diff --git a/docs/DEVICE_HEURISTICS.md b/docs/DEVICE_HEURISTICS.md
new file mode 100755
index 00000000..9e609f31
--- /dev/null
+++ b/docs/DEVICE_HEURISTICS.md
@@ -0,0 +1,120 @@
+# Icon and Type guessing: Device heuristics
+
+This module is responsible for inferring the most likely **device type** and **icon** based on minimal identifying data like MAC address, vendor, IP, or device name.
+
+It does this using a set of heuristics defined in an external JSON rules file, which it evaluates **in priority order**.
+
+---
+
+## JSON Rule Format
+
+Rules are defined in a file called `device_heuristics_rules.json` (located under `/back`), structured like:
+
+```json
+[
+  {
+    "dev_type": "Phone",
+    "icon_html": "<i class=\"fa-brands fa-apple\"></i>",
+    "matching_pattern": [
+      { "mac_prefix": "001A79", "vendor": "Apple" }
+    ],
+    "name_pattern": ["iphone", "pixel"]
+  }
+]
+```
+
+### Supported fields:
+
+| Field              | Type                 | Description                                                     |
+| ------------------ | -------------------- | --------------------------------------------------------------- |
+| `dev_type`         | `string`             | Type to assign if rule matches (e.g. `"Gateway"`, `"Phone"`)    |
+| `icon_html`        | `string`             | Icon (HTML string) to assign if rule matches. Encoded to base64 at load time. |
+| `matching_pattern` | `array`              | List of `{ mac_prefix, vendor }` objects for first strict and then loose matching    |
+| `name_pattern`     | `array` *(optional)* | List of lowercase substrings (used with regex)                  |
+| `ip_pattern`       | `array` *(optional)* | Regex patterns to match IPs                                     |
+
+**Order in this array defines priority** — rules are checked top-down and short-circuit on first match.
+
+---
+
+## Matching Flow (in Priority Order)
+
+The function `guess_device_attributes(...)` runs a series of matching functions in strict order:
+
+```text
+1. MAC + Vendor → match_mac_and_vendor()
+2. Vendor only → match_vendor()
+3. Name pattern → match_name()
+4. IP pattern → match_ip()
+5. Final fallback → defaults
+```
+
+### Even if defaults are passed in, matching continues
+
+For example, when `default_icon` is passed in from an external source (like `NEWDEV_devIcon`), that value **does not halt the guessing process**. The matchers still try to find a better match:
+
+```python
+# Even if default_icon is passed, match_ip() and others will still run
+if (not type_ or type_ == default_type) or (not icon or icon == default_icon):
+    type_, icon = match_ip(ip, default_type, default_icon)
+```
+
+This is by design — you can pass in known fallbacks (e.g. `"unknown_icon"`), but the system will still guess and overwrite them **if it finds a better match**.
+
+---
+
+## Defaults & Normalization
+
+Input sanitization ensures missing data doesn’t break detection:
+
+| Input         | Normalized to         |
+| ------------- | --------------------- |
+| `vendor=None` | `"unknown"`           |
+| `mac=None`    | `"00:00:00:00:00:00"` |
+| `ip=None`     | `"169.254.0.0"`       |
+| `name=None`   | `"(unknown)"`         |
+
+These placeholder values **still go through the matching pipeline**. This makes the logic robust and ensures IP- or name-based matching can still work even if MAC/Vendor are unknown.
+
+---
+
+## Match Behavior (per function)
+
+### `match_mac_and_vendor(mac_clean, vendor, ...)`
+
+* Looks for MAC prefix **and** vendor substring match
+* Most precise
+* Stops as soon as a match is found
+
+### `match_vendor(vendor, ...)`
+
+* Falls back to substring match on vendor only
+* Ignores rules where `mac_prefix` is present (ensures this is really a fallback)
+
+### `match_name(name, ...)`
+
+* Lowercase name is compared against all `name_pattern` values using regex
+* Good for user-assigned labels (e.g. "AP Office", "iPhone")
+
+### `match_ip(ip, ...)`
+
+* If IP is present and matches regex patterns under any rule, it returns that type/icon
+* Usually used for gateways or local IP ranges
+
+---
+
+## Icons
+
+* Each rule can define an `icon_html`, which is converted to a `icon_base64` on load
+* If missing, it falls back to the passed-in `default_icon` (`NEWDEV_devIcon` setting)
+* If a match is found but icon is still blank, default is used
+
+**TL;DR:** If a match sets the type but has no icon, the default icon is used. If the match has both, defaults are overridden.
+
+---
+
+## Priority Mechanics
+
+* JSON rules are evaluated **top-to-bottom**
+* Matching is **first-hit wins** — no scoring, no weights
+* Rules that are more specific (e.g. exact MAC prefixes) should be listed earlier
diff --git a/front/php/templates/language/fr_fr.json b/front/php/templates/language/fr_fr.json
old mode 100644
new mode 100755
diff --git a/mkdocs.yml b/mkdocs.yml
index f9985d6a..4eb17348 100755
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -75,6 +75,7 @@ nav:
         - Database: DATABASE.md
         - Settings: SETTINGS_SYSTEM.md
         - Versions: VERSIONS.md
+        - Icon and Type guessing: DEVICE_HEURISTICS.md
       - Integrations:
         - Webhook Secret: WEBHOOK_SECRET.md
         - API: API.md     
diff --git a/server/scan/device_heuristics.py b/server/scan/device_heuristics.py
index 61a7a8f5..5e7da0ff 100755
--- a/server/scan/device_heuristics.py
+++ b/server/scan/device_heuristics.py
@@ -141,7 +141,7 @@ def match_name(
 
 #-------------------------------------------------------------------------------
 #
-def match_ip_rule(
+def match_ip(
     ip: str,
     default_type: str,
     default_icon: str
@@ -215,7 +215,7 @@ def guess_device_attributes(
 
     # --- Loose IP-based fallback ---
     if (not type_ or type_ == default_type) or (not icon or icon == default_icon):
-        type_, icon = match_ip_rule(ip, default_type, default_icon)
+        type_, icon = match_ip(ip, default_type, default_icon)
 
     # Final fallbacks
     type_ = type_ or default_type