diff --git a/src/crawler.rs b/src/crawler.rs
index 20b63f4..3679d22 100644
--- a/src/crawler.rs
+++ b/src/crawler.rs
@@ -12,7 +12,7 @@ use url::Url;
 
 use crate::{
     config::CrawlerConfig,
-    serde_types::{Instance, LoadedData, Service},
+    serde_types::{HttpCodeRanges, Instance, LoadedData, Service},
 };
 
 fn default_headers() -> reqwest::header::HeaderMap {
@@ -172,27 +172,7 @@ impl Crawler {
             Ok(response) => {
                 let end = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
                 let status_code = response.status().as_u16();
-                let mut status_valid = false;
-                match status_code {
-                    200 => status_valid = true,
-                    300..=399 => {
-                        if service.allow_3xx {
-                            status_valid = true;
-                        }
-                    }
-                    400..=499 => {
-                        if service.allow_4xx {
-                            status_valid = true;
-                        }
-                    }
-                    500..=599 => {
-                        if service.allow_5xx {
-                            status_valid = true;
-                        }
-                    }
-                    _ => {}
-                }
-                if status_valid {
+                if service.allowed_http_codes.is_allowed(status_code) {
                     if let Some(search_string) = &service.search_string {
                         let body = response.text().await?;
                         if !body.contains(search_string) {
diff --git a/src/serde_types.rs b/src/serde_types.rs
index dfd2700..24bbf0a 100644
--- a/src/serde_types.rs
+++ b/src/serde_types.rs
@@ -1,6 +1,9 @@
-use std::collections::HashMap;
+use std::{collections::HashMap, fmt, vec};
 
-use serde::{Deserialize, Serialize};
+use serde::{
+    de::{self, Visitor},
+    Deserialize, Deserializer, Serialize, Serializer,
+};
 use url::Url;
 
 #[derive(Deserialize, Serialize, Debug, Clone)]
@@ -30,6 +33,126 @@ pub struct RegexSearch {
 
 pub type Regexes = HashMap<String, Vec<CompiledRegexSearch>>;
 
+pub trait HttpCodeRanges {
+    fn is_allowed(&self, code: u16) -> bool;
+}
+
+#[derive(Debug, Clone)]
+pub struct AllowedHttpCodes {
+    pub codes: Vec<u16>,
+    pub inclusive_ranges: Vec<(u16, u16)>,
+    pub exclusive_ranges: Vec<(u16, u16)>,
+}
+
+impl HttpCodeRanges for AllowedHttpCodes {
+    fn is_allowed(&self, code: u16) -> bool {
+        if self.codes.contains(&code) {
+            return true;
+        }
+
+        for &(start, end) in &self.inclusive_ranges {
+            if code >= start && code <= end {
+                return true;
+            }
+        }
+
+        for &(start, end) in &self.exclusive_ranges {
+            if code >= start && code < end {
+                return true;
+            }
+        }
+
+        false
+    }
+}
+
+impl<'de> Deserialize<'de> for AllowedHttpCodes {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct AllowedHttpCodesVisitor;
+
+        impl<'de> Visitor<'de> for AllowedHttpCodesVisitor {
+            type Value = AllowedHttpCodes;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("a string representing allowed HTTP codes and ranges")
+            }
+
+            fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+            where
+                E: de::Error,
+            {
+                let mut codes = Vec::new();
+                let mut inclusive_ranges = Vec::new();
+                let mut exclusive_ranges = Vec::new();
+
+                for part in value.split(',') {
+                    if part.contains("..=") {
+                        let mut split = part.split("..=");
+                        let start = split.next().unwrap().trim();
+                        let end = split.next().unwrap().trim();
+                        let start = start.parse::<u16>().map_err(de::Error::custom)?;
+                        let end = end.parse::<u16>().map_err(de::Error::custom)?;
+                        inclusive_ranges.push((start, end));
+                    } else if part.contains("..") {
+                        let mut split = part.split("..");
+                        let start = split.next().unwrap().trim();
+                        let end = split.next().unwrap().trim();
+                        let start = start.parse::<u16>().map_err(de::Error::custom)?;
+                        let end = end.parse::<u16>().map_err(de::Error::custom)?;
+                        exclusive_ranges.push((start, end));
+                    } else {
+                        let code = part.trim().parse::<u16>().map_err(de::Error::custom)?;
+                        codes.push(code);
+                    }
+                }
+
+                Ok(AllowedHttpCodes {
+                    codes,
+                    inclusive_ranges,
+                    exclusive_ranges,
+                })
+            }
+        }
+
+        deserializer.deserialize_str(AllowedHttpCodesVisitor)
+    }
+}
+
+impl Serialize for AllowedHttpCodes {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut parts = Vec::new();
+
+        for &code in &self.codes {
+            parts.push(code.to_string());
+        }
+
+        for &(start, end) in &self.inclusive_ranges {
+            parts.push(format!("{}..={}", start, end));
+        }
+
+        for &(start, end) in &self.exclusive_ranges {
+            parts.push(format!("{}..{}", start, end));
+        }
+
+        let result = parts.join(",");
+        serializer.serialize_str(&result)
+    }
+}
+
+fn default_allowed_http_codes() -> AllowedHttpCodes {
+    AllowedHttpCodes {
+        codes: vec![200],
+        inclusive_ranges: Vec::new(),
+        exclusive_ranges: Vec::new(),
+    }
+}
+
 #[derive(Deserialize, Serialize, Debug, Clone)]
 pub struct Service {
     #[serde(rename = "type")]
@@ -39,12 +162,8 @@ pub struct Service {
     pub fallback: Url,
     #[serde(default = "default_follow_redirects")]
     pub follow_redirects: bool,
-    #[serde(default)]
-    pub allow_3xx: bool,
-    #[serde(default)]
-    pub allow_4xx: bool,
-    #[serde(default)]
-    pub allow_5xx: bool,
+    #[serde(default = "default_allowed_http_codes")]
+    pub allowed_http_codes: AllowedHttpCodes,
     #[serde(default)]
     pub search_string: Option<String>,
     #[serde(default)]