Policies | 256 Blocks

Control transactions with custom rules using 256 Blocks's Rego-based policy engine

The 256 Blocks policy engine evaluates every request against your defined rules before execution. Policies are written in Rego, a declarative policy language that lets you define what should be blocked rather than how to block it.

Two Rules

Policies control two independent decisions:

Rule	Controls	Default
`deny`	Whether the request is allowed or blocked	`false` (allow)
`denyGasSponsor`	Whether 256 Blocks sponsors the gas fee	`false` (sponsor)

# Block transactions over $10,000
deny if {
    input.usd_value > 10000
}
 
# Don't sponsor transactions over $100
denyGasSponsor if {
    input.usd_value > 100
}

Both rules are evaluated independently. A request can be allowed but not sponsored, or vice versa.

Policy Levels

Policies are evaluated at three levels:

Platform policies - Managed by 256 Blocks, enforce baseline security (e.g., blocked RPC methods)
Organization policies - Apply to all endpoints in your organization
Endpoint policies - Apply to a specific endpoint only

Each level acts as a baseline. If a higher-level policy denies a request, no lower-level policy can allow it.

Common Use Cases

Spending limits - Cap transaction values by USD amount
Geographic restrictions - Block sanctioned countries
Address allowlisting - Only allow specific contracts
Method blocking - Restrict dangerous RPC methods
Time-based rules - Business hours only

Learn More

Introduction - Full policy documentation
Input Fields - Available data for policy decisions
Language Reference - Rego syntax guide
Built-in Functions - Available functions
Restrictions - Security limitations and best practices