diff --git a/src/Request/Enum/Portfolio.php b/src/Request/Enum/Portfolio.php
new file mode 100644
index 0000000..20d67ce
--- /dev/null
+++ b/src/Request/Enum/Portfolio.php
@@ -0,0 +1,10 @@
+<?php
+namespace Inserve\RoutITAPI\Request\Enum;
+
+enum Portfolio: string
+{
+    case Business   = 'Business';
+    case SMB        = 'SMB';
+    case Teleworker = 'Teleworker';
+    case All        = 'All';
+}
\ No newline at end of file
diff --git a/src/Request/Enum/Supplier.php b/src/Request/Enum/Supplier.php
new file mode 100644
index 0000000..43712d6
--- /dev/null
+++ b/src/Request/Enum/Supplier.php
@@ -0,0 +1,13 @@
+<?php
+namespace Inserve\RoutITAPI\Request\Enum;
+
+enum Supplier: string
+{
+    case KPN               = 'KPN';
+    case KPNWEAS           = 'KPNWEAS';
+    case Eurofiber         = 'Eurofiber';
+    case Tele2             = 'Tele2';
+    case Tele2Fiber        = 'Tele2Fiber';
+    case CAIW              = 'CAIW';
+    case OverigeAanbieders = 'OverigeAanbieders';
+}
diff --git a/src/Request/ZipCodeCheckRequest.php b/src/Request/ZipCodeCheckRequest.php
new file mode 100644
index 0000000..c67431f
--- /dev/null
+++ b/src/Request/ZipCodeCheckRequest.php
@@ -0,0 +1,217 @@
+<?php
+
+namespace Inserve\RoutITAPI\Request;
+
+use Inserve\RoutITAPI\Request\Enum\Portfolio;
+use Inserve\RoutITAPI\Request\Enum\Supplier;
+use Symfony\Component\Serializer\Attribute\SerializedName;
+
+/**
+ *
+ */
+final class ZipCodeCheckRequest extends AbstractRoutITRequest
+{
+    protected string $rootNode = 'ZipCodeCheckRequest_V6';
+
+    #[SerializedName('Portfolio')]
+    protected ?string $portfolio = null;
+
+    #[SerializedName('ZipCode')]
+    protected ?string $zipCode = null;
+
+    #[SerializedName('HouseNr')]
+    protected ?int $houseNr = null;
+
+    #[SerializedName('HouseNrExtension')]
+    protected ?string $houseNrExtension = null;
+
+    #[SerializedName('ServiceId')]
+    protected ?string $serviceId = null;
+
+    #[SerializedName('RoomNumber')]
+    protected ?string $roomNumber = null;
+
+    #[SerializedName('IsRoomNumberKnown')]
+    protected ?bool $isRoomNumberKnown = null;
+
+    #[SerializedName('Suppliers')]
+    protected ?array $suppliers = null; // 👈 this will hold ['string' => ['KPN', 'Tele2']]
+
+    /**
+     * @return string|null
+     */
+    public function getPortfolio(): ?string
+    {
+        return $this->portfolio;
+    }
+
+    /**
+     * @param Portfolio|string|null $portfolio
+     */
+    public function setPortfolio(Portfolio|string|null $portfolio): self
+    {
+        if ($portfolio instanceof Portfolio) {
+            $this->portfolio = $portfolio->value;
+        } else {
+            $this->portfolio = $portfolio;
+        }
+
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getZipCode(): ?string
+    {
+        return $this->zipCode;
+    }
+
+    /**
+     * @param string|null $zipCode
+     *
+     * @return $this
+     */
+    public function setZipCode(?string $zipCode): self
+    {
+        $this->zipCode = $zipCode;
+
+        return $this;
+    }
+
+    /**
+     * @return int|null
+     */
+    public function getHouseNr(): ?int
+    {
+        return $this->houseNr;
+    }
+
+    /**
+     * @param int|null $houseNr
+     *
+     * @return $this
+     */
+    public function setHouseNr(?int $houseNr): self
+    {
+        $this->houseNr = $houseNr;
+
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getHouseNrExtension(): ?string
+    {
+        return $this->houseNrExtension;
+    }
+
+    /**
+     * @param string|null $houseNrExtension
+     *
+     * @return $this
+     */
+    public function setHouseNrExtension(?string $houseNrExtension): self
+    {
+        $this->houseNrExtension = $houseNrExtension;
+
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getServiceId(): ?string
+    {
+        return $this->serviceId;
+    }
+
+    /**
+     * @param string|null $serviceId
+     *
+     * @return $this
+     */
+    public function setServiceId(?string $serviceId): self
+    {
+        $this->serviceId = $serviceId;
+
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getRoomNumber(): ?string
+    {
