# Token Mapping and Mainnet Addresses (Chain 138 ↔ Ethereum Mainnet)

**Last Updated:** 2026-02-13  
**Status:** Active  
**Source of truth:** `config/token-mapping.json`

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## Overview

Ethereum Mainnet (chainId 1) in `config/smart-contracts-master.json` lists only **CCIP relay contracts plus canonical WETH9 and LINK**. It does **not** include wrapped/mirrored ERC‑20 addresses for tokens that originate on Chain 138 (e.g. Compliant USDT/USDC, WETH10). This document defines the full mapping and how to use it.

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## Definitive Mainnet Addresses (from source of truth)

| Token | Mainnet address | Notes |
|-------|-----------------|--------|
| **WETH9** (canonical) | `0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2` | Same on Chain 138; only token the current Mainnet CCIPRelayBridge accepts. |
| **LINK** (canonical) | `0x514910771AF9Ca656af840dff83E8264EcF986CA` | Canonical Mainnet LINK; relay bridge does **not** accept LINK yet (WETH9-only). |

For any other token (USDT, USDC, WETH10, etc.) the JSON and the Mainnet bridge do **not** specify a Mainnet “bridged” contract. Mainnet canonical references (for documentation only) are in `config/token-mapping.json` under `mainnetCanonicalReference`.

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## Full mapping table (Chain 138 → Mainnet)

| Token key | Chain 138 address | Mainnet address | Relay supported (138→Mainnet) |
|-----------|-------------------|-----------------|-------------------------------|
| WETH9 | `0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2` | `0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2` | ✅ Yes |
| LINK_Token | `0xb7721dD53A8c629d9f1Ba31a5819AFe250002b03` | `0x514910771AF9Ca656af840dff83E8264EcF986CA` | ❌ No (bridge WETH9-only) |
| WETH10 | `0xf4BB2e28688e89fCcE3c0580D37d36A7672E8A9f` | — | ❌ No |
| Compliant_USDT | `0x93E66202A11B1772E55407B32B44e5Cd8eda7f22` | — | ❌ No |
| Compliant_USDC | `0xf22258f57794CC8E06237084b353Ab30fFfa640b` | — | ❌ No |
| Tether_USDT_Chain138 | `0x15DF1D5BFDD8Aa4b380445D4e3E9B38d34283619` | — | ❌ No |

“—” means no Mainnet wrapped/mirrored contract in the current design; the Mainnet CCIPRelayBridge has no token registry or factory for these.

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## Where mapping is used

- **Relay service** (`smom-dbis-138/services/relay`): `config.js` builds `tokenMapping` (Chain 138 address → Mainnet address) from `config/token-mapping.json` when available, otherwise uses a fallback object. Only WETH9 is accepted by the Mainnet bridge; LINK is mapped for future use.
- **Config:** `config/token-mapping.json` is the single source of truth. `config/token-mapping-loader.cjs` provides `getRelayTokenMapping()` and `getTokenList()` for consumers.

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## Mainnet bridge behaviour

- **CCIPRelayBridge** (Mainnet): `0xF9A32F37099c582D28b4dE7Fca6eaC1e5259f939`
  - Accepts only **WETH9** (`message.tokenAmounts[0].token == weth9`).
  - No view functions such as `getWrappedToken(originChainId, originToken)` or `nativeToWrapped(...)`.
  - No on-chain token registry; no wrapped token deployment for Chain 138–origin tokens.
- **Getting Mainnet token address** for a bridged token:
  - **WETH9:** use `0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2`.
  - **LINK:** use `0x514910771AF9Ca656af840dff83E8264EcF986CA` (canonical); relay bridge does not support it yet.
  - **Anything else:** not derivable from the current bridge or JSON; would require a different Mainnet contract that deploys/registers wrapped tokens and exposes a mapping.

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## Recommendations and suggestions

1. **Keep `config/token-mapping.json` as the single source of truth**  
   Add or change token entries there; the relay and docs should reference it. When adding a new token with a Mainnet address, set `mainnetAddress` and `relaySupported` as appropriate.

2. **Extend Mainnet bridge for LINK (optional)**  
   To support 138→Mainnet LINK via the relay, either:
   - Extend CCIPRelayBridge to accept LINK (and hold/fund LINK), or
   - Deploy a separate receiver contract for LINK and point relay to it for LINK messages.  
   After that, set `relaySupported: true` for LINK in `token-mapping.json`.

3. **Document unsupported tokens**  
   WETH10, Compliant_USDT, Compliant_USDC, and Tether_USDT_Chain138 have no Mainnet wrapped address in this design. For token lists or UIs, use this doc or `token-mapping.json` so integrators do not assume a Mainnet address exists.

