diff --git a/src/builder.rs b/src/builder.rs
index d238fe2..8cfa7e7 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -33,7 +33,7 @@ use crate::symbols::wordpress::{
   Plugin as WordpressPluginSymbol, Translation as WordpressTranslationSymbol,
 };
 use crate::templates::nginx;
-use crate::templates::php::fpm_pool_config as php_fpm_pool_config;
+use crate::templates::php::{fpm_pool_config as php_fpm_pool_config, FpmPoolConfig as PhpFpmPoolConfig};
 use crate::templates::systemd::{
   nodejs_service as systemd_nodejs_service, socket_service as systemd_socket_service,
 };
@@ -250,16 +250,16 @@ impl<D: AsRef<str> + Clone + Display> ImplementationBuilder<ServeCustom<D>> for
   }
 }
 
-impl<D: Clone + Display, P: AsRef<Path>> ImplementationBuilder<ServePhp<D, P>> for DefaultBuilder {
+impl<D: Clone + Display, P: AsRef<Path>, C: Clone + Into<PhpFpmPoolConfig>> ImplementationBuilder<ServePhp<D, P, C>> for DefaultBuilder {
   type Prerequisites = (
     PhpFpmPool<D>,
     CertChain<D>,
     Key<D>,
     AcmeChallengesNginxSnippet,
   );
-  fn prerequisites(resource: &ServePhp<D, P>) -> Self::Prerequisites {
+  fn prerequisites(resource: &ServePhp<D, P, C>) -> Self::Prerequisites {
     (
-      PhpFpmPool(resource.0.clone(), 10),
+      PhpFpmPool(resource.0.clone(), resource.4.clone().into()),
       CertChain(resource.0.clone()),
       Key(resource.0.clone()),
       AcmeChallengesNginxSnippet,
@@ -271,8 +271,8 @@ impl<D: Clone + Display, P: AsRef<Path>> ImplementationBuilder<ServePhp<D, P>> f
     ReloadServiceSymbol<StdCommandRunner, StdCommandRunner, &'static str>,
   );
   fn create(
-    resource: &ServePhp<D, P>,
-    target: &<ServePhp<D, P> as Resource>::Artifact,
+    resource: &ServePhp<D, P, C>,
+    target: &<ServePhp<D, P, C> as Resource>::Artifact,
     (pool, cert, key, challenges_snippet_path): <Self::Prerequisites as ToArtifact>::Artifact,
   ) -> Self::Implementation {
     (
@@ -428,7 +428,7 @@ impl<D: Clone> ImplementationBuilder<PhpFpmPool<D>> for DefaultBuilder {
     (
       FileSymbol::new(
         conf_path.clone().into(),
-        php_fpm_pool_config(&user_name.0, &socket_path, resource.1),
+        php_fpm_pool_config(&user_name.0, &socket_path, &resource.1),
       ),
       ReloadServiceSymbol::new(StdCommandRunner, service_name.0.clone()),
     )
diff --git a/src/locator.rs b/src/locator.rs
index 9b70ae4..6633d4e 100644
--- a/src/locator.rs
+++ b/src/locator.rs
@@ -298,11 +298,11 @@ impl<D: AsRef<Path>, POLICY> ResourceLocator<ServeCustom<D>> for DefaultLocator<
   }
 }
 
-impl<D: AsRef<Path>, P, POLICY> ResourceLocator<ServePhp<D, P>> for DefaultLocator<POLICY> {
+impl<D: AsRef<Path>, P, C, POLICY> ResourceLocator<ServePhp<D, P, C>> for DefaultLocator<POLICY> {
   type Prerequisites = ();
   fn locate(
-    resource: &ServePhp<D, P>,
-  ) -> (<ServePhp<D, P> as Resource>::Artifact, Self::Prerequisites) {
+    resource: &ServePhp<D, P, C>,
+  ) -> (<ServePhp<D, P, C> as Resource>::Artifact, Self::Prerequisites) {
     (
       PathArtifact::from(Path::new("/etc/nginx/sites-enabled/").join(&resource.0)),
       (),
diff --git a/src/resources/mod.rs b/src/resources/mod.rs
index 75f6d3e..d8837f5 100644
--- a/src/resources/mod.rs
+++ b/src/resources/mod.rs
@@ -2,6 +2,7 @@ use crate::artifacts::{
   DatabaseName as DatabaseNameArtifact, Path as PathArtifact, ServiceName as ServiceNameArtifact,
   UserName as UserNameArtifact,
 };
+use crate::templates::php::FpmPoolConfig;
 use std::hash::Hash;
 use std::path::PathBuf;
 
