diff --git a/bridge.go b/bridge.go
index 0b74e38..a693a36 100644
--- a/bridge.go
+++ b/bridge.go
@@ -194,13 +194,24 @@ func describeTool(desc ToolDescriptor, defaultTag string) RouteDescription {
 	}
 }
 
+// maxToolRequestBodyBytes is the maximum request body size accepted by the
+// tool bridge handler. Requests larger than this are rejected with 413.
+const maxToolRequestBodyBytes = 10 << 20 // 10 MiB
+
 func wrapToolHandler(handler gin.HandlerFunc, validator *toolInputValidator) gin.HandlerFunc {
 	return func(c *gin.Context) {
-		body, err := io.ReadAll(c.Request.Body)
+		limited := http.MaxBytesReader(c.Writer, c.Request.Body, maxToolRequestBodyBytes)
+		body, err := io.ReadAll(limited)
 		if err != nil {
-			c.AbortWithStatusJSON(http.StatusBadRequest, FailWithDetails(
+			status := http.StatusBadRequest
+			msg := "Unable to read request body"
+			if err.Error() == "http: request body too large" {
+				status = http.StatusRequestEntityTooLarge
+				msg = "Request body exceeds the maximum allowed size"
+			}
+			c.AbortWithStatusJSON(status, FailWithDetails(
 				"invalid_request_body",
-				"Unable to read request body",
+				msg,
 				map[string]any{"error": err.Error()},
 			))
 			return
@@ -289,9 +300,12 @@ func (v *toolInputValidator) ValidateResponse(body []byte) error {
 		return coreerr.E("ToolBridge.ValidateResponse", "response is missing a successful envelope", nil)
 	}
 
+	// data is serialised with omitempty, so a nil/zero-value payload from
+	// constructors like OK(nil) or OK(false) will omit the key entirely.
+	// Treat a missing data key as a valid nil payload for successful responses.
 	data, ok := envelope["data"]
 	if !ok {
-		return coreerr.E("ToolBridge.ValidateResponse", "response is missing data", nil)
+		return nil
 	}
 
 	encoded, err := json.Marshal(data)
@@ -691,10 +705,17 @@ func (w *toolResponseRecorder) reset() {
 func (w *toolResponseRecorder) writeErrorResponse(status int, resp Response[any]) {
 	data, err := json.Marshal(resp)
 	if err != nil {
+		w.status = http.StatusInternalServerError
+		w.wroteHeader = true
 		http.Error(w.ResponseWriter, "internal server error", http.StatusInternalServerError)
 		return
 	}
 
+	// Update recorder state so middleware observing c.Writer.Status() or
+	// Written() sees the correct values after an error response is emitted.
+	w.status = status
+	w.wroteHeader = true
+
 	w.ResponseWriter.Header().Set("Content-Type", "application/json")
 	w.ResponseWriter.WriteHeader(status)
 	_, _ = w.ResponseWriter.Write(data)
diff --git a/cache.go b/cache.go
index d9d86c9..9f71f4d 100644
--- a/cache.go
+++ b/cache.go
@@ -85,6 +85,12 @@ func (s *cacheStore) set(key string, entry *cacheEntry) {
 	}
 
 	if elem, ok := s.index[key]; ok {
+		// Reject an oversized replacement before touching LRU state so the
+		// existing entry remains intact when the new value cannot fit.
+		if s.maxBytes > 0 && entry.size > s.maxBytes {
+			s.mu.Unlock()
+			return
+		}
 		if existing, exists := s.entries[key]; exists {
 			s.currentBytes -= existing.size
 			if s.currentBytes < 0 {
diff --git a/cmd/api/cmd_sdk.go b/cmd/api/cmd_sdk.go
index bfad014..dfd5a38 100644
--- a/cmd/api/cmd_sdk.go
+++ b/cmd/api/cmd_sdk.go
@@ -55,7 +55,8 @@ func addSDKCommand(parent *cli.Command) {
 
 		// If no spec file was provided, generate one only after confirming the
 		// generator is available.
-		if specFile == "" {
+		resolvedSpecFile := specFile
+		if resolvedSpecFile == "" {
 			builder, err := sdkSpecBuilder(cfg)
 			if err != nil {
 				return err
@@ -76,10 +77,10 @@ func addSDKCommand(parent *cli.Command) {
 			if err := goapi.ExportSpecToFileIter(tmpPath, "json", builder, groups); err != nil {
 				return coreerr.E("sdk.Generate", "generate spec", err)
 			}
-			specFile = tmpPath
+			resolvedSpecFile = tmpPath
 		}
 
