# Designed for the internet of tomorrow

*EVM-compatible infrastructure with payment-first economics*

Radius gives you Ethereum-compatible development patterns with payment-first economics optimized for real-world transaction volume.

## What works out of the box

Most Ethereum development workflows transfer directly to Radius.

| Tool                     | Status                                   |
| ------------------------ | ---------------------------------------- |
| **Solidity**             | Fully supported (validated up to Prague) |
| **WAGMI**                | Compatible                               |
| **viem**                 | Compatible                               |
| **OpenZeppelin**         | Compatible                               |
| **Foundry**              | Compatible                               |
| **Standard precompiles** | Compatible (validated up to Prague)      |

## What differs from Ethereum

Radius is EVM compatible, but it makes deliberate tradeoffs for payment workloads.

### Use fixed, predictable fees

Ethereum fees change with demand. Radius uses fixed gas pricing so costs remain predictable.

| Ethereum                 | Radius                                |
| ------------------------ | ------------------------------------- |
| Fee market bidding       | Fixed gas pricing                     |
| `eth_gasPrice` varies    | `eth_gasPrice` returns 9.85998816e-10 |
| Cost planning is dynamic | Cost planning is deterministic        |

A standard transaction cost is about 0.00010 USD.

### Settle in milliseconds

| Ethereum                      | Radius                       |
| ----------------------------- | ---------------------------- |
| Confirmation-based confidence | Immediate finality           |
| Reorg risk exists             | No reorg model               |
| Minutes to high confidence    | Millisecond-scale settlement |

### Use stablecoin-native fee flow

| Ethereum                       | Radius                                  |
| ------------------------------ | --------------------------------------- |
| Must hold ETH for fees         | Fees paid in RUSD                       |
| Separate gas-asset requirement | Stablecoin-native flow for payment apps |
| Volatile fee asset             | Stable-value fee model                  |

## Contract implications

### Keep standard Solidity patterns

Your existing contract logic and ERC standards work as expected.

```solidity
IERC20(token).transfer(recipient, amount);

mapping(address => uint256) balances;
balances[msg.sender] = 100;

emit Transfer(from, to, amount);
```

### Avoid assumptions tied to Ethereum-native balance semantics

Prefer explicit token accounting over patterns that assume ETH-style native balance behavior inside contract logic.

```solidity
// Prefer token-based accounting checks in payment flows.
require(IERC20(feeToken).balanceOf(address(this)) > 0);
```

## Data integrity model

Radius prioritizes deterministic execution and replicated operation:

* Three-node clusters provide fault tolerance
* Replication preserves data durability
* Deterministic execution preserves consistency

This model is designed for high-throughput payment infrastructure.

## Why this matters for modern applications

### AI and machine-to-machine payments

Autonomous systems need low-latency settlement for API calls, inference, and compute usage. Radius supports this with:

* Instant settlement
* Sub-cent transaction costs
* Stable-value fee economics

### Micropayment business models

Low predictable cost unlocks:

* Per-request API billing
* Pay-per-visit content
* Streaming payments for compute and bandwidth

## EIP support

Radius tracks Prague support through Revm 33.1.0.

| EIP      | Support                                    |
| -------- | ------------------------------------------ |
| EIP-7702 | Supported                                  |
| EIP-1559 | Supported (adapted to fixed-fee economics) |
| EIP-2930 | Supported                                  |
| EIP-4844 | Supported                                  |

## Precompiles

| Address range   | Precompile set                |
| --------------- | ----------------------------- |
| `0x01` - `0x0a` | Standard Ethereum precompiles |
| `0x4Db27Fa...`  | Radius Edge extensions        |
| `0x07a2bA2...`  | Debug utilities               |

## Network configuration

| Parameter       | Value                               |
| --------------- | ----------------------------------- |
| Network Name    | Radius Testnet                      |
| RPC URL         | https\://rpc.testnet.radiustech.xyz |
| Chain ID        | 72344                               |
| Currency Symbol | RUSD                                |

## Next steps

* [Ethereum compatibility](/reference/ethereum-compatibility.md) — Behavior differences and RPC constraints that affect production systems
* [Network and RPC](/reference/network.md) — Endpoints, chain IDs, and integration setup
* [Fees](/reference/fees.md) — Fee model and the Turnstile behavior