diff --git a/index.d.ts b/index.d.ts
index cd7534b..b408716 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -7,6 +7,7 @@
 // }
 
 declare const crawlerUserAgents: {
+	id: string
 	pattern: string
 	addition_date?: string
 	url?: string
diff --git a/validate.go b/validate.go
index 41ab9d1..e42c7ed 100644
--- a/validate.go
+++ b/validate.go
@@ -13,6 +13,9 @@ var crawlersJson []byte
 
 // Crawler contains information about one crawler.
 type Crawler struct {
+	// An identifier for the crawler.
+	Id string `json:"id"`
+
 	// Regexp of User Agent of the crawler.
 	Pattern string `json:"pattern"`
 
@@ -28,6 +31,7 @@ type Crawler struct {
 
 // Private time needed to convert addition_date from/to the format used in JSON.
 type jsonCrawler struct {
+	Id           string   `json:"id"`
 	Pattern      string   `json:"pattern"`
 	AdditionDate string   `json:"addition_date"`
 	URL          string   `json:"url"`
@@ -52,10 +56,15 @@ func (c *Crawler) UnmarshalJSON(b []byte) error {
 		return err
 	}
 
+	c.Id = jc.Id
 	c.Pattern = jc.Pattern
 	c.URL = jc.URL
 	c.Instances = jc.Instances
 
+	if c.Id == "" {
+		return fmt.Errorf("empty id in record %s", string(b))
+	}
+
 	if c.Pattern == "" {
 		return fmt.Errorf("empty pattern in record %s", string(b))
 	}
diff --git a/validate.py b/validate.py
index 8f9c134..21c89eb 100644
--- a/validate.py
+++ b/validate.py
@@ -16,6 +16,7 @@
     "items": {
         "type": "object",
         "properties": {
+            "id": {"type": "string"}, # required
             "pattern": {"type": "string"}, # required
             "instances": {"type": "array"}, # required
             "url": {"type": "string"}, # optional
@@ -23,7 +24,7 @@
             "addition_date": {"type": "string"}, # optional
             "depends_on": {"type": "array"} # allows an instance to match twice
         },
-        "required": ["pattern", "instances"]
+        "required": ["id", "pattern", "instances"]
     }
 }