diff --git a/lib/ApiClient.php b/lib/ApiClient.php
index 1da793a..0c64da4 100644
--- a/lib/ApiClient.php
+++ b/lib/ApiClient.php
@@ -45,15 +45,18 @@ class ApiClient extends \GuzzleHttp\Client
     private RateLimiter $rateLimiter;
 
     /**
-     * {@inheritDoc}
+     * Initialize the API client with configuration, certificate validation, and a rate limiter.
      *
-     * $config['clientid'] - obtained from Developer Portal - when you registered your app with us.
-     * $config['cert'] = ['/path/to/cert.p12','certificat password']
-     * $config['clientpubip'] = the closest IP address to the real end-user
-     * $config['mocking'] = true to use /rbcz/premium/mock/* endpoints
+     * Accepted $config keys:
+     * - 'clientid': client ID from the Developer Portal.
+     * - 'cert': array with [pathToP12, password]; when omitted, CERT_FILE and CERT_PASS configuration values are used.
+     * - 'clientpubip': client public IP (nearest to the end user).
+     * - 'mocking': bool to enable mock endpoints.
+     * - 'debug': debug flag.
      *
-     * @throws \Exception CERT_FILE is not set
-     * @throws \Exception CERT_PASS is not set
+     * @param array $config Client configuration.
+     * @throws \Exception If certificate file path (CERT_FILE) is not provided.
+     * @throws \Exception If certificate password (CERT_PASS) is not provided.
      */
     public function __construct(array $config = [])
     {
@@ -202,13 +205,11 @@ public static function checkCertificatePassword(string $certFile, string $passwo
     }
 
     /**
-     * Request Identifier.
+     * Produce a short request identifier used for diagnostics and testing.
      *
-     * @todo Obtain using RateLimiter
+     * @deprecated since version 0.1 — Do not use in production environments.
      *
-     * @deprecated since version 0.1 - Do not use in production Environment!
-     *
-     * @return string
+     * @return string The generated request identifier composed from a source token and the current timestamp, truncated to at most 59 characters.
      */
     public static function getxRequestId()
     {
@@ -216,13 +217,13 @@ public static function getxRequestId()
     }
 
     /**
-     * Send an HTTP request.
-     *
-     * @param array $options Request options to apply to the given
-     *                       request and to the transfer. See \GuzzleHttp\RequestOptions.
+     * Send an HTTP request while enforcing and updating client rate limits.
      *
-     * @throws GuzzleException
-     * @throws RateLimitExceededException
+     * @param \Psr\Http\Message\RequestInterface $request The HTTP request to send.
+     * @param array $options Request options to apply to the transfer. See \GuzzleHttp\RequestOptions.
+     * @return \Psr\Http\Message\ResponseInterface The HTTP response.
+     * @throws \GuzzleHttp\Exception\GuzzleException
+     * @throws RateLimitExceededException If the client is rate limited and wait mode is disabled.
      */
     public function send(\Psr\Http\Message\RequestInterface $request, array $options = []): \Psr\Http\Message\ResponseInterface
     {
@@ -253,4 +254,4 @@ public function send(\Psr\Http\Message\RequestInterface $request, array $options
 
         return $response;
     }
-}
+}
\ No newline at end of file
diff --git a/lib/RateLimit/JsonRateLimitStore.php b/lib/RateLimit/JsonRateLimitStore.php
index 51f6231..3ee197b 100644
--- a/lib/RateLimit/JsonRateLimitStore.php
+++ b/lib/RateLimit/JsonRateLimitStore.php
@@ -20,6 +20,13 @@ class JsonRateLimitStore implements RateLimitStoreInterface
     private string $filename;
     private array $data = [];
 
+    /**
+     * Create a JsonRateLimitStore backed by the given file and load any existing data.
+     *
+     * If the file exists, its JSON contents are decoded into the in-memory store; decoding failures result in an empty dataset.
+     *
+     * @param string $filename Path to the JSON file used to persist rate limit data.
+     */
     public function __construct(string $filename)
     {
         $this->filename = $filename;
@@ -30,11 +37,26 @@ public function __construct(string $filename)
         }
     }
 
