Configuration

Complete kora.toml configuration reference

Your Kora node will be signing transactions for your users, so it is important to configure it to only sign transactions that meet your business requirements. Kora gives you a lot of flexibility in how you configure your node, but it is important to understand the implications of your configuration. kora.toml is the control center for your Kora configuration. This document provides a comprehensive reference for configuring your Kora paymaster node through the kora.toml configuration file.

Overview

The kora.toml file controls all aspects of your Kora node's behavior including:

Rate limiting and authentication
RPC method availability
Transaction validation rules
Fee pricing models
Security policies
RPC method availability
Fee pricing models
Payment address configuration
Performance monitoring

Your configuration file should be placed in your deployment directory or specified via the --config flag when starting the server.

Configuration Sections

The kora.toml file is organized into sections, each with its own set of options. This guide walks through each section and explains the options available:

Kora Core Policies - Core server settings
Kora Authentication - Authentication settings
Kora Caching - Redis caching for RPC calls
Kora Usage Limits - Per-wallet transaction limiting
Kora Enabled Methods - Kora RPC methods to enable
Validation Policies - Transaction validation and security
Token-2022 Extension Blocking - Block risky Token-2022 extensions
Fee Payer Policy - Restrictions on fee payer wallet
Price Configuration - Transaction fee pricing models
Performance Monitoring - Metrics collection and monitoring
Complete Example - Full production-ready configuration

Sample kora.toml file sections:

[kora]
# Core server settings

[kora.auth]
# Authentication settings

[kora.cache]
# Redis caching configuration

[kora.usage_limit]
# Per-wallet transaction limiting

[kora.enabled_methods]
# Kora RPC methods to enable

[validation]
# Transaction validation rules

[validation.token2022]
# Token-2022 extension blocking

[validation.fee_payer_policy]
# Restrictions on fee payer wallet

[validation.price]
# Transaction fee pricing models

[metrics]
# Performance monitoring

Kora Core Policies

The [kora] section configures core server behavior:

[kora]
rate_limit = 100
payment_address = "YourPaymentAddressPubkey11111111111111111111"  # Optional

Option	Description	Required	Type
`rate_limit`	Global rate limit (requests per second) across all clients	✅	number
`payment_address`	Optional payment address to receive payment tokens (defaults to signer address(es) if not specified)	❌	b58-encoded string

Kora Authentication

The [kora.auth] section configures authentication for the Kora server:

[kora.auth]
api_key = "kora_live_sk_1234567890abcdef"
hmac_secret = "kora_hmac_your-strong-hmac-secret-key-here"
max_timestamp_age = 300

Option	Description	Required	Type
`api_key`	API key for simple authentication	❌	string
`hmac_secret`	HMAC secret for signature-based authentication (min 32 chars)	❌	string
`max_timestamp_age`	Maximum age of an HMAC timestamp in seconds	❌ (default: 300)	number

Note: api_key and hmac_secret set a global authentication policy for all clients. For detailed authentication setup, see Authentication Guide.

Kora Caching (optional)

The [kora.cache] section configures Redis-based caching for Solana RPC calls. This can significantly improve performance by reducing redundant account data fetches:

[kora.cache]
enabled = true                      # Enable/disable caching
url = "redis://localhost:6379"      # Redis connection URL
default_ttl = 300                   # Default TTL in seconds (5 minutes)
account_ttl = 60                    # Account data TTL in seconds (1 minute)

Option	Description	Required	Type
`enabled`	Enable Redis caching for RPC calls	❌ (default: false)	boolean
`url`	Redis connection URL (required when enabled)	✅	string
`default_ttl`	Default TTL for cached entries in seconds	❌ (default: 300)	number
`account_ttl`	TTL for account data cache in seconds	❌ (default: 60)	number

Note: When caching is enabled, a Redis instance must be available at the specified URL. The cache gracefully falls back to direct RPC calls if Redis is unavailable.

