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Overview

The tenderly devnet spawn-rpc command creates a JSON-RPC endpoint for your DevNet, allowing you to connect development tools, frameworks, and scripts to your local blockchain development environment.

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Usage

tenderly devnet spawn-rpc [flags]

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Description

This command spawns a DevNet RPC endpoint that represents the JSON-RPC interface for your development blockchain. The RPC endpoint can be used with tools like Hardhat, Foundry, web3.js, ethers.js, and other Ethereum development frameworks.
A template must be specified when spawning a DevNet RPC. Templates define the initial configuration and state of your development network.

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Flags

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Required Flags

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--template
string
required
The DevNet template slug to apply when spawning the DevNet RPC. Templates define the network configuration and initial state.
tenderly devnet spawn-rpc --template mainnet-fork

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Optional Flags

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--account
string
The Tenderly account username or organization slug. If not provided, the system reads account_id from tenderly.yaml.
tenderly devnet spawn-rpc --account my-org --template my-template
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--project
string
The DevNet project slug. If not provided, the system reads project_slug from tenderly.yaml.
tenderly devnet spawn-rpc --project my-project --template my-template
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--access_key
string
The Tenderly access key for authentication. If not provided, the system reads access_key from tenderly.yaml or uses the stored authentication token.
tenderly devnet spawn-rpc --access_key your-access-key --template my-template
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--token
string
The Tenderly JWT token for authentication. If not provided, the system reads token from tenderly.yaml or uses the stored authentication.
tenderly devnet spawn-rpc --token your-jwt-token --template my-template
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--return-url
boolean
default:"false"
Return only the URL without additional logging output. Useful for scripting and automation.
tenderly devnet spawn-rpc --template my-template --return-url

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Examples

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Basic Usage

Spawn a DevNet RPC using a template with default project settings from tenderly.yaml: 
tenderly devnet spawn-rpc --template mainnet-fork

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Specify Account and Project

Explicitly set the account and project for the DevNet: 
tenderly devnet spawn-rpc \
  --account my-organization \
  --project defi-testing \
  --template uniswap-v3-fork

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Use Access Key Authentication

Spawn a DevNet with explicit access key authentication: 
tenderly devnet spawn-rpc \
  --access_key TENDERLY_ACCESS_KEY \
  --template custom-network \
  --project smart-contract-dev

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Return URL for Scripting

Get only the RPC URL for use in scripts or CI/CD pipelines: 
RPC_URL=$(tenderly devnet spawn-rpc --template mainnet-fork --return-url)
echo "DevNet RPC endpoint: $RPC_URL"

tenderly devnet spawn-rpc --template mainnet-fork

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Authentication

The command requires authentication through one of the following methods (in order of precedence):
1

Command-line Flags

Provide --access_key or --token flags directly in the command.
2

Configuration File

Store credentials in tenderly.yaml configuration file.
3

Login Session

Use credentials from tenderly login command.
For security best practices, avoid hardcoding credentials in scripts. Use environment variables or secure secret management in CI/CD environments.

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Configuration Precedence

When multiple configuration sources are available, the command follows this precedence order:
  1. Command-line flags - Highest priority
  2. tenderly.yaml file - Project-level configuration
  3. Global configuration - From tenderly login session
This allows you to override project defaults on a per-command basis.

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Error Handling

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Missing Template

If the --template flag is not provided: 
Error: Missing required argument 'template'
The 'template' argument is required. Please include the --template flag 
and provide the DevNet template slug.
Solution: Always specify a template when spawning a DevNet RPC.

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Missing Account

If no account is found in flags or configuration: 
Error: account not found
An account is required. Please log in using tenderly login 
or include the '--account' flag.
Solution: Run tenderly login or provide the --account flag.

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Missing Project

If no project is found in flags or configuration: 
Error: project not found
No project was found. To set a project, use tenderly use project <project-slug> 
or include the '--project' flag.
Solution: Set a project with tenderly use project or provide the --project flag.

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Missing Authentication

If neither access key nor token is available: 
Error: access key or token not found
An access key or token is required. Please log in using tenderly login 
or include the '--access_key' or '--token' flag.
Solution: Run tenderly login or provide authentication credentials.

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Use Cases

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Local Development

Spawn a DevNet for local smart contract development: 
# Spawn DevNet with mainnet fork template
tenderly devnet spawn-rpc --template mainnet-fork --return-url > .env.devnet

# Use in your Hardhat config
# hardhat.config.js
require('dotenv').config({ path: '.env.devnet' });

module.exports = {
  networks: {
    devnet: {
      url: process.env.DEVNET_RPC
    }
  }
};

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Integration Testing

Create isolated DevNets for integration tests: 
# test-setup.sh
DEVNET_RPC=$(tenderly devnet spawn-rpc \
  --template test-environment \
  --return-url)

export TEST_RPC_URL=$DEVNET_RPC
npm run test:integration

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Multi-Network Testing

Spawn multiple DevNets for cross-chain testing: 
# Spawn Ethereum DevNet
ETH_RPC=$(tenderly devnet spawn-rpc \
  --template ethereum-mainnet \
  --return-url)

# Spawn Polygon DevNet  
POLY_RPC=$(tenderly devnet spawn-rpc \
  --template polygon-mainnet \
  --return-url)

# Run cross-chain tests
npx hardhat test --network-eth $ETH_RPC --network-poly $POLY_RPC

DevNets Overview

Learn more about Tenderly DevNets

Login

Authenticate with Tenderly

Initialize

Set up a Tenderly project

Configuration

Configure tenderly.yaml

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Next Steps

1

Create a template

Define templates for your common DevNet configurations in the Tenderly Dashboard.
2

Integrate with your framework

Configure your development framework (Hardhat, Foundry, etc.) to use the DevNet RPC endpoint.
3

Automate testing

Add DevNet spawning to your CI/CD pipeline for automated testing.

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