+        return $this->roomNumber;
+    }
+
+    /**
+     * @param string|null $roomNumber
+     *
+     * @return $this
+     */
+    public function setRoomNumber(?string $roomNumber): self
+    {
+        $this->roomNumber = $roomNumber;
+
+        return $this;
+    }
+
+    /**
+     * @return bool|null
+     */
+    public function getIsRoomNumberKnown(): ?bool
+    {
+        return $this->isRoomNumberKnown;
+    }
+
+    /**
+     * @param bool|null $isRoomNumberKnown
+     *
+     * @return $this
+     */
+    public function setIsRoomNumberKnown(?bool $isRoomNumberKnown): self
+    {
+        $this->isRoomNumberKnown = $isRoomNumberKnown;
+
+        return $this;
+    }
+
+    /**
+     * @return array<string, array<string>>|null
+     */
+    public function getSuppliers(): ?array
+    {
+        return $this->suppliers; // ✅ return the nested structure
+    }
+
+    /**
+     * @param array<Supplier|string>|null $suppliers
+     */
+    public function setSuppliers(?array $suppliers): self
+    {
+        if ($suppliers === null) {
+            $this->suppliers = null;
+            return $this;
+        }
+
+        $normalized = [];
+
+        foreach ($suppliers as $supplier) {
+            if ($supplier instanceof Supplier) {
+                $normalized[] = $supplier->value;
+            } elseif ($supplier !== null) {
+                $normalized[] = (string) $supplier;
+            }
+        }
+
+        // This shape matches ArrayOfString → <Suppliers><string>...</string></Suppliers>
+        $this->suppliers = [
+            'string' => $normalized,
+        ];
+
+        return $this;
+    }
+}
diff --git a/src/Response/AvailableSpeed.php b/src/Response/AvailableSpeed.php
new file mode 100644
index 0000000..7f8595d
--- /dev/null
+++ b/src/Response/AvailableSpeed.php
@@ -0,0 +1,285 @@
+<?php
+
+namespace Inserve\RoutITAPI\Response;
+
+use DateTimeImmutable;
+use DateTimeInterface;
+use Inserve\RoutITAPI\Response\Enum\NlsType;
+use Symfony\Component\Serializer\Attribute\SerializedName;
+
+/**
+ *
+ */
+final class AvailableSpeed
+{
+    #[SerializedName('Availability')]
+    protected ?string $availability = null;
+
+    #[SerializedName('Description')]
+    protected ?string $description = null;
+
+    #[SerializedName('NlsType')]
+    protected $nlsType = null;
+
+    #[SerializedName('Remarks')]
+    protected $remarks = null; // note: NO type, just mixed
+
+    #[SerializedName('Technology')]
+    protected ?string $technology = null;
+
+    #[SerializedName('TariffCluster')]
+    protected ?string $tariffCluster = null;
+
+    #[SerializedName('PlanDate')]
+    protected ?DateTimeInterface $planDate = null;
+
+    /**
+     * @return string|null
+     */
+    public function getAvailability(): ?string
+    {
+        return $this->availability;
+    }
+
+    /**
+     * @param string|null $availability
+     *
+     * @return $this
+     */
+    public function setAvailability(?string $availability): self
+    {
+        $this->availability = $availability;
+
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getDescription(): ?string
+    {
+        return $this->description;
+    }
+
+    /**
+     * @param string|null $description
+     *
+     * @return $this
+     */
+    public function setDescription(?string $description): self
+    {
+        $this->description = $description;
+
+        return $this;
+    }
+
+    /**
+     * @return NlsType|null
+     */
+    public function getNlsTypeEnum(): ?NlsType
+    {
+        return NlsType::fromNullable($this->getNlsTypeRaw());
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getNlsTypeRaw(): ?string
+    {
+        return is_string($this->nlsType) && $this->nlsType !== ''
+            ? $this->nlsType
+            : null;
+    }
+
+    /**
+     * @param mixed $value
+     *
+     * @return $this
+     */
+    public function setNlsType(mixed $value): self
+    {
+        // Possible shapes:
+        // - 'Nls6'
+        // - 'Nls1'
+        // - null
+        // - ''
+        // - array with nil metadata (for p6:nil="true")
+        // We only keep it if it's a non-empty string.