Kora Usage Limits (optional)

The [kora.usage_limit] section configures per-wallet transaction limiting to prevent abuse and ensure fair usage across your users. This could also be used to create rewards programs to subsidize users' transaction fees up to a certain limit.

Important: Currently, the only form of usage limiting supported by Kora is a permanent limit. Once a wallet reaches its transaction limit, it cannot be reset and the user will no longer be able to submit any more transactions using that same wallet. This limit persists until manually cleared from Redis or the Redis data is reset.

Note: This feature requires Redis when enabled across multiple Kora instances:

[kora.usage_limit]
enabled = true                      # Enable/disable usage limiting
cache_url = "redis://localhost:6379" # Redis URL for shared state (required when enabled)
max_transactions = 100              # Max transactions per wallet (0 = unlimited)
fallback_if_unavailable = true      # Continue if Redis is unavailable

Option	Description	Required	Type
`enabled`	Enable per-wallet transaction limiting	❌ (default: false)	boolean
`cache_url`	Redis connection URL for shared usage tracking	❌	string
`max_transactions`	Maximum transactions per wallet (0 = unlimited)	❌ (default: 100)	number
`fallback_if_unavailable`	Allow transactions if Redis is unavailable	❌ (default: true)	boolean

Note: Usage limits are tracked per wallet address with automatic TTL-based expiration. When fallback_if_unavailable is true, the system allows transactions to proceed if Redis is temporarily unavailable, preventing service disruption. Setting max_transactions to 0 will allow unlimited transactions.

Kora Enabled Methods (optional)

The [kora.enabled_methods] section controls which RPC methods are enabled. This section is optional and by default, all methods are enabled. Each method can be enabled or disabled by setting the value to true or false:

[kora.enabled_methods]
liveness = true
estimate_transaction_fee = true
get_supported_tokens = true
sign_transaction = false
sign_and_send_transaction = false
transfer_transaction = false
get_blockhash = true
get_config = true
get_payer_signer = true

Option	Method Description	Required	Type
`liveness`	Health check endpoint	✅	boolean
`estimate_transaction_fee`	Estimate the fee for a transaction	✅	boolean
`get_supported_tokens`	List accepted tokens	✅	boolean
`sign_transaction`	Sign a transaction without sending it to the network	✅	boolean
`sign_and_send_transaction`	Sign a transaction and send it to the network	✅	boolean
`transfer_transaction`	Handle token transfers	✅	boolean
`get_blockhash`	Get a recent blockhash	✅	boolean
`get_config`	Return the Kora server config	✅	boolean

Note: if this section is included in your kora.toml file, all methods must explicitly be set to true or false.

Validation Policies

The [validation] section defines Solana-related security rules and transaction limits:

[validation]
max_allowed_lamports = 1000000  # 0.001 SOL
max_signatures = 10
price_source = "Jupiter"
allowed_programs = [
    "11111111111111111111111111111111",              # System Program (required for SOL transfers)
    "TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA",   # SPL Token Program
    "TokenzQdBNbLqP5VEhdkAS6EPFLC1PHnBqCXEpPxuEb",   # Token-2022 Program
    "ATokenGPvbdGVxr1b2hvZbsiqW5xWH25efTNsLJA8knL",  # Associated Token Program
    "AddressLookupTab1e1111111111111111111111111",   # Address Lookup Table Program
    "ComputeBudget11111111111111111111111111111111", # Compute Budget Program
]
allowed_tokens = [
    "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",  # USDC (mainnet)
    # additional tokens here
]
allowed_spl_paid_tokens = [
    "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",  # USDC (mainnet)
    # additional tokens here
]
disallowed_accounts = [
    # "BadActorPubkey11111111111111111111111111111",
]

