**Purpose:** Single reference for the correct LINK token address per chain. Use these in `.env`, scripts, and UIs so CCIP fee payments and approvals use the proper contract.
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## Chain 138 (Defi Oracle Meta Mainnet)
| Variable | Address | Notes |
|----------|---------|------|
| `LINK_TOKEN` | `0xb7721dD53A8c629d9f1Ba31a5819AFe250002b03` | Deployed on Chain 138; used for CCIP fees |
| `LINK_TOKEN_CHAIN138` | Same as above | Alias for scripts that distinguish by chain |
| `CCIP_FEE_TOKEN` | Same as above | Fee token set on CCIPWETH9/CCIPWETH10 bridges |
**Do not** use Ethereum Mainnet LINK (`0x514910771AF9Ca656af840dff83E8264EcF986CA`) when running scripts or contracts on Chain 138 — that address has no code on 138.
| `MAINNET_LINK_TOKEN` / `CCIP_ETH_LINK_TOKEN` | `0x514910771AF9Ca656af840dff83E8264EcF986CA` | Canonical Chainlink LINK on Mainnet |
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## Other chains (CCIP)
Use [Chainlink CCIP Supported Networks](https://docs.chain.link/ccip/supported-networks) for official LINK addresses. In this repo, per-chain env vars follow the pattern `CCIP_<CHAIN>_LINK_TOKEN` (e.g. `CCIP_BSC_LINK_TOKEN`, `CCIP_POLYGON_LINK_TOKEN`). See `smom-dbis-138/.env` and [fund-ccip-bridges-with-link.sh](../../smom-dbis-138/scripts/deployment/fund-ccip-bridges-with-link.sh).
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## Script defaults
- **Chain 138:** Scripts that run on 138 (e.g. `check-link-balance.sh`, `wrap-and-bridge-weth9-to-mainnet.sh` when approving LINK on 138) must default to `0xb7721dD53A8c629d9f1Ba31a5819AFe250002b03` when `LINK_TOKEN_CHAIN138` / `LINK_TOKEN_138` is unset.
- **Mainnet:** Scripts that run on Mainnet should use `0x514910771AF9Ca656af840dff83E8264EcF986CA` when a mainnet LINK default is needed.
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## Quick check
To confirm the bridge fee token on Chain 138 (should match LINK above):
