fix: align examples with tronz updates

CONTRIBUTING.md

@@ -13,6 +13,7 @@ Thanks for your interest in contributing! All contributions are welcome.
 - All examples target the **Nile testnet** by default.
 - Read-only examples must run without any environment variables.
 - Examples that send transactions require `TRON_PRIVATE_KEY=<hex>`.
+- Use `TRON_API_KEY` for optional TronGrid API key support.
 - Use `anyhow::Result<()>` as the return type of `main`.
 - Keep examples focused — one concept per file.
 

Cargo.toml

@@ -5,7 +5,7 @@ resolver = "2"
 [workspace.package]
 version      = "0.1.0"
 edition      = "2024"
-rust-version = "1.85"
+rust-version = "1.90"
 authors      = ["tronz contributors"]
 license      = "MIT OR Apache-2.0"
 homepage     = "https://github.com/throgxyz/examples"

README.md

@@ -4,6 +4,8 @@ Runnable examples for the [tronz](https://github.com/throgxyz/tronz) TRON SDK.
 
 All examples target the [Nile testnet](https://nileex.io). Read-only examples run without a private key; examples that send transactions require `TRON_PRIVATE_KEY=<hex>`.
 
+Set `TRON_API_KEY` to use a TronGrid API key.
+
 ## Usage
 
 ```sh
@@ -14,6 +16,20 @@ cargo run -p examples-queries --example query
 TRON_PRIVATE_KEY=<hex> cargo run -p examples-staking --example stake
 ```
 
+## Environment Variables
+
+| Variable | Description |
+| --- | --- |
+| `TRON_PRIVATE_KEY` | Funded Nile private key for write examples. |
+| `TRON_API_KEY` | Optional TronGrid API key. |
+| `TRON_ADDRESS` | Address to query in read examples. |
+| `TRON_TO` | Recipient or target address in write examples. |
+| `TRON_CONTRACT` | TRC20 or smart contract address. |
+| `TRON_TX_ID` | Transaction id used by receipt/log decoding examples. |
+| `TRON_AMOUNT_SUN` | TRX amount in sun for TRX transfer examples. |
+| `TRON_FREEZE_SUN` | Amount to stake in staking examples. |
+| `TRON_TOKEN_ID` | Numeric TRC10 token id. |
+
 ## Overview
 
 This repository contains the following examples:

clippy.toml

@@ -1 +1 @@
-msrv = "1.85"
+msrv = "1.90"

examples/contracts/examples/contract_call.rs

@@ -12,13 +12,13 @@
 //! No private key required (read-only).
 //!
 //! Required env:
-//!   TRON_CONTRACT — TRC20 contract address (e.g. USDT on mainnet)
+//!   TRON_CONTRACT — TRC20 contract address (e.g. test USDT on Nile)
 //!
 //! Optional env:
 //!   TRON_API_KEY  — TronGrid API key
 //!
 //! ```bash
-//! TRON_CONTRACT=TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t \
+//! TRON_CONTRACT=TXYZopYRdj2D9XRtbG411XZZ3kM5VkAeBf \
 //!   cargo run -p examples-contracts --example contract_call
 //! ```
 

examples/contracts/examples/contract_dynamic_abi.rs

@@ -17,8 +17,8 @@
 //!   TRON_API_KEY  — TronGrid API key
 //!
 //! ```bash
-//! TRON_CONTRACT=TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t \
-//! TRON_ADDRESS=TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t \
+//! TRON_CONTRACT=TXYZopYRdj2D9XRtbG411XZZ3kM5VkAeBf \
+//! TRON_ADDRESS=TXYZopYRdj2D9XRtbG411XZZ3kM5VkAeBf \
 //!   cargo run -p examples-contracts --example contract_dynamic_abi
 //! ```
 

examples/queries/examples/query.rs

@@ -1,4 +1,4 @@
-//! Read-only queries against the TronGrid mainnet.
+//! Read-only queries against the TronGrid Nile testnet.
 //!
 //! No private key required.
 //!
@@ -12,8 +12,7 @@
 
 use tronz::{ProviderBuilder, TRONGRID_NILE, TronProvider, primitives::ResourceCode};
 
-// A well-known TRON address with on-chain activity (USDT TRC20 contract on
-// mainnet; also present on Nile testnet with TRX balance).
+// A well-known TRON address that is present on Nile testnet with TRX balance.
 const DEFAULT_ADDR: &str = "TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t";
 
 #[tokio::main]

examples/signers/examples/signer_generate.rs

@@ -49,7 +49,7 @@ fn main() -> anyhow::Result<()> {
     println!("  2. Get Nile TRX from the faucet: https://nileex.io/");
     println!("     (send to: {address})");
     println!(
-        "  3. Run examples with: TRON_PRIVATE_KEY={key_hex} cargo run -p examples-signers --example transfer_trx"
+        "  3. Run examples with: TRON_PRIVATE_KEY={key_hex} cargo run -p examples-transfers --example transfer_trx"
     );
 
     Ok(())