@@ -146,8 +147,14 @@ impl<D> Resource for ServeCustom<D> {
 }
 
 #[derive(Debug, Hash, PartialEq, Eq)]
-pub struct ServePhp<D, P>(pub D, pub P, pub &'static str, pub String, pub usize);
-impl<D, P> Resource for ServePhp<D, P> {
+pub struct ServePhp<D, P, C>(
+  pub D,
+  pub P,
+  pub &'static str,
+  pub String,
+  pub C,
+);
+impl<D, P, C> Resource for ServePhp<D, P, C> {
   type Artifact = PathArtifact;
 }
 
@@ -177,7 +184,7 @@ impl Resource for DefaultServer {
 }
 
 #[derive(Debug, Hash, PartialEq, Eq)]
-pub struct PhpFpmPool<D>(pub D, pub usize);
+pub struct PhpFpmPool<D>(pub D, pub FpmPoolConfig);
 impl<D> Resource for PhpFpmPool<D> {
   type Artifact = (
     PathArtifact,
@@ -275,6 +282,7 @@ macro_rules! default_resources {
   }
 }
 
+// Only one enum entry per resource type, otherwise the equality checks fail
 default_resources!(
   AcmeAccountKey: AcmeAccountKey,
   AcmeChallengesDir: AcmeChallengesDir,
@@ -301,7 +309,7 @@ default_resources!(
   PhpFpmPool: PhpFpmPool<D>,
   ServeCustom: ServeCustom<D>,
   ServeService: ServeService<D, PathBuf>,
-  ServePhp: ServePhp<D, PathBuf>,
+  ServePhp: ServePhp<D, PathBuf, FpmPoolConfig>,
   ServeRedir: ServeRedir<D>,
   ServeStatic: ServeStatic<D, PathBuf>,
   StoredDirectory: StoredDirectory<PathBuf>,
@@ -310,3 +318,8 @@ default_resources!(
   WordpressPlugin: WordpressPlugin<PathBuf>,
   WordpressTranslation: WordpressTranslation<PathBuf>,
 );
+
+pub fn serve_php<D, P: Into<PathBuf>, C: Into<FpmPoolConfig>>(domain: D, path: P, root_filename: &'static str, nginx_config: impl Into<String>, pool_config: C) -> ServePhp<D, PathBuf, FpmPoolConfig> {
+  ServePhp(
+    domain, path.into(), root_filename, nginx_config.into(), pool_config.into())
+}
diff --git a/src/templates/php.rs b/src/templates/php.rs
index 87fc6bf..d131fe2 100644
--- a/src/templates/php.rs
+++ b/src/templates/php.rs
@@ -1,9 +1,40 @@
+use std::fmt::{Display, Error, Formatter};
 use std::path::Path;
 
+#[derive(Clone, Debug, PartialEq, Hash, Eq)]
+pub struct FpmPoolConfig {
+  max_children: usize,
+  custom: Option<String>,
+}
+
+impl Display for FpmPoolConfig {
+  fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+    match &self.custom {
+      None => write!(f, "pm.max_children = {}", self.max_children),
+      Some(custom) => write!(f, "pm.max_children = {}\n{}", self.max_children, custom),
+    }
+  }
+}
+
+impl From<usize> for FpmPoolConfig {
+  fn from(max_children: usize) -> Self {
+    Self {
+      max_children,
+      custom: None,
+    }
+  }
+}
+
+impl FpmPoolConfig {
+  pub fn new(max_children: usize, custom: impl Into<String>) -> Self {
+    Self { max_children, custom: Some(custom.into()) }
+  }
+}
+
 pub fn fpm_pool_config<U: AsRef<str>, S: AsRef<Path>>(
   user_name: U,
   socket_path: S,
-  max_children: usize,
+  config: &FpmPoolConfig,
 ) -> String {
   format!(
     "[{0}]
@@ -13,12 +44,12 @@ group = www-data
 listen = {1}
 listen.owner = www-data
 pm = ondemand
-pm.max_children = {2}
 catch_workers_output = yes
 env[PATH] = /usr/local/bin:/usr/bin:/bin
+{2}
 ",
     user_name.as_ref(),
     socket_path.as_ref().to_str().unwrap(),
-    max_children,
+    config
   )
 }