diff --git a/CHANGELOG.md b/CHANGELOG.md
index 947a8f9..f81e4d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,15 @@
 # Changelog
 
+## [Unreleased]
+
+### Added
+
+- Internal `Innmind\HttpTransport\Config::asAsync()`
+
+### Deprecated
+
+- `Innmind\HttpTransport\Transport::async()`
+
 ## 9.2.0 - 2026-08-16
 
 ### Changed
diff --git a/src/Config.php b/src/Config.php
index 2b3b4c0..17bf9db 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -3,7 +3,13 @@
 
 namespace Innmind\HttpTransport;
 
+use Innmind\HttpTransport\Config\Async;
+use Innmind\IO\IO;
 use Innmind\Url\Url;
+use Innmind\Time\{
+    Clock,
+    Halt,
+};
 use Innmind\Immutable\Maybe;
 
 /**
@@ -14,11 +20,13 @@ final class Config
     /**
      * @param Maybe<int<1, max>> $maxConcurrency
      * @param Maybe<Url> $proxy
+     * @param Maybe<Async> $async,
      */
     private function __construct(
         private Maybe $maxConcurrency,
         private bool $verifySSL,
         private Maybe $proxy,
+        private Maybe $async,
     ) {
     }
 
@@ -31,11 +39,14 @@ public static function new(): self
         $maxConcurrency = Maybe::nothing();
         /** @var Maybe<Url> */
         $proxy = Maybe::nothing();
+        /** @var Maybe<Async> */
+        $async = Maybe::nothing();
 
         return new self(
             $maxConcurrency,
             true,
             $proxy,
+            $async,
         );
     }
 
@@ -49,6 +60,7 @@ public function limitConcurrencyTo(int $max): self
             Maybe::just($max),
             $this->verifySSL,
             $this->proxy,
+            $this->async,
         );
     }
 
@@ -63,6 +75,7 @@ public function disableSSLVerification(): self
             $this->maxConcurrency,
             false,
             $this->proxy,
+            $this->async,
         );
     }
 
@@ -73,6 +86,25 @@ public function throughProxy(Url $proxy): self
             $this->maxConcurrency,
             $this->verifySSL,
             Maybe::just($proxy),
+            $this->async,
+        );
+    }
+
+    #[\NoDiscard]
+    public function asAsync(
+        Clock $clock,
+        Halt $halt,
+        IO $io,
+    ): self {
+        return new self(
+            $this->maxConcurrency,
+            $this->verifySSL,
+            $this->proxy,
+            Maybe::just(new Async(
+                $clock,
+                $halt,
+                $io,
+            )),
         );
     }
 
@@ -103,4 +135,14 @@ public function proxy(): Maybe
     {
         return $this->proxy;
     }
+
+    /**
+     * @internal
+     *
+     * @return Maybe<Async>
+     */
+    public function async(): Maybe
+    {
+        return $this->async;
+    }
 }
diff --git a/src/Config/Async.php b/src/Config/Async.php
new file mode 100644
index 0000000..6ca0c92
--- /dev/null
+++ b/src/Config/Async.php
@@ -0,0 +1,37 @@
+<?php
+declare(strict_types = 1);
+
+namespace Innmind\HttpTransport\Config;
+
+use Innmind\IO\IO;
+use Innmind\Time\Clock;
+use Innmind\Time\Halt;
+
+/**
+ * @psalm-immutable
+ * @internal
+ */
+final class Async
+{
+    public function __construct(
+        private Clock $clock,
+        private Halt $halt,
+        private IO $io,
+    ) {
+    }
+
+    public function clock(): Clock
+    {
+        return $this->clock;
+    }
+
+    public function halt(): Halt
+    {
+        return $this->halt;
+    }
+
+    public function io(): IO
+    {
+        return $this->io;
+    }
+}
diff --git a/src/Transport.php b/src/Transport.php
index 055e26b..d59d35d 100644
--- a/src/Transport.php
+++ b/src/Transport.php
@@ -95,6 +95,7 @@ public static function logger(
 
     /**
      * @internal
+     * @deprecated
      *
      * @param callable(): void $heartbeat
      */
diff --git a/src/Transport/CircuitBreaker.php b/src/Transport/CircuitBreaker.php
index c527b1d..be6c4b7 100644
--- a/src/Transport/CircuitBreaker.php
+++ b/src/Transport/CircuitBreaker.php
@@ -4,6 +4,7 @@
 namespace Innmind\HttpTransport\Transport;
 
 use Innmind\HttpTransport\{
+    Config,
     Success,
     ServerError,
     ConnectionFailed,
@@ -78,14 +79,28 @@ public static function of(
     #[\Override]
     public function map(callable $map): self
     {
+        $fulfill = $this->fulfill->map($map);
+
         return new self(
-            $this->fulfill->map($map),
-            $this->clock,
+            $fulfill,
+            $fulfill->config()->async()->match(
+                static fn($async) => $async->clock(),
+                fn() => $this->clock,
+            ),
             $this->delayBeforeRetry,
             Map::of(),
         );
     }
 
