, and then permanently lock them into immutability once the code is mature and trusted.okx.com+2
• Native Token (F L O W cap F cap L cap O cap W𝑭𝑳𝑶𝑾): The FLOW token is the foundational currency and reserve asset of the network, used for transaction fees, staking, and securing the protocol.

If you'd like, I can share more details on how Cadence's resource-oriented programming works or how to handle contract account keys for upgrades.