Pattern Matching Reference

Route patterns are pre-compiled at config load time. The pattern type is detected automatically.

Pattern Types

Exact

No special characters. Matches the hostname exactly (case-insensitive).

route "api.example.com" via="proxy"

Domain Suffix

Starts with .. Matches any host ending with the suffix.

route ".example.com" via="proxy"

Input	Matches?
foo.example.com	Yes
bar.baz.example.com	Yes
example.com	No
notexample.com	No

Glob

Contains * or ?. Uses filepath.Match semantics.

route "192.168.*.*" via="proxy"
route "*.cdn.example.com" via="cdn"
route "test?.example.com" via="proxy"

Wildcard	Matches
*	Any sequence of non-separator characters
?	Any single non-separator character

TIP

The separator is . for hostnames and IP addresses. * does not match across dots — 192.* does not match 192.168.1.1. Use 192.*.*.* or a CIDR range instead.

CIDR

Contains / and parses as a valid CIDR network. Matches IP addresses within the range.

route "10.0.0.0/8" via="internal"
route "fd00::/8" via="internal6"

IPv4 and IPv6 are both supported. Non-IP hostnames (e.g. example.com) never match CIDR rules.

Detection Priority

When a pattern could be ambiguous, detection follows this order:

1. Contains / and valid CIDR → CIDR
2. Contains * or ? → Glob
3. Starts with . → Domain suffix
4. Otherwise → Exact

Matching Behavior

• Port stripping — example.com:8080 is matched as example.com
• Case insensitive — patterns and hostnames are lowercased before comparison
• Last match wins — rules are evaluated in order; the last matching rule determines the upstream
• No match — traffic connects directly (no upstream proxy)
• via="direct" — explicitly routes through no proxy, overriding earlier matches

Performance

• Patterns are classified and pre-compiled once at config load
• CIDR networks are parsed into net.IPNet structs — matching is a single Contains call
• Glob patterns use the stdlib filepath.Match function
• Domain suffix and exact matches are simple string operations
• No allocations occur during per-request matching (patterns are lowercased at load time)