+    /**
+     * @psalm-mutation-free
+     */
+    #[\Override]
+    public function config(): Config
+    {
+        return $this->fulfill->config();
+    }
+
     private function open(
         Request $request,
         ServerError|ConnectionFailed $error,
diff --git a/src/Transport/Curl.php b/src/Transport/Curl.php
index 610e72d..db1da72 100644
--- a/src/Transport/Curl.php
+++ b/src/Transport/Curl.php
@@ -114,13 +114,25 @@ public function map(callable $map): self
         return new self(
             $config,
             $this->headerFactory,
-            $this->io,
+            $config->async()->match(
+                static fn($async) => $async->io(),
+                fn() => $this->io,
+            ),
             Concurrency::new($config->maxConcurrency()->match(
                 static fn($max) => $max,
                 static fn() => null,
             )),
-            $this->timeout,
-            $this->heartbeat,
+            $config->async()->match(
+                static fn() => Period::millisecond(10), // this is blocking the active task so it needs to be low
+                fn() => $this->timeout,
+            ),
+            $config
+                ->async()
+                ->map(static fn($async) => $async->halt())
+                ->match(
+                    static fn($halt) => static fn() => $halt(Period::millisecond(1))->unwrap(), // this allows to jump between tasks
+                    fn() => $this->heartbeat,
+                ),
             !$config->verifySSL(),
             $config->proxy()->match(
                 static fn($proxy) => $proxy,
@@ -128,4 +140,13 @@ public function map(callable $map): self
             ),
         );
     }
+
+    /**
+     * @psalm-mutation-free
+     */
+    #[\Override]
+    public function config(): Config
+    {
+        return $this->config;
+    }
 }
diff --git a/src/Transport/ExponentialBackoff.php b/src/Transport/ExponentialBackoff.php
index 33a5162..d962bf3 100644
--- a/src/Transport/ExponentialBackoff.php
+++ b/src/Transport/ExponentialBackoff.php
@@ -4,6 +4,7 @@
 namespace Innmind\HttpTransport\Transport;
 
 use Innmind\HttpTransport\{
+    Config,
     Success,
     Information,
     Redirection,
@@ -80,12 +81,26 @@ public static function of(
     #[\Override]
     public function map(callable $map): self
     {
+        $fulfill = $this->fulfill->map($map);
+
         return self::of(
-            $this->fulfill->map($map),
-            $this->halt,
+            $fulfill,
+            $fulfill->config()->async()->match(
+                static fn($async) => $async->halt(),
+                fn() => $this->halt,
+            ),
         );
     }
 
+    /**
+     * @psalm-mutation-free
+     */
+    #[\Override]
+    public function config(): Config
+    {
+        return $this->fulfill->config();
+    }
+
     /**
      * @param Sequence<Period> $retries
      *
diff --git a/src/Transport/FollowRedirections.php b/src/Transport/FollowRedirections.php
index c628124..0dad84c 100644
--- a/src/Transport/FollowRedirections.php
+++ b/src/Transport/FollowRedirections.php
@@ -4,6 +4,7 @@
 namespace Innmind\HttpTransport\Transport;
 
 use Innmind\HttpTransport\{
+    Config,
     Success,
     Redirection,
 };
@@ -59,6 +60,15 @@ public function map(callable $map): self
         return self::of($this->fulfill->map($map));
     }
 
+    /**
+     * @psalm-mutation-free
+     */
+    #[\Override]
+    public function config(): Config
+    {
+        return $this->fulfill->config();
+    }
+
     /**
      * @param int<0, max> $hops
      *
diff --git a/src/Transport/Implementation.php b/src/Transport/Implementation.php
index bc50615..c07b600 100644
--- a/src/Transport/Implementation.php
+++ b/src/Transport/Implementation.php
@@ -36,4 +36,10 @@ public function __invoke(Request $request): Either;
      */
     #[\NoDiscard]
     public function map(callable $map): self;
+
+    /**
+     * @psalm-mutation-free
+     */
+    #[\NoDiscard]
+    public function config(): Config;
 }
diff --git a/src/Transport/Logger.php b/src/Transport/Logger.php
index 4e0f08b..7b91f11 100644
--- a/src/Transport/Logger.php
+++ b/src/Transport/Logger.php
@@ -4,6 +4,7 @@
 namespace Innmind\HttpTransport\Transport;
 
 use Innmind\HttpTransport\{
+    Config,
     Success,
     Information,
     Redirection,
@@ -62,6 +63,15 @@ public function map(callable $map): self
         );
     }
 
+    /**
+     * @psalm-mutation-free
+     */
+    #[\Override]
+    public function config(): Config
+    {
+        return $this->fulfill->config();
+    }
+
     private function logRequest(Request $request): string
     {
         $this->logger->debug(
diff --git a/src/Transport/Via.php b/src/Transport/Via.php
index ff2372a..2a7670e 100644
--- a/src/Transport/Via.php
+++ b/src/Transport/Via.php
@@ -5,6 +5,7 @@
 
 use Innmind\HttpTransport\Success;
 use Innmind\Http\Request;
+use Innmind\HttpTransport\Config;
 use Innmind\Immutable\Either;
 
 /**
@@ -18,6 +19,7 @@ final class Via implements Implementation
      */
     private function __construct(
         private \Closure $fulfill,
+        private ?Config $config,
     ) {
     }
 
@@ -33,7 +35,7 @@ public function __invoke(Request $request): Either
     public static function of(callable $fulfill): self
     {
         // todo support exposing a Config to the callable ?
-        return new self(\Closure::fromCallable($fulfill));
+        return new self(\Closure::fromCallable($fulfill), null);
     }
 
     /**
@@ -42,6 +44,19 @@ public static function of(callable $fulfill): self
     #[\Override]
     public function map(callable $map): self
     {
-        return $this;
+        /** @psalm-suppress ImpureFunctionCall */
+        return new self(
+            $this->fulfill,
+            $map($this->config()),
+        );
+    }
+
+    /**
+     * @psalm-mutation-free
+     */
+    #[\Override]
+    public function config(): Config
+    {
+        return $this->config ?? Config::new();
     }
 }