+    /**
+     * Retrieve the stored rate-limit entry for a client and window.
+     *
+     * @param string $clientId The client identifier.
+     * @param string $window The rate-limit window identifier.
+     * @return array{remaining:int,timestamp:int}|null The entry for the specified client and window: an array with keys `remaining` and `timestamp`, or `null` if not found.
+     */
     public function get(string $clientId, string $window): ?array
     {
         return $this->data[$clientId][$window] ?? null;
     }
 
+    /**
+     * Store the remaining quota and associated timestamp for a client's rate-limit window and persist it to the configured JSON file.
+     *
+     * @param string $clientId Identifier of the client.
+     * @param string $window Identifier of the rate-limit window.
+     * @param int $remaining Number of remaining requests for the specified window.
+     * @param int $timestamp Unix timestamp associated with the stored entry.
+     */
     public function set(string $clientId, string $window, int $remaining, int $timestamp): void
     {
         $this->data[$clientId][$window] = [
@@ -45,13 +67,24 @@ public function set(string $clientId, string $window, int $remaining, int $times
         $this->save();
     }
 
+    /**
+     * Retrieve all rate-limit window entries for a client.
+     *
+     * @param string $clientId The client identifier.
+     * @return array An associative array of windows to entries where each entry contains keys `remaining` (int) and `timestamp` (int); returns an empty array if the client has no entries.
+     */
     public function allForClient(string $clientId): array
     {
         return $this->data[$clientId] ?? [];
     }
 
+    /**
+     * Persist the in-memory rate limit data to the configured JSON file.
+     *
+     * Writes the current $data as pretty-printed JSON into $this->filename.
+     */
     private function save(): void
     {
         file_put_contents($this->filename, json_encode($this->data, \JSON_PRETTY_PRINT));
     }
-}
+}
\ No newline at end of file
diff --git a/lib/RateLimit/PdoRateLimitStore.php b/lib/RateLimit/PdoRateLimitStore.php
index 840c8be..cb01715 100644
--- a/lib/RateLimit/PdoRateLimitStore.php
+++ b/lib/RateLimit/PdoRateLimitStore.php
@@ -19,12 +19,25 @@ class PdoRateLimitStore implements RateLimitStoreInterface
 {
     private \PDO $pdo;
 
+    /**
+     * Store the PDO connection and ensure the rate_limits table exists.
+     *
+     * Initializes the store by saving the provided PDO instance and creating the
+     * `rate_limits` table if it does not already exist.
+     */
     public function __construct(\PDO $pdo)
     {
         $this->pdo = $pdo;
         $this->init();
     }
 
+    /**
+     * Fetches the remaining token count and expiry timestamp for a client's rate-limit window.
+     *
+     * @param string $clientId Identifier of the client.
+     * @param string $window Identifier of the rate-limit window.
+     * @return array{remaining:int, timestamp:int}|null The row for the specified client and window with integer `remaining` and `timestamp`, or `null` if no record exists.
+     */
     public function get(string $clientId, string $window): ?array
     {
         $stmt = $this->pdo->prepare(<<<'EOD'
@@ -40,6 +53,14 @@ public function get(string $clientId, string $window): ?array
         return $row ?: null;
     }
 
+    /**
+     * Store or update the rate-limit record for a client and window.
+     *
+     * @param string $clientId Identifier of the client.
+     * @param string $window Identifier of the rate-limit window (e.g., "1m", "hourly").
+     * @param int $remaining Number of remaining allowed requests for the window.
+     * @param int $timestamp UNIX timestamp associated with the record (seconds since epoch).
+     */
     public function set(string $clientId, string $window, int $remaining, int $timestamp): void
     {
         $stmt = $this->pdo->prepare(<<<'EOD'
@@ -51,6 +72,12 @@ public function set(string $clientId, string $window, int $remaining, int $times
         $stmt->execute([$clientId, $window, $remaining, $timestamp]);
     }
 
+    /**
+     * Fetches all rate-limit entries for a client, indexed by window.
+     *
+     * @param string $clientId The client identifier.
+     * @return array<string, array{remaining:int,timestamp:int}> Associative array keyed by window name; each value contains `remaining` (int) and `timestamp` (int).
+     */
     public function allForClient(string $clientId): array
     {
         $stmt = $this->pdo->prepare(<<<'EOD'
@@ -74,6 +101,12 @@ public function allForClient(string $clientId): array
         return $results;
     }
 