Option	Description	Required	Type
`max_allowed_lamports`	Setting a maximum number of lamports per transaction limits the Kora node's exposure to a single transaction.	✅	number
`max_signatures`	Solana base fees are a function of the number of signatures in a transaction, so setting a maximum number of signatures per transaction is a good way to prevent users from spending too much SOL on a single transaction.	✅	number
`price_source`	Oracle for token price data	✅	"Jupiter" or "Mock"
`allowed_programs`	Solana programs that transactions can interact with	✅	Array of b58-encoded string
`allowed_tokens`	Token mints that can be used in transactions	✅	Array of b58-encoded string
`allowed_spl_paid_tokens`	SPL tokens accepted as payment for transaction fees	✅	Array of b58-encoded string
`disallowed_accounts`	Accounts that are explicitly blocked from transactions	✅	Array of b58-encoded string

Note: Empty arrays are allowed, but you will need to specify at least one whitelisted allowed_programs, allowed_tokens, allowed_spl_paid_tokens for the Kora node to be able to process transactions. You need to specify the System Program or Token Program for the Kora node to be able to process transfers. To enable common instruction types (e.g., Compute Budget, Address Lookup Table), you need to specify the Compute Budget Program or Address Lookup Table Program, etc.

Token-2022 Extension Blocking

The [validation.token2022] section allows you to block specific Token-2022 extensions for enhanced security. All extensions are enabled by default. You can block specific extensions by adding them to the blocked_mint_extensions or blocked_account_extensions arrays:

[validation.token2022]
blocked_mint_extensions = [
    "transfer_hook",           # Block tokens with transfer hooks
    "pausable",                # Block pausable tokens
    "permanent_delegate",      # Block tokens with permanent delegates
]
blocked_account_extensions = [
    "cpi_guard",              # Block accounts with CPI guard
    "memo_transfer",          # Block accounts requiring memos
]

Available Mint Extensions

Extension Name	Description
`confidential_transfer_mint`	Confidential transfer configuration for the mint
`confidential_mint_burn`	Confidential mint and burn configuration
`transfer_fee_config`	Transfer fee configuration
`mint_close_authority`	Authority allowed to close the mint
`interest_bearing_config`	Interest-bearing token configuration
`non_transferable`	Makes tokens non-transferable
`permanent_delegate`	Permanent delegate for the mint
`transfer_hook`	Custom transfer hook program
`pausable`	Pausable token configuration

Available Account Extensions

Extension Name	Description
`confidential_transfer_account`	Confidential transfer state for the account
`non_transferable_account`	Non-transferable token account
`transfer_hook_account`	Transfer hook state for the account
`pausable_account`	Pausable token account state
`memo_transfer`	Requires memo for transfers
`cpi_guard`	Prevents certain CPI calls
`immutable_owner`	Account owner cannot be changed
`default_account_state`	Default state for new accounts

Note: Blocking extensions helps prevent interactions with tokens that have complex or potentially risky behaviors. For example, blocking transfer_hook prevents signing transactions for tokens with custom transfer logic.

Security Considerations

PermanentDelegate Extension - Tokens with this extension allow the delegate to transfer/burn tokens at any time without owner approval. This creates significant risks for the Kora node operator as payment funds can be seized after payment.

Consider adding "permanent_delegate" to blocked_mint_extensions in [validation.token2022] unless explicitly needed for your use case.
Avoid using payment tokens with the permanent_delegate extension.

Fee Payer Policy

The [validation.fee_payer_policy] section provides granular control over what actions your Kora node's fee payer wallet can perform. The policy is organized by program type (System, SPL Token, Token-2022) and covers all different instruction types. This prevents unexpected behavior from users' transactions utilizing your Kora node as a signer.

For example, if spl_token.allow_transfer is set to false, the Kora node will not sign transactions that include an SPL token transfer where the Kora node's fee payer is the transfer authority.