+        if (is_string($value) && $value !== '') {
+            $this->nlsType = $value;
+        } else {
+            $this->nlsType = null;
+        }
+
+        return $this;
+    }
+
+    /**
+     * Always return a flat list of non-empty strings.
+     *
+     * @return string[]
+     */
+    public function getRemarks(): array
+    {
+        $raw = $this->remarks;
+
+        if ($raw === null || $raw === '') {
+            return [];
+        }
+
+        // Single scalar → one remark (if non-empty)
+        if (is_scalar($raw) || $raw instanceof \Stringable) {
+            $s = trim((string) $raw);
+            return $s === '' ? [] : [$s];
+        }
+
+        // Traversable → turn into array
+        if ($raw instanceof \Traversable) {
+            $raw = iterator_to_array($raw);
+        }
+
+        // Any array shape → flatten all scalar values
+        if (is_array($raw)) {
+            $out = [];
+
+            $it = new \RecursiveIteratorIterator(
+                new \RecursiveArrayIterator($raw)
+            );
+
+            foreach ($it as $v) {
+                if (is_scalar($v) || $v instanceof \Stringable) {
+                    $s = trim((string) $v);
+                    if ($s !== '') {
+                        $out[] = $s;
+                    }
+                }
+            }
+
+            return $out;
+        }
+
+        // Anything else → no remarks
+        return [];
+    }
+
+    /**
+     * @param mixed $remarks
+     */
+    public function setRemarks(mixed $remarks): self
+    {
+        // Possible shapes:
+        // - null
+        // - ''
+        // - 'some text'
+        // - ['string' => ['Nls6', 'Bestel de ...']]
+        // - ['string' => 'Nls6']
+        // - []
+        $this->remarks = $remarks;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getTechnology(): ?string
+    {
+        return $this->technology;
+    }
+
+    /**
+     * @param string|null $technology
+     *
+     * @return $this
+     */
+    public function setTechnology(?string $technology): self
+    {
+        $this->technology = $technology;
+
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getTariffCluster(): ?string
+    {
+        return $this->tariffCluster;
+    }
+
+    /**
+     * @param string|null $tariffCluster
+     *
+     * @return $this
+     */
+    public function setTariffCluster(?string $tariffCluster): self
+    {
+        $this->tariffCluster = $tariffCluster;
+
+        return $this;
+    }
+
+    /**
+     * @return DateTimeInterface|null
+     */
+    public function getPlanDate(): ?DateTimeInterface
+    {
+        return $this->planDate;
+    }
+
+    /**
+     * @param mixed $planDate
+     *
+     * @return $this
+     */
+    public function setPlanDate(mixed $planDate): self
+    {
+        // Case 1: explicit null or empty string
+        if ($planDate === null || $planDate === '') {
+            $this->planDate = null;
+            return $this;
+        }
+
+        // Case 2: XML decoder gave an array for xsi:nil / attributes
+        if (is_array($planDate)) {
+            $flat = array_change_key_case($planDate, CASE_LOWER);
+
+            // Try to detect any kind of nil="true"
+            $nil =
+                $flat['@xsi:nil'] ??