-		gen.SpecPath = specFile
+		gen.SpecPath = resolvedSpecFile
 
 		// Generate for each language.
 		for _, l := range languages {
diff --git a/cmd/api/cmd_test.go b/cmd/api/cmd_test.go
index 0d5396d..09361b7 100644
--- a/cmd/api/cmd_test.go
+++ b/cmd/api/cmd_test.go
@@ -810,6 +810,13 @@ func TestAPISpecCmd_Good_ServerFlagAddsServers(t *testing.T) {
 }
 
 func TestAPISpecCmd_Good_RegisteredSpecGroups(t *testing.T) {
+	snapshot := api.RegisteredSpecGroups()
+	api.ResetSpecGroups()
+	t.Cleanup(func() {
+		api.ResetSpecGroups()
+		api.RegisterSpecGroups(snapshot...)
+	})
+
 	api.RegisterSpecGroups(specCmdStubGroup{})
 
 	root := &cli.Command{Use: "root"}
diff --git a/codegen.go b/codegen.go
index ffa61e5..e031dea 100644
--- a/codegen.go
+++ b/codegen.go
@@ -93,7 +93,7 @@ func (g *SDKGenerator) Generate(ctx context.Context, language string) error {
 		return coreerr.E("SDKGenerator.Generate", "create output directory", err)
 	}
 
-	args := g.buildArgs(generator, outputDir)
+	args := g.buildArgs(specPath, generator, outputDir)
 	cmd := exec.CommandContext(ctx, "openapi-generator-cli", args...)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
@@ -106,10 +106,10 @@ func (g *SDKGenerator) Generate(ctx context.Context, language string) error {
 }
 
 // buildArgs constructs the openapi-generator-cli command arguments.
-func (g *SDKGenerator) buildArgs(generator, outputDir string) []string {
+func (g *SDKGenerator) buildArgs(specPath, generator, outputDir string) []string {
 	args := []string{
 		"generate",
-		"-i", g.SpecPath,
+		"-i", specPath,
 		"-g", generator,
 		"-o", outputDir,
 	}
diff --git a/export.go b/export.go
index 3095a6c..fadff80 100644
--- a/export.go
+++ b/export.go
@@ -94,21 +94,37 @@ func ExportSpecToFileIter(path, format string, builder *SpecBuilder, groups iter
 }
 
 func exportSpecToFile(path, op string, write func(io.Writer) error) (err error) {
-	if err := coreio.Local.EnsureDir(filepath.Dir(path)); err != nil {
+	dir := filepath.Dir(path)
+	if err := coreio.Local.EnsureDir(dir); err != nil {
 		return coreerr.E(op, "create directory", err)
 	}
-	f, err := os.Create(path)
+
+	// Write to a temp file in the same directory so the rename is atomic on
+	// most filesystems. The destination is never truncated unless the full
+	// export succeeds.
+	f, err := os.CreateTemp(dir, ".export-*.tmp")
 	if err != nil {
-		return coreerr.E(op, "create file", err)
+		return coreerr.E(op, "create temp file", err)
 	}
+	tmpPath := f.Name()
+
 	defer func() {
-		if closeErr := f.Close(); closeErr != nil && err == nil {
-			err = coreerr.E(op, "close file", closeErr)
+		if err != nil {
+			_ = os.Remove(tmpPath)
 		}
 	}()
 
-	if err = write(f); err != nil {
-		return err
+	if writeErr := write(f); writeErr != nil {
+		_ = f.Close()
+		return writeErr
+	}
+
+	if closeErr := f.Close(); closeErr != nil {
+		return coreerr.E(op, "close temp file", closeErr)
+	}
+
+	if renameErr := os.Rename(tmpPath, path); renameErr != nil {
+		return coreerr.E(op, "rename temp file", renameErr)
 	}
 	return nil
 }
diff --git a/openapi.go b/openapi.go
index 82d0cc2..eaba297 100644
--- a/openapi.go
+++ b/openapi.go
@@ -1910,10 +1910,14 @@ func sseResponseHeaders() map[string]any {
 }
 