+    /**
+     * Ensure the `rate_limits` table exists in the connected PDO database.
+     *
+     * Creates a table with columns: `client_id` (TEXT), `window` (TEXT), `remaining` (INTEGER),
+     * `timestamp` (INTEGER) and a composite primary key on (`client_id`, `window`).
+     */
     private function init(): void
     {
         $this->pdo->exec(<<<'EOD'
@@ -88,4 +121,4 @@ private function init(): void
 
 EOD);
     }
-}
+}
\ No newline at end of file
diff --git a/lib/RateLimit/RateLimitStore.php b/lib/RateLimit/RateLimitStore.php
index c7d7e1f..c26e068 100644
--- a/lib/RateLimit/RateLimitStore.php
+++ b/lib/RateLimit/RateLimitStore.php
@@ -19,6 +19,13 @@ abstract class RateLimitStore
 {
     protected string $path;
 
+    /**
+     * Initialize the store with the backing file path and ensure the file exists.
+     *
+     * If the file at the provided path does not exist, creates it containing an empty JSON array.
+     *
+     * @param string $path Filesystem path to the JSON file used to persist rate-limit data.
+     */
     public function __construct(string $path)
     {
         $this->path = $path;
@@ -28,9 +35,30 @@ public function __construct(string $path)
         }
     }
 
-    abstract public function get(string $key): array;
-    abstract public function increment(string $key, string $field, int $ttlSeconds): int;
+    /**
+ * Retrieve stored rate-limit entries for the specified key.
+ *
+ * @param string $key The identifier of the rate-limit bucket or resource.
+ * @return array An array of rate-limit records for the key, or an empty array if none exist.
+ */
+abstract public function get(string $key): array;
+    /**
+ * Increment the numeric counter for a rate-limited key and field, applying a time-to-live.
+ *
+ * @param string $key The identifier for the rate-limited entity.
+ * @param string $field The specific counter field to increment.
+ * @param int $ttlSeconds Time to live for the counter in seconds.
+ * @return int The counter value after the increment.
+ */
+abstract public function increment(string $key, string $field, int $ttlSeconds): int;
 
+    /**
+     * Read and decode the JSON contents of the store file.
+     *
+     * Decodes the file contents as an associative array; returns an empty array if the file is empty.
+     *
+     * @return array The decoded data as an associative array, or an empty array when the file has no content.
+     */
     protected function read(): array
     {
         $data = file_get_contents($this->path);
@@ -38,8 +66,15 @@ protected function read(): array
         return $data ? json_decode($data, true) : [];
     }
 
+    /**
+     * Writes the provided data to the storage file as pretty-printed JSON.
+     *
+     * Encodes `$data` to JSON using `JSON_PRETTY_PRINT` and overwrites the file at `$this->path`.
+     *
+     * @param array $data The data to encode and store.
+     */
     protected function write(array $data): void
     {
         file_put_contents($this->path, json_encode($data, \JSON_PRETTY_PRINT));
     }
-}
+}
\ No newline at end of file
diff --git a/lib/RateLimit/RateLimitStoreInterface.php b/lib/RateLimit/RateLimitStoreInterface.php
index e8d236e..9b110e5 100644
--- a/lib/RateLimit/RateLimitStoreInterface.php
+++ b/lib/RateLimit/RateLimitStoreInterface.php
@@ -18,20 +18,32 @@
 interface RateLimitStoreInterface
 {
     /**
-     * Returns stored data for the given client identifier and window (second/day).
-     * Array:
-     *   remaining => int
-     *   timestamp => int (unix time when the value was received).
-     */
+ * Retrieve stored rate-limit data for a client and window.
+ *
+ * @param string $clientId The client identifier.
+ * @param string $window The rate limit window (e.g., "second" or "day").
+ * @return array|null An array with keys `remaining` (int) and `timestamp` (int, Unix time) or `null` if no data is stored.
+ */
     public function get(string $clientId, string $window): ?array;
 
     /**
-     * Stores data for the client and window (second/day).
-     */
+ * Store rate-limit data for a client and time window.
+ *
+ * Stores the number of remaining requests and the associated Unix timestamp for
+ * the specified client identifier and window (e.g., "second" or "day").
+ *
+ * @param string $clientId Identifier of the client.
+ * @param string $window Time window name (for example "second" or "day").
+ * @param int $remaining Number of remaining requests for the client in this window.
+ * @param int $timestamp Unix timestamp representing when the stored data expires or was recorded.
+ */
     public function set(string $clientId, string $window, int $remaining, int $timestamp): void;
 