[validation.fee_payer_policy.system]
allow_transfer = false           # System Transfer/TransferWithSeed
allow_assign = false             # System Assign/AssignWithSeed
allow_create_account = false     # System CreateAccount/CreateAccountWithSeed
allow_allocate = false           # System Allocate/AllocateWithSeed

[validation.fee_payer_policy.system.nonce]
allow_initialize = false         # InitializeNonceAccount
allow_advance = false            # AdvanceNonceAccount
allow_authorize = false          # AuthorizeNonceAccount
allow_withdraw = false           # WithdrawNonceAccount

[validation.fee_payer_policy.spl_token]
allow_transfer = false           # Transfer/TransferChecked
allow_burn = false               # Burn/BurnChecked
allow_close_account = false      # CloseAccount
allow_approve = false            # Approve/ApproveChecked
allow_revoke = false             # Revoke
allow_set_authority = false      # SetAuthority
allow_mint_to = false            # MintTo/MintToChecked
allow_initialize_mint = false    # InitializeMint/InitializeMint2
allow_initialize_account = false # InitializeAccount/InitializeAccount3
allow_initialize_multisig = false # InitializeMultisig/InitializeMultisig2
allow_freeze_account = false     # FreezeAccount
allow_thaw_account = false       # ThawAccount

[validation.fee_payer_policy.token_2022]
allow_transfer = false           # Transfer/TransferChecked
allow_burn = false               # Burn/BurnChecked
allow_close_account = false      # CloseAccount
allow_approve = false            # Approve/ApproveChecked
allow_revoke = false             # Revoke
allow_set_authority = false      # SetAuthority
allow_mint_to = false            # MintTo/MintToChecked
allow_initialize_mint = false    # InitializeMint/InitializeMint2
allow_initialize_account = false # InitializeAccount/InitializeAccount3
allow_initialize_multisig = false # InitializeMultisig/InitializeMultisig2
allow_freeze_account = false     # FreezeAccount
allow_thaw_account = false       # ThawAccount

System Program Instructions

Option	Description	Default	Type
`allow_transfer`	Allow fee payer as sender in Transfer/TransferWithSeed instructions	`false`	boolean
`allow_assign`	Allow fee payer as authority in Assign/AssignWithSeed instructions	`false`	boolean
`allow_create_account`	Allow fee payer as funding payer in CreateAccount/CreateAccountWithSeed instructions	`false`	boolean
`allow_allocate`	Allow fee payer as account owner in Allocate/AllocateWithSeed instructions	`false`	boolean
`nonce.allow_initialize`	Allow fee payer to be set as nonce authority in InitializeNonceAccount	`false`	boolean
`nonce.allow_advance`	Allow fee payer as authority in AdvanceNonceAccount	`false`	boolean
`nonce.allow_authorize`	Allow fee payer as current authority in AuthorizeNonceAccount	`false`	boolean
`nonce.allow_withdraw`	Allow fee payer as authority in WithdrawNonceAccount	`false`	boolean

SPL Token Program Instructions

Option	Description	Default	Type
`allow_transfer`	Allow fee payer as owner in Transfer/TransferChecked instructions	`false`	boolean
`allow_burn`	Allow fee payer as owner in Burn/BurnChecked instructions	`false`	boolean
`allow_close_account`	Allow fee payer as owner in CloseAccount instructions	`false`	boolean
`allow_approve`	Allow fee payer as owner in Approve/ApproveChecked instructions	`false`	boolean
`allow_revoke`	Allow fee payer as owner in Revoke instructions	`false`	boolean
`allow_set_authority`	Allow fee payer as current authority in SetAuthority instructions	`false`	boolean
`allow_mint_to`	Allow fee payer as mint authority in MintTo/MintToChecked instructions	`false`	boolean
`allow_initialize_mint`	Allow fee payer as mint authority in InitializeMint/InitializeMint2 instructions	`false`	boolean
`allow_initialize_account`	Allow fee payer as owner in InitializeAccount/InitializeAccount3 instructions	`false`	boolean
`allow_initialize_multisig`	Allow fee payer as signer in InitializeMultisig/InitializeMultisig2 instructions	`false`	boolean
`allow_freeze_account`	Allow fee payer as freeze authority in FreezeAccount instructions	`false`	boolean
`allow_thaw_account`	Allow fee payer as freeze authority in ThawAccount instructions	`false`	boolean

Token-2022 supports the same instruction set as SPL Token with identical configuration options (under the [validation.fee_payer_policy.token_2022] section).