 // effectiveGraphQLPath returns the configured GraphQL path or the default
-// GraphQL path when GraphQL is enabled without an explicit path.
+// GraphQL path when GraphQL is enabled without an explicit path. Returns an
+// empty string when neither GraphQL nor the playground is enabled.
 func (sb *SpecBuilder) effectiveGraphQLPath() string {
+	if !sb.GraphQLEnabled && !sb.GraphQLPlayground {
+		return ""
+	}
 	graphqlPath := strings.TrimSpace(sb.GraphQLPath)
-	if graphqlPath == "" && (sb.GraphQLEnabled || sb.GraphQLPlayground) {
+	if graphqlPath == "" {
 		return defaultGraphQLPath
 	}
 	return graphqlPath
@@ -1940,30 +1944,42 @@ func (sb *SpecBuilder) effectiveGraphQLPlaygroundPath() string {
 }
 
 // effectiveSwaggerPath returns the configured Swagger UI path or the default
-// path when Swagger is enabled without an explicit override.
+// path when Swagger is enabled without an explicit override. Returns an empty
+// string when Swagger is disabled.
 func (sb *SpecBuilder) effectiveSwaggerPath() string {
+	if !sb.SwaggerEnabled {
+		return ""
+	}
 	swaggerPath := strings.TrimSpace(sb.SwaggerPath)
-	if swaggerPath == "" && sb.SwaggerEnabled {
+	if swaggerPath == "" {
 		return defaultSwaggerPath
 	}
 	return swaggerPath
 }
 
 // effectiveWSPath returns the configured WebSocket path or the default path
-// when WebSockets are enabled without an explicit override.
+// when WebSockets are enabled without an explicit override. Returns an empty
+// string when WebSockets are disabled.
 func (sb *SpecBuilder) effectiveWSPath() string {
+	if !sb.WSEnabled {
+		return ""
+	}
 	wsPath := strings.TrimSpace(sb.WSPath)
-	if wsPath == "" && sb.WSEnabled {
+	if wsPath == "" {
 		return defaultWSPath
 	}
 	return wsPath
 }
 
 // effectiveSSEPath returns the configured SSE path or the default path when
-// SSE is enabled without an explicit override.
+// SSE is enabled without an explicit override. Returns an empty string when
+// SSE is disabled.
 func (sb *SpecBuilder) effectiveSSEPath() string {
+	if !sb.SSEEnabled {
+		return ""
+	}
 	ssePath := strings.TrimSpace(sb.SSEPath)
-	if ssePath == "" && sb.SSEEnabled {
+	if ssePath == "" {
 		return defaultSSEPath
 	}
 	return ssePath
@@ -1992,7 +2008,10 @@ func (sb *SpecBuilder) effectiveAuthentikPublicPaths() []string {
 		return nil
 	}
 
-	paths := []string{"/health", "/swagger", resolveSwaggerPath(sb.SwaggerPath)}
+	paths := []string{"/health"}
+	if swaggerPath := sb.effectiveSwaggerPath(); swaggerPath != "" {
+		paths = append(paths, swaggerPath)
+	}
 	paths = append(paths, sb.AuthentikPublicPaths...)
 	return normalisePublicPaths(paths)
 }
diff --git a/pkg/provider/proxy.go b/pkg/provider/proxy.go
index c588b32..e2ef86b 100644
--- a/pkg/provider/proxy.go
+++ b/pkg/provider/proxy.go
@@ -3,6 +3,7 @@
 package provider
 
 import (
+	"fmt"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
@@ -56,6 +57,16 @@ func NewProxy(cfg ProxyConfig) *ProxyProvider {
 		}
 	}
 
+	// url.Parse accepts inputs like "127.0.0.1:9901" without error — they
+	// parse without a scheme or host, which causes httputil.ReverseProxy to
+	// fail silently at runtime. Require both to be present.
+	if target.Scheme == "" || target.Host == "" {
+		return &ProxyProvider{
+			config: cfg,
+			err:    fmt.Errorf("upstream %q must include a scheme and host (e.g. http://127.0.0.1:9901)", cfg.Upstream),
+		}
+	}
+
 	proxy := httputil.NewSingleHostReverseProxy(target)
 
 	// Preserve the original Director but strip the base path so the
diff --git a/ratelimit.go b/ratelimit.go
index 20ebd77..29bed2f 100644
--- a/ratelimit.go
+++ b/ratelimit.go
@@ -3,6 +3,8 @@
 package api
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
 	"math"
 	"net/http"
 	"strconv"
@@ -146,8 +148,8 @@ func rateLimitMiddleware(limit int) gin.HandlerFunc {
 			return
 		}
 