+                $flat['@nil'] ??
+                $flat['nil'] ??
+                null;
+
+            if ($nil === 'true' || $nil === true || $nil === '1') {
+                $this->planDate = null;
+                return $this;
+            }
+
+            // Unknown array shape → be safe and treat as null
+            $this->planDate = null;
+            return $this;
+        }
+
+        // Case 3: normal date string "2024-02-15T13:45:00"
+        if (is_string($planDate)) {
+            try {
+                $this->planDate = new DateTimeImmutable($planDate);
+            } catch (\Throwable $e) {
+                // Invalid date format → store null, don't kill deserialization
+                $this->planDate = null;
+            }
+
+            return $this;
+        }
+
+        // Case 4: Already a DateTimeInterface (unlikely, but fine)
+        if ($planDate instanceof DateTimeInterface) {
+            $this->planDate = $planDate;
+            return $this;
+        }
+
+        // Fallback: unknown type → null
+        $this->planDate = null;
+        return $this;
+    }
+}
diff --git a/src/Response/AvailableSupplier.php b/src/Response/AvailableSupplier.php
new file mode 100644
index 0000000..02792b0
--- /dev/null
+++ b/src/Response/AvailableSupplier.php
@@ -0,0 +1,105 @@
+<?php
+
+namespace Inserve\RoutITAPI\Response;
+
+use Symfony\Component\Serializer\Attribute\SerializedName;
+use Symfony\Component\Serializer\Attribute\SerializedPath;
+
+/**
+ *
+ */
+final class AvailableSupplier
+{
+    #[SerializedName('Name')]
+    protected ?string $name = null;
+
+    #[SerializedName('ErrorMessage')]
+    protected ?string $errorMessage = null;
+
+    #[SerializedName('LocationInfo')]
+    protected ?string $locationInfo = null;
+
+    /** @var AvailableSpeed[]|null */
+    #[SerializedPath('[AvailableSpeeds][AvailableSpeed_V4]')]
+    protected ?array $availableSpeed = null;
+
+    /**
+     * @return string|null
+     */
+    public function getName(): ?string
+    {
+        return $this->name;
+    }
+
+    /**
+     * @param string|null $name
+     *
+     * @return $this
+     */
+    public function setName(?string $name): self
+    {
+        $this->name = $name;
+
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getErrorMessage(): ?string
+    {
+        return $this->errorMessage;
+    }
+
+    /**
+     * @param string|null $errorMessage
+     *
+     * @return $this
+     */
+    public function setErrorMessage(?string $errorMessage): self
+    {
+        $this->errorMessage = $errorMessage;
+
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getLocationInfo(): ?string
+    {
+        return $this->locationInfo;
+    }
+
+    /**
+     * @param string|null $locationInfo
+     *
+     * @return $this
+     */
+    public function setLocationInfo(?string $locationInfo): self
+    {
+        $this->locationInfo = $locationInfo;
+
+        return $this;
+    }
+
+    /**
+     * @param AvailableSpeed[] $availableSpeed
+     *
+     * @return $this
+     */
+    public function setAvailableSpeed(array $availableSpeed): self
+    {
+        $this->availableSpeed = $availableSpeed;
+
+        return $this;
+    }
+
+    /**
+     * @return AvailableSpeed[]|null
+     */
+    public function getAvailableSpeed(): ?array
+    {
+        return $this->availableSpeed;
+    }
+}