4. **If you introduce wrapped tokens on Mainnet later**  
   If a future bridge or TokenFactory deploys wrapped tokens on Mainnet for Chain 138 assets:
   - Add the Mainnet wrapped address to `config/token-mapping.json` for that token.
   - If the relay will deliver that token, add the Chain 138 → Mainnet mapping to the relay’s `tokenMapping` (already driven by `token-mapping.json` when the config path is available).
   - Optionally add the wrapped contract to `config/smart-contracts-master.json` under chain 1 if you want it in the main contract list.

5. **Canonical Mainnet references (reference only)**  
   For documentation and off-chain tooling, canonical Mainnet addresses are in `config/token-mapping.json` under `mainnetCanonicalReference` (e.g. USDT, USDC, WETH9, LINK). These are not “bridged” addresses from Chain 138 unless explicitly mapped in `tokens`.

6. **Relay service**  
   When running the relay from the monorepo, ensure `config/token-mapping.json` and `config/token-mapping-loader.cjs` are available so the relay uses the full mapping. Fallback in `config.js` covers WETH9 and LINK when the config is not present.

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## Additional recommendations

7. **CI validation**  
   The pipeline runs `scripts/validation/validate-config-files.sh` when `config/` changes. That script checks for `config/token-mapping.json` and, if present, validates that it is valid JSON with a `.tokens` array. Keep the file valid so CI passes.

8. **Sync when adding tokens**  
   When adding a new token to Chain 138 (or a new bridged token), update both:
   - `config/smart-contracts-master.json` (under `chains.138.contracts` if it is a contract),
   - `config/token-mapping.json` (add an entry with `key`, `chain138Address`, `mainnetAddress` if known, `relaySupported`, `notes`).  
   Optionally update [CHAIN138_TOKEN_ADDRESSES.md](../11-references/CHAIN138_TOKEN_ADDRESSES.md) and the cross-chain table there.

9. **Runbook for LINK support**  
   To enable 138→Mainnet LINK delivery, follow [RELAY_BRIDGE_ADD_LINK_SUPPORT_RUNBOOK.md](RELAY_BRIDGE_ADD_LINK_SUPPORT_RUNBOOK.md) (extend bridge or deploy separate LINK receiver, then set `relaySupported: true` for LINK in `token-mapping.json`).

10. **Token lists and UIs**  
    When building token lists or UIs that show “Mainnet address” or “bridged address” for Chain 138 tokens, read from `config/token-mapping.json` or this doc. Do not assume every Chain 138 token has a Mainnet address; only WETH9 is relay-supported today; LINK has a canonical Mainnet address but is not yet relay-supported.

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## Multi-chain mapping (138↔651940, 651940↔other chains)

For **138↔651940** and **651940↔56, 137, 100, 43114, 8453, 42161, 10, 25, 1**, use `config/token-mapping-multichain.json`. The same loader provides:

- `getTokenMappingForPair(fromChainId, toChainId)` — returns `{ tokens, addressMapFromTo, addressMapToFrom }`.
- `getAllMultichainPairs()` — list of defined chain pairs.
- `getMappedAddress(fromChainId, toChainId, tokenAddress)` — resolve token address on target chain.

See [MAPPER_COVERAGE_BRIDGES_AND_LIQUIDITY_POOLS.md](MAPPER_COVERAGE_BRIDGES_AND_LIQUIDITY_POOLS.md). To verify canonical token addresses per chain, use the explorer token lists in [EXPLORER_TOKENS_CANONICAL_MAPPING.md](EXPLORER_TOKENS_CANONICAL_MAPPING.md).

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## References

- [CCIP_BRIDGE_MAINNET_CONNECTION.md](CCIP_BRIDGE_MAINNET_CONNECTION.md) — Relay flow and mainnet contracts.
- [RELAY_BRIDGE_ADD_LINK_SUPPORT_RUNBOOK.md](RELAY_BRIDGE_ADD_LINK_SUPPORT_RUNBOOK.md) — Optional runbook to add LINK support to the Mainnet relay bridge.
- [MAPPER_COVERAGE_BRIDGES_AND_LIQUIDITY_POOLS.md](MAPPER_COVERAGE_BRIDGES_AND_LIQUIDITY_POOLS.md) — Mapper and multichain token mapping coverage.
- [CHAIN138_TOKEN_ADDRESSES.md](../11-references/CHAIN138_TOKEN_ADDRESSES.md) — Chain 138 token list.
- `config/token-mapping.json` — 138↔Mainnet machine-readable mapping.
- `config/token-mapping-multichain.json` — 138↔651940 and 651940↔CCIP/canonical chains.
- `config/token-mapping-loader.cjs` — Loader API for relay and multichain tooling.
- [EXPLORER_TOKENS_CANONICAL_MAPPING.md](EXPLORER_TOKENS_CANONICAL_MAPPING.md) — Explorer tokens/contracts list URLs for verifying canonical addresses per chain.