Security Considerations

SECURITY WARNING: For security reasons, it is recommended to set all of these to false (default) and only enable as needed. This will prevent unwanted behavior such as users draining your fee payer account or burning tokens from your fee payer account. This prevents:

Account Drainage: Users transferring SOL or tokens from your fee payer account
Authority Takeover: Users changing authorities on accounts owned by your fee payer
Unauthorized Minting: Users minting tokens if your fee payer has mint authority
Account Manipulation: Users freezing, closing, or modifying accounts controlled by your fee payer

Best Practice: Start with all permissions disabled and enable only the minimum set needed for your specific use case.

Price Configuration (optional)

The [validation.price] section defines how transaction fees are calculated. Three pricing models are available:

Margin Pricing (default) - Add a percentage margin on top of actual network fees (default margin is 0.0)
Fixed Pricing - Charge a fixed amount in a specific token regardless of network fees
Free Pricing - Sponsor all transaction fees (no charge to users)

Option	Description	Required	Type
`type`	Pricing model to use	✅	"margin", "fixed" or "free"
`margin`	Margin percentage to add to network fees	(when `type` is "margin")	number
`amount`	Fixed amount to charge in token's base units	(when `type` is "fixed")	number
`token`	Token mint to charge in	(when `type` is "fixed")	b58-encoded string

Margin Pricing

Add a percentage margin on top of actual network fees:

[validation.price]
type = "margin"
margin = 0.1  # 10% margin (0.1 = 10%, 1.0 = 100%)

Fixed Pricing

SECURITY WARNING: Fixed pricing does NOT include fee payer outflow in the charged amount. This can allow users to drain your fee payer account if not properly configured.

Charge a fixed amount in a specific token regardless of network fees:

[validation.price]
type = "fixed"
amount = 1000000  # Amount in token's base units
token = "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v"  # USDC mint

Free Transactions

Sponsor all transaction fees (no charge to users):

[validation.price]
type = "free"

Security Measures When Using Fixed/Free Pricing

Disable All Transfer and Monetary Operations - Prevent fee payer from being used as source in transfers:

[validation.fee_payer_policy.system]
allow_transfer = false              # Block SOL transfers
allow_create_account = false        # Block account creation with lamports
allow_allocate = false              # Block space allocation

[validation.fee_payer_policy.system.nonce]
allow_withdraw = false              # Block nonce account withdrawals

[validation.fee_payer_policy.spl_token] # and for [validation.fee_payer_policy.token_2022]
allow_transfer = false              # Block SPL transfers
allow_burn = false                  # Block SPL token burning
allow_close_account = false         # Block SPL token account closures (returns rent)
allow_mint_to = false               # Block unauthorized SPL token minting
allow_initialize_account = false    # Block account initialization

Enable Authentication - Use authentication to prevent abuse:

[kora.auth]
api_key = "your-secure-api-key"
# or
hmac_secret = "your-minimum-32-character-hmac-secret"

Set Conservative Limits - Minimize exposure:

[validation]
max_allowed_lamports = 1000000  # 0.001 SOL maximum

WARNING: Particularly dangerous operations when using fixed/free pricing:

allow_mint_to: Could allow unlimited token creation if fee payer has mint authority

allow_set_authority: Could transfer control of critical accounts to attackers

allow_transfer: Enables direct drainage of fee payer token balances

allow_close_account: Returns rent to attacker-controlled accounts

Performance Monitoring (optional)

The [metrics] section configures metrics collection and monitoring. This section is optional and by default, metrics are disabled.