-		c.Next()
 		setRateLimitHeaders(c, decision.limit, decision.remaining, decision.resetAt)
+		c.Next()
 	}
 }
 
@@ -183,21 +185,41 @@ func timeUntilFull(tokens float64, limit int) time.Duration {
 	return time.Duration(math.Ceil(seconds * float64(time.Second)))
 }
 
-// clientRateLimitKey prefers caller-provided credentials for bucket
-// isolation, then falls back to the network address.
+// clientRateLimitKey derives a bucket key for the request. It prefers a
+// validated principal from context (set by auth middleware), then falls back
+// to the client IP. Raw credential headers are hashed with SHA-256 when used
+// as a last resort so that secrets are never stored in the bucket map.
 func clientRateLimitKey(c *gin.Context) string {
-	if apiKey := strings.TrimSpace(c.GetHeader("X-API-Key")); apiKey != "" {
-		return "api_key:" + apiKey
+	// Prefer a validated principal placed in context by auth middleware.
+	if principal, ok := c.Get("principal"); ok && principal != nil {
+		if s, ok := principal.(string); ok && s != "" {
+			return "principal:" + s
+		}
 	}
-	if bearer := bearerTokenFromHeader(c.GetHeader("Authorization")); bearer != "" {
-		return "bearer:" + bearer
+	if userID, ok := c.Get("userID"); ok && userID != nil {
+		if s, ok := userID.(string); ok && s != "" {
+			return "user:" + s
+		}
 	}
+
+	// Fall back to IP address.
 	if ip := c.ClientIP(); ip != "" {
 		return "ip:" + ip
 	}
 	if c.Request != nil && c.Request.RemoteAddr != "" {
 		return "ip:" + c.Request.RemoteAddr
 	}
+
+	// Last resort: hash credential headers so raw secrets are not retained.
+	if apiKey := strings.TrimSpace(c.GetHeader("X-API-Key")); apiKey != "" {
+		h := sha256.Sum256([]byte(apiKey))
+		return "cred:sha256:" + hex.EncodeToString(h[:])
+	}
+	if bearer := bearerTokenFromHeader(c.GetHeader("Authorization")); bearer != "" {
+		h := sha256.Sum256([]byte(bearer))
+		return "cred:sha256:" + hex.EncodeToString(h[:])
+	}
+
 	return "ip:unknown"
 }
 
diff --git a/response_meta.go b/response_meta.go
index 8438a7c..74f9e8a 100644
--- a/response_meta.go
+++ b/response_meta.go
@@ -23,6 +23,7 @@ type responseMetaRecorder struct {
 	gin.ResponseWriter
 	headers     http.Header
 	body        bytes.Buffer
+	size        int
 	status      int
 	wroteHeader bool
 	committed   bool
@@ -76,7 +77,9 @@ func (w *responseMetaRecorder) Write(data []byte) (int, error) {
 	if !w.wroteHeader {
 		w.WriteHeader(http.StatusOK)
 	}
-	return w.body.Write(data)
+	n, err := w.body.Write(data)
+	w.size += n
+	return n, err
 }
 
 func (w *responseMetaRecorder) WriteString(s string) (int, error) {
@@ -89,7 +92,9 @@ func (w *responseMetaRecorder) WriteString(s string) (int, error) {
 	if !w.wroteHeader {
 		w.WriteHeader(http.StatusOK)
 	}
-	return w.body.WriteString(s)
+	n, err := w.body.WriteString(s)
+	w.size += n
+	return n, err
 }
 
 func (w *responseMetaRecorder) Flush() {
@@ -121,7 +126,10 @@ func (w *responseMetaRecorder) Status() int {
 }
 
 func (w *responseMetaRecorder) Size() int {
-	return w.body.Len()
+	if w.passthrough {
+		return w.ResponseWriter.Size()
+	}
+	return w.size
 }
 
 func (w *responseMetaRecorder) Written() bool {
@@ -194,6 +202,7 @@ func responseMetaMiddleware() gin.HandlerFunc {
 
 		recorder.body.Reset()
 		_, _ = recorder.body.Write(body)
+		recorder.size = len(body)
 		recorder.Header().Set("Content-Length", strconv.Itoa(len(body)))
 		recorder.commit(true)
 	}
diff --git a/src/php/src/Api/Concerns/HasApiResponses.php b/src/php/src/Api/Concerns/HasApiResponses.php
index 4a47c75..e63de74 100644
--- a/src/php/src/Api/Concerns/HasApiResponses.php
+++ b/src/php/src/Api/Concerns/HasApiResponses.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Core\Api\Concerns;
 