diff --git a/src/Response/Enum/NlsType.php b/src/Response/Enum/NlsType.php
new file mode 100644
index 0000000..c5f9d37
--- /dev/null
+++ b/src/Response/Enum/NlsType.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace Inserve\RoutITAPI\Response\Enum;
+
+enum NlsType: string
+{
+    case Nls1    = 'Nls1';
+    case Nls2    = 'Nls2';
+    case Nls3    = 'Nls3';
+    case Nls4    = 'Nls4';
+    case Nls6    = 'Nls6';
+    case Nls7    = 'Nls7';
+    case Nls8    = 'Nls8';
+    case Nls9    = 'Nls9';
+    case Nls11   = 'Nls11';
+    case Nls21   = 'Nls21';
+    case Nls23   = 'Nls23';
+    case Nls24   = 'Nls24';
+    case NlsIO   = 'NlsIO';
+    case NlsNO   = 'NlsNO';
+    case NlsHbob = 'NlsHbob';
+    case NlsHbor = 'NlsHbor';
+
+    /**
+     * Safely cast a value into the enum, fallback to null
+     */
+    public static function fromNullable(?string $value): ?self
+    {
+        return $value !== null ? self::tryFrom($value) : null;
+    }
+}
\ No newline at end of file
diff --git a/src/Response/ZipCodeCheckResponse.php b/src/Response/ZipCodeCheckResponse.php
new file mode 100644
index 0000000..9bc914b
--- /dev/null
+++ b/src/Response/ZipCodeCheckResponse.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Inserve\RoutITAPI\Response;
+
+use Symfony\Component\Serializer\Attribute\SerializedPath;
+
+/**
+ *
+ */
+final class ZipCodeCheckResponse
+{
+    /** @var AvailableSupplier[]|null */
+    #[SerializedPath('[AvailableSuppliers][AvailableSupplier_V5]')]
+    protected ?array $availableSupplier = null;
+
+    /**
+     * @param AvailableSupplier[] $availableSupplier
+     *
+     * @return $this
+     */
+    public function setAvailableSupplier(array $availableSupplier): self
+    {
+        $this->availableSupplier = $availableSupplier;
+
+        return $this;
+    }
+
+    /**
+     * @return AvailableSupplier[]|null
+     */
+    public function getAvailableSupplier(): ?array
+    {
+        return $this->availableSupplier;
+    }
+}
diff --git a/src/RoutITAPIClient.php b/src/RoutITAPIClient.php
index b5b15aa..fb3e77e 100644
--- a/src/RoutITAPIClient.php
+++ b/src/RoutITAPIClient.php
@@ -9,9 +9,11 @@
 use Inserve\RoutITAPI\Request\OrderSummaryRequest;
 use Inserve\RoutITAPI\Request\ProductPriceDetailsRequest;
 use Inserve\RoutITAPI\Request\RoutITRequestInterface;
+use Inserve\RoutITAPI\Request\ZipCodeCheckRequest;
 use Inserve\RoutITAPI\Response\CustomerDataResponse;
 use Inserve\RoutITAPI\Response\OrderSummaryResponse;
 use Inserve\RoutITAPI\Response\ProductPriceDetailsResponse;
+use Inserve\RoutITAPI\Response\ZipCodeCheckResponse;
 use Psr\Log\LoggerInterface;
 use SensitiveParameter;
 
@@ -89,6 +91,19 @@ public function getProductPriceDetails(): ?ProductPriceDetailsResponse
         /** @var ProductPriceDetailsResponse|null */
         return $this->apiCall(new ProductPriceDetailsRequest(), ProductPriceDetailsResponse::class);
     }
+
+    /**
+     * @param ZipCodeCheckRequest|null $request
+     *
+     * @return ZipCodeCheckResponse|null
+     * @throws RoutITAPIException
+     */
+    public function zipCodeCheck(?ZipCodeCheckRequest $request = null): ?ZipCodeCheckResponse
+    {
+        /** @var ZipCodeCheckResponse|null */
+        return $this->apiCall($request ?? new ZipCodeCheckRequest(), ZipCodeCheckResponse::class);
+    }
+
     /**
      * @param RoutITRequestInterface $request
      * @param string                 $responseClass