[metrics]
enabled = true
endpoint = "/metrics"
port = 8080
scrape_interval = 60

[metrics.fee_payer_balance]
enabled = true
expiry_seconds = 30

Option	Description	Required	Type
`enabled`	Enable metrics collection	✅	boolean
`endpoint`	Custom metrics endpoint path	✅	string
`port`	Metrics endpoint port	✅	number
`scrape_interval`	Frequency of Prometheus scrape (seconds)	✅	number

Fee Payer Balance Tracking

The [metrics.fee_payer_balance] section configures automatic monitoring of your fee payer's SOL balance:

Option	Description	Required	Type
`enabled`	Enable fee payer balance tracking	❌ (default: false)	boolean
`expiry_seconds`	Background tracking interval in seconds	❌ (default: 30)	number

When enabled, Kora automatically tracks your fee payer's SOL balance and exposes it via the fee_payer_balance_lamports Prometheus gauge. This helps with capacity planning and low-balance alerting.

Note: Metrics are served at http://localhost:{port}/{metrics-endpoint} (Metrics can be served on the same port as the RPC server).

→ Kora Monitoring Reference Guide

Complete Example

Here's a production-ready configuration with security best practices:

# Kora Paymaster Configuration
# Last Updated: 2025-08-22

[kora]
# Rate limiting: 100 requests per second globally
rate_limit = 100

# Optional payment address (defaults to signer address(es) if not specified)
# payment_address = "YourPaymentAddressPubkey11111111111111111111"

[kora.auth]
# Authentication (choose based on security needs)
# api_key = "kora_live_sk_generate_secure_key_here"
hmac_secret = "kora_hmac_minimum_32_character_secret_here"
max_timestamp_age = 300

# Caching configuration (optional but recommended for production)
[kora.cache]
enabled = true
url = "redis://localhost:6379"
default_ttl = 300  # 5 minutes
account_ttl = 60   # 1 minute

# Usage limiting (optional, prevents abuse)
[kora.usage_limit]
enabled = true
cache_url = "redis://localhost:6379"  # Can share same Redis instance as cache
max_transactions = 100                # Per-wallet limit
fallback_if_unavailable = true        # Don't block if Redis is down

# Disable unnecessary RPC methods for security
[kora.enabled_methods]
liveness = true
estimate_transaction_fee = true
get_supported_tokens = true
sign_transaction = false
sign_and_send_transaction = false
transfer_transaction = false
get_blockhash = true
get_config = true
get_payer_signer = true

[validation]
# Use production oracle
price_source = "Jupiter"

# Conservative transaction limits
max_allowed_lamports = 1000000  # 0.001 SOL max
max_signatures = 10

# Minimal program allowlist (expand as needed)
allowed_programs = [
    "11111111111111111111111111111111",              # System Program
    "TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA",   # SPL Token
    "ATokenGPvbdGVxr1b2hvZbsiqW5xWH25efTNsLJA8knL",  # Associated Token
    "AddressLookupTab1e1111111111111111111111111",   # Address Lookup Table
    "ComputeBudget11111111111111111111111111111111", # Compute Budget
    "MyProgram111111111111111111111111111111111", 
    # Add your specific program IDs here
]

# Production token allowlist
allowed_tokens = [
    "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",  # USDC
    "So11111111111111111111111111111111111111112",   # Wrapped SOL
    "MyToken1111111111111111111111111111111111111111",
    # Add tokens your application uses
]

# Payment tokens (only liquid, trusted tokens)
allowed_spl_paid_tokens = [
    "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",  # USDC only
]

# Known bad actors or compromised addresses
disallowed_accounts = [
    "BadActor1111111111111111111111111111111111111111",
]

# Restrictive fee payer policy (recommended for production)
[validation.fee_payer_policy.system]
allow_transfer = false           # Block SOL transfers from fee payer
allow_assign = false             # Block account ownership changes
allow_create_account = false     # Block creating accounts with fee payer funds
allow_allocate = false           # Block allocating space for fee payer accounts

