# Matcher syntax

> Source: https://docs.erpc.cloud/config/matcher
> Pattern matching DSL used wherever eRPC compares network/method/param/header values — supports wildcards, OR/AND/NOT, and numeric comparisons over hex/decimal.
> Format: machine-readable markdown export of the docs page above.
> All collapsible AI sections are inlined and fully expanded.

# Matcher syntax

Certain configurations accept a matcher syntax with some basic operations designed for blockchain json-rpc request/response values.

Matchers are used in the following configurations:
- [Upstream](/config/projects/upstreams.llms.txt)'s allowMethods or ignoreMethods.
- [Cache policy](/config/database/evm-json-rpc-cache.llms.txt#cache-policies) patterns for network/method/params.
- [Aliasing](/operation/url.llms.txt#domain-aliasing) rules for `Host` header.
- [Failsafe](/config/failsafe.llms.txt) `matchMethod` patterns.

## Examples

```js
// Match one exact method OR any eth_ method
arbtrace_transaction | eth_*

// Match all methods expect those prefixed with alchemy_*
!alchemy_*

// Match a number between 1 and 100
>=1 & <=100

// Match some block tags AND any numeric blocks higher than 1000 (also with hex example)
(latest | safe | finalized) | >=1000
(latest | safe | finalized) | >=0x4096

// Match only numeric values (e.g. ignore block tags)
0x*
```

## Operations

### Wildcards
- `*` - matches any number of characters
- `<empty>` - matches an empty string

### Logical Operations
- `|` - OR operation
- `&` - AND operation
- `!` - NOT operation
- `()` - grouping/nesting operations

### Numeric Comparisons (for hex values)
- `>` - greater than
- `<` - less than
- `>=` - greater than or equal
- `<=` - less than or equal
- `=` - equal to