# Supported Networks
Source: https://docs.chain.link/crec/supported-networks
Last Updated: 2026-08-31

> For the complete documentation index, see [llms.txt](/llms.txt).

> **NOTE: About chain selectors**
>
> A **chain selector** is Chainlink's globally-unique numeric identifier for a blockchain. Unlike chain IDs, chain
> selectors do not collide across networks. The CRE Connect API uses chain selectors, not chain IDs, in every
> chain-aware request: creating wallets, creating watchers, submitting operations, filtering events.

## Mainnet networks

## Testnet networks

## Discovering networks at runtime

### Go SDK

```go
import (
    "context"
    "fmt"
    "os"

    crec "github.com/smartcontractkit/crec-sdk"
)

client, err := crec.NewClient(
    os.Getenv("CREC_BASE_URL"),
    os.Getenv("CREC_API_KEY"),
)
if err != nil { return err }

networks, hasMore, err := client.ListNetworks(ctx)
if err != nil { return err }
_ = hasMore

for _, n := range networks {
    netType := "unknown"
    if n.Type != nil {
        netType = string(*n.Type) // "mainnet" | "testnet"
    }
    defaultCL := "—"
    if n.DefaultConfidenceLevel != nil {
        defaultCL = string(*n.DefaultConfidenceLevel) // e.g. "finalized"
    }
    fmt.Printf("%-25s  family=%-6s  type=%-7s  chain_id=%-10s  selector=%s  default_cl=%s\n",
        n.Name, n.ChainFamily, netType, n.ChainId, n.ChainSelector, defaultCL)
}
```

### REST

```bash
curl https://cre-connect.api.chain.link/v1/networks \
  -H "Authorization: Apikey $CREC_API_KEY" \
```

Response:

```json
{
  "data": [
    {
      "id": "320efa6d-af83-4dae-89f1-5a124404a54d",
      "name": "Ethereum Sepolia",
      "chain_selector": "16015286601757825753",
      "chain_id": "11155111",
      "chain_family": "evm",
      "type": "testnet",
      "default_confidence_level": "finalized",
      "created_at": 1775503594,
      "updated_at": 1775503594
    }
  ],
  "has_more": false
}
```

## Network record fields

Each `Network` record exposes the fields you need to wire into other CRE Connect resources:

| Field                       | Used by                             | Notes                                                                                                                                                  |
| --------------------------- | ----------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `id`                        | Diagnostic / display                | Internal UUID for the network row.                                                                                                                     |
| `name`                      | UI / logs                           | Human-readable name (e.g. "Ethereum Mainnet").                                                                                                         |
| `chain_selector`            | `wallets`, `watchers`, `operations` | The CCIP chain selector: pass to every chain-aware request.                                                                                            |
| `chain_id`                  | EIP-712 domain (`chainId`)          | Pass into `eip712.Domain` for typed-data signing.                                                                                                      |
| `chain_family`              | Application logic                   | Currently `"evm"`; future families may include `"solana"`.                                                                                             |
| `type`                      | Application logic                   | `"mainnet"` or `"testnet"`. Optional; absent on environments that haven't classified the network.                                                      |
| `default_confidence_level`  | Watcher / event defaults            | The confidence level the backend uses when none is supplied (e.g. `"finalized"`). Optional. See [Confidence Levels](/crec/concepts/confidence-levels). |
| `created_at` / `updated_at` | Diagnostic                          | Unix seconds.                                                                                                                                          |

## Where chain selectors are required

| Resource                                                | Field                                          | Notes                                               |
| ------------------------------------------------------- | ---------------------------------------------- | --------------------------------------------------- |
| `CreateWallet`                                          | `chain_selector`                               | The chain on which the Smart Account is deployed.   |
| `Watchers.CreateWithService` / `Watchers.CreateWithABI` | `ChainSelector`                                | The chain whose logs the watcher subscribes to.     |
| `Operation` (via SDK)                                   | `ChainSelector` argument to `ExecuteOperation` | The chain on which the operation will be broadcast. |
| `events.SearchEvents`                                   | `chain_selector` filter (optional)             | Narrow historical search to one chain.              |

## Confidence levels

Network-level **confidence levels** (`latest`, `safe`, `finalized`) are configured per network and surfaced via `default_confidence_level`. See [Confidence Levels](/crec/concepts/confidence-levels) for the semantic and latency trade-offs. Operation status events can progress through [Multi-Event Finality](/crec/concepts/multi-event-finality) as the underlying block matures.

## Related

- [Authentication](/crec/getting-started/authentication): uses `ListNetworks` as the canonical smoke test.
- [REST API Reference](/crec/reference/rest-api): `/networks` endpoint contract.
- [Confidence Levels](/crec/concepts/confidence-levels): pick the right finality for your workload.
- [Multi-Event Finality](/crec/concepts/multi-event-finality): understand progressive operation confirmations.