     /**
-     * Returns all data for one client (for debugging).
-     */
+ * Retrieve stored rate-limit data for the given client (intended for debugging).
+ *
+ * @param string $clientId The client identifier.
+ * @return array An associative array keyed by window name (e.g., 'second', 'day') where each value is an array with keys `remaining` (int) and `timestamp` (int, Unix time). Returns an empty array if no data exists for the client.
+ */
     public function allForClient(string $clientId): array;
-}
+}
\ No newline at end of file
diff --git a/lib/RateLimit/RateLimiter.php b/lib/RateLimit/RateLimiter.php
index 50f4860..8f720f7 100644
--- a/lib/RateLimit/RateLimiter.php
+++ b/lib/RateLimit/RateLimiter.php
@@ -20,19 +20,34 @@ class RateLimiter
     private RateLimitStoreInterface $store;
     private bool $waitMode;
 
+    /**
+     * Create a RateLimiter configured with a storage backend and a handling mode for exceeded limits.
+     *
+     * @param RateLimitStoreInterface $store Storage backend for per-client rate-limit state.
+     * @param bool $waitMode If true, the limiter will wait until the limit window resets; if false, it will throw a RateLimitExceededException when limits are exceeded.
+     */
     public function __construct(RateLimitStoreInterface $store, bool $waitMode = true)
     {
         $this->store = $store;
         $this->waitMode = $waitMode;
     }
+    /**
+     * Indicates whether the limiter is configured to wait when a rate limit is exceeded.
+     *
+     * @return bool `true` if the limiter waits until the rate-limit window expires, `false` otherwise.
+     */
     public function isWaitMode(): bool
     {
         return $this->waitMode;
     }
 
     /**
-     * clientId = fingerprint of the certificate (sha1, serial+issuer, etc.)
-     * secondLimits/dayLimits are obtained from API response headers.
+     * Stores remaining rate-limit counts for a client for both the one-second and 24-hour windows.
+     *
+     * @param string $clientId Fingerprint identifying the client (e.g., certificate SHA1, serial+issuer).
+     * @param int $remainingSecond Remaining requests in the current one-second window.
+     * @param int $remainingDay Remaining requests in the current 24-hour window.
+     * @param int $timestamp UNIX timestamp (seconds) when the limits were observed.
      */
     public function handleRateLimits(
         string $clientId,
@@ -45,7 +60,13 @@ public function handleRateLimits(
     }
 
     /**
-     * Verification before the next request.
+     * Ensures the client is allowed to make the next request by enforcing per-second and per-day rate limits.
+     *
+     * If a window is exhausted and wait mode is enabled, pauses execution for the required seconds to clear the window;
+     * otherwise throws a RateLimitExceededException.
+     *
+     * @param string $clientId Identifier of the client whose rate limits are checked.
+     * @throws RateLimitExceededException If a rate limit is exceeded and wait mode is disabled.
      */
     public function checkBeforeRequest(string $clientId): void
     {
@@ -82,4 +103,4 @@ public function checkBeforeRequest(string $clientId): void
             }
         }
     }
-}
+}
\ No newline at end of file
diff --git a/lib/RateLimit/SqlDialect.php b/lib/RateLimit/SqlDialect.php
index 88dca4d..6e02404 100644
--- a/lib/RateLimit/SqlDialect.php
+++ b/lib/RateLimit/SqlDialect.php
@@ -17,6 +17,16 @@
 
 interface SqlDialect
 {
-    public function now(): int; // PHP timestamp → we store it directly as int
+    /**
+ * Get the current time as a Unix timestamp.
+ *
+ * @return int The current Unix timestamp (seconds since the Unix epoch).
+ */
+public function now(): int; /**
+ * Generate a SQL parameter placeholder for the given parameter name.
+ *
+ * @param string $name Logical parameter name (without any placeholder prefix characters).
+ * @return string The SQL placeholder string to use in queries (for example `:name`, `?`, or `@name` depending on the dialect).
+ */
     public function placeholder(string $name): string; // :name, ?, @name ...
-}
+}
\ No newline at end of file