[validation.fee_payer_policy.system.nonce]
allow_initialize = false         # Block nonce account initialization
allow_advance = false            # Block nonce advancement
allow_authorize = false          # Block nonce authority changes
allow_withdraw = false           # Block nonce withdrawals

[validation.fee_payer_policy.spl_token]
allow_transfer = false           # Critical: Block SPL transfers
allow_burn = false               # Block token burning
allow_close_account = false      # Block account closures
allow_approve = false            # Block token approvals
allow_revoke = false             # Block delegate revocations
allow_set_authority = false      # Block authority changes
allow_mint_to = false            # Block minting operations
allow_initialize_mint = false    # Block mint initialization
allow_initialize_account = false # Block account initialization
allow_initialize_multisig = false # Block multisig initialization
allow_freeze_account = false     # Block account freezing
allow_thaw_account = false       # Block account thawing

[validation.fee_payer_policy.token_2022]
allow_transfer = false           # Critical: Block Token2022 transfers
allow_burn = false               # Block token burning
allow_close_account = false      # Block account closures
allow_approve = false            # Block token approvals
allow_revoke = false             # Block delegate revocations
allow_set_authority = false      # Block authority changes
allow_mint_to = false            # Block minting operations
allow_initialize_mint = false    # Block mint initialization
allow_initialize_account = false # Block account initialization
allow_initialize_multisig = false # Block multisig initialization
allow_freeze_account = false     # Block account freezing
allow_thaw_account = false       # Block account thawing

# Token-2022 extension blocking
[validation.token2022]
# Block potentially risky mint extensions
blocked_mint_extensions = [
    "transfer_hook",       # Custom transfer logic
    "pausable",            # Can freeze transfers
    "permanent_delegate",  # Permanent control
]
# Block complex account extensions
blocked_account_extensions = [
    "cpi_guard",      # Restricts composability
    "memo_transfer",  # Requires additional data
]

# Sustainable pricing with 15% margin
[validation.price]
type = "margin"
margin = 0.15  # 15% margin on network fees

# Metrics collection
[metrics]
enabled = true
endpoint = "/metrics"
port = 8080
scrape_interval = 60

# Fee payer balance monitoring
[metrics.fee_payer_balance]
enabled = true
expiry_seconds = 30

Configuration Validation

Kora validates your configuration on startup. If you would like to validate your configuration without starting the server, you can use the config validation command:

kora --config kora.toml config validate # or validate-with-rpc

You can also run the validate-with-rpc command to validate your configuration with the RPC server (this validation check is a little bit slower but does more thorough account checks)

Starting the Server

Once you have configured your kora.toml file, you can start the Kora server:

kora --config path/to/kora.toml rpc start --no-load-signer # --other-rpc-flags-here

The --no-load-signer flag will initialize the server without loading any signers. This is useful for testing your configuration. In order to load signers, you will need to configure the signers.toml file. A minimum configuration with a single signer would look like this:

[signer_pool]
# Selection strategy: round_robin, random, weighted
strategy = "round_robin"

# Primary memory signer
[[signers]]
name = "my-signer"
type = "memory"
private_key_env = "MY_SIGNER_PRIVATE_KEY"

This will load a single signer from the MY_SIGNER_PRIVATE_KEY environment variable. Then you can start your server with:

kora --config path/to/kora.toml rpc start --signers-config path/to/signers.toml

For more information and advanced signer configuration, see the Signers Guide.

Best Practices

Start Restrictive: Begin with tight limits and gradually expand
Monitor Usage: Track which programs and tokens are actually used
Regular Updates: Review and update blocklists and limits
Test Changes: Validate configuration changes in staging first
Versioning: Keep a changelog of your configuration changes

Need Help?

Check Authentication Guide for auth setup
Check Signers Guide for signer configuration
Check Operator Guide for more information on how to run a Kora node
Visit Solana Stack Exchange with the kora tag
Report issues on GitHub