 use Illuminate\Http\JsonResponse;
diff --git a/src/php/src/Api/Documentation/Views/stoplight.blade.php b/src/php/src/Api/Documentation/Views/stoplight.blade.php
index 5afade9..803eed3 100644
--- a/src/php/src/Api/Documentation/Views/stoplight.blade.php
+++ b/src/php/src/Api/Documentation/Views/stoplight.blade.php
@@ -26,7 +26,7 @@
         router="hash"
         layout="{{ $config['layout'] ?? 'sidebar' }}"
         theme="{{ $config['theme'] ?? 'dark' }}"
-        hideTryIt="{{ ($config['hide_try_it'] ?? false) ? 'true' : 'false' }}"
+        @if($config['hide_try_it'] ?? false) hideTryIt="true" @endif
     ></elements-api>
 
     <script src="https://unpkg.com/@stoplight/elements/web-components.min.js"></script>
diff --git a/src/php/src/Api/Exceptions/RateLimitExceededException.php b/src/php/src/Api/Exceptions/RateLimitExceededException.php
index ac764cd..b4d768c 100644
--- a/src/php/src/Api/Exceptions/RateLimitExceededException.php
+++ b/src/php/src/Api/Exceptions/RateLimitExceededException.php
@@ -51,9 +51,17 @@ class RateLimitExceededException extends HttpException
         )->withHeaders($this->rateLimitResult->headers());
 
         if ($request !== null) {
-            $origin = $request->headers->get('Origin', '*');
-            $response->headers->set('Access-Control-Allow-Origin', $origin);
-            $response->headers->set('Vary', 'Origin');
+            $origin = $request->headers->get('Origin');
+            $allowedOrigins = (array) config('cors.allowed_origins', []);
+            if ($origin !== null && in_array($origin, $allowedOrigins, true)) {
+                $response->headers->set('Access-Control-Allow-Origin', $origin);
+            }
+
+            $existingVary = $response->headers->get('Vary');
+            $response->headers->set(
+                'Vary',
+                $existingVary ? $existingVary.', Origin' : 'Origin'
+            );
         }
 
         return $response;
diff --git a/src/php/src/Api/Services/ApiUsageService.php b/src/php/src/Api/Services/ApiUsageService.php
index e9d241d..f5d7445 100644
--- a/src/php/src/Api/Services/ApiUsageService.php
+++ b/src/php/src/Api/Services/ApiUsageService.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace Core\Api\Services;
 
 use Carbon\Carbon;
+use Core\Api\Models\ApiKey;
 use Core\Api\Models\ApiUsage;
 use Core\Api\Models\ApiUsageDaily;
 
@@ -282,7 +283,7 @@ class ApiUsageService
 
         // Fetch API keys separately to avoid broken eager loading with aggregation
         $apiKeyIds = $aggregated->pluck('api_key_id')->filter()->unique()->all();
-        $apiKeys = \Mod\Api\Models\ApiKey::whereIn('id', $apiKeyIds)
+        $apiKeys = ApiKey::whereIn('id', $apiKeyIds)
             ->select('id', 'name', 'prefix')
             ->get()
             ->keyBy('id');
diff --git a/src/php/src/Api/Services/SeoReportService.php b/src/php/src/Api/Services/SeoReportService.php
index c1cc1d7..2f0fe95 100644
--- a/src/php/src/Api/Services/SeoReportService.php
+++ b/src/php/src/Api/Services/SeoReportService.php
@@ -20,16 +20,24 @@ class SeoReportService
 {
     /**
      * Analyse a URL and return a technical SEO report.
+     *
+     * @throws RuntimeException when the URL is blocked for SSRF reasons or the fetch fails.
      */
     public function analyse(string $url): array
     {
+        $this->validateUrlForSsrf($url);
+
         try {
             $response = Http::withHeaders([
                 'User-Agent' => config('app.name', 'Core API').' SEO Reporter/1.0',
                 'Accept' => 'text/html,application/xhtml+xml',
             ])
                 ->timeout((int) config('api.seo.timeout', 10))
-                ->get($url);
+                ->withoutRedirecting()
+                ->get($url)
+                ->throw();
+        } catch (RuntimeException $exception) {
+            throw $exception;
         } catch (Throwable $exception) {
             throw new RuntimeException('Unable to fetch the requested URL.', 0, $exception);
         }
@@ -349,6 +357,107 @@ class SeoReportService
         ];
     }
 
+    /**
+     * Validate that a URL is safe to fetch and does not target internal/private
+     * network resources (SSRF protection).
+     *
+     * Blocks:
+     *  - Non-HTTP/HTTPS schemes
+     *  - Loopback addresses (127.0.0.0/8, ::1)
+     *  - RFC-1918 private ranges (10/8, 172.16/12, 192.168/16)
+     *  - Link-local ranges (169.254.0.0/16, fe80::/10)
+     *  - IPv6 ULA (fc00::/7)
+     *
+     * @throws RuntimeException when the URL fails SSRF validation.
+     */
+    protected function validateUrlForSsrf(string $url): void
+    {
+        $parsed = parse_url($url);
+
+        if ($parsed === false || empty($parsed['scheme']) || empty($parsed['host'])) {
+            throw new RuntimeException('The supplied URL is not valid.');
+        }
+
+        if (! in_array(strtolower($parsed['scheme']), ['http', 'https'], true)) {
+            throw new RuntimeException('Only HTTP and HTTPS URLs are permitted.');
+        }
+
+        $host = $parsed['host'];
+        $records = dns_get_record($host, DNS_A | DNS_AAAA) ?: [];
+
+        // Fall back to gethostbyname for hosts not returned by dns_get_record.
+        if (empty($records)) {
+            $resolved = gethostbyname($host);
+            if ($resolved !== $host) {
+                $records[] = ['ip' => $resolved];
+            }
+        }
+
+        foreach ($records as $record) {
+            $ip = $record['ip'] ?? $record['ipv6'] ?? null;
+            if ($ip === null) {
+                continue;
+            }
+            if ($this->isPrivateIp($ip)) {
+                throw new RuntimeException('The supplied URL resolves to a private or reserved address.');
+            }
+        }
+    }
+
+    /**
+     * Return true when an IP address falls within a private, loopback, or
+     * link-local range.
+     */
+    protected function isPrivateIp(string $ip): bool
+    {
+        // inet_pton returns false for invalid addresses.
+        $packed = inet_pton($ip);
+        if ($packed === false) {
+            return true; // Treat unresolvable as unsafe.
+        }
+
+        if (strlen($packed) === 4) {
+            // IPv4 checks.
+            $long = ip2long($ip);
+            if ($long === false) {
+                return true;
+            }
+            $privateRanges = [
+                ['start' => ip2long('127.0.0.0'),   'end' => ip2long('127.255.255.255')], // loopback
+                ['start' => ip2long('10.0.0.0'),    'end' => ip2long('10.255.255.255')],  // RFC-1918
+                ['start' => ip2long('172.16.0.0'),  'end' => ip2long('172.31.255.255')],  // RFC-1918
+                ['start' => ip2long('192.168.0.0'), 'end' => ip2long('192.168.255.255')], // RFC-1918
+                ['start' => ip2long('169.254.0.0'), 'end' => ip2long('169.254.255.255')], // link-local
+            ];
+            foreach ($privateRanges as $range) {
+                if ($long >= $range['start'] && $long <= $range['end']) {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        // IPv6 checks: loopback (::1), link-local (fe80::/10), ULA (fc00::/7).
+        if ($ip === '::1') {
+            return true;
+        }
+        $prefix2 = strtolower(substr(bin2hex($packed), 0, 2));
+        // fe80::/10 — first byte 0xfe, second byte 0x80–0xbf
+        if ($prefix2 === 'fe') {
+            $secondNibble = hexdec(substr(bin2hex($packed), 2, 1));
+            if ($secondNibble >= 8 && $secondNibble <= 11) {
+                return true;
+            }
+        }
+        // fc00::/7 — first byte 0xfc or 0xfd
+        if (in_array($prefix2, ['fc', 'fd'], true)) {
+            return true;
+        }
+
+        return false;
+    }
+
     /**
      * Quote a literal for XPath queries.
      */
diff --git a/src/php/src/Api/config.php b/src/php/src/Api/config.php
index 220058c..d2a835d 100644
--- a/src/php/src/Api/config.php
+++ b/src/php/src/Api/config.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * API Configuration
  *