diff --git a/server/webserver.py b/server/webserver.py
index b52fde4..b9887d4 100644
--- a/server/webserver.py
+++ b/server/webserver.py
@@ -338,11 +338,14 @@ class WebServer:
                     sources = query.get(k).split(",")
                     spots = [s for s in spots if s.source and s.source in sources]
                 case "sig":
-                    # If a list of sigs is provided, the spot must have a sig and it must match one of them
+                    # If a list of sigs is provided, the spot must have a sig and it must match one of them.
+                    # The special "sig" "NO_SIG", when supplied in the list, mathches spots with no sig.
                     sigs = query.get(k).split(",")
-                    spots = [s for s in spots if s.sig and s.sig in sigs]
+                    include_no_sig = "NO_SIG" in sigs
+                    spots = [s for s in spots if (s.sig and s.sig in sigs) or (include_no_sig and not s.sig)]
                 case "needs_sig":
-                    # If true, a sig is required, regardless of what it is, it just can't be missing.
+                    # If true, a sig is required, regardless of what it is, it just can't be missing. Mutually
+                    # exclusive with supplying the special "NO_SIG" parameter to the "sig" query param.
                     needs_sig = query.get(k).upper() == "TRUE"
                     if needs_sig:
                         spots = [s for s in spots if s.sig]
@@ -441,8 +444,11 @@ class WebServer:
                     sources = query.get(k).split(",")
                     alerts = [a for a in alerts if a.source and a.source in sources]
                 case "sig":
+                    # If a list of sigs is provided, the alert must have a sig and it must match one of them.
+                    # The special "sig" "NO_SIG", when supplied in the list, mathches alerts with no sig.
                     sigs = query.get(k).split(",")
-                    alerts = [a for a in alerts if a.sig and a.sig in sigs]
+                    include_no_sig = "NO_SIG" in sigs
+                    spots = [a for a in alerts if (a.sig and a.sig in sigs) or (include_no_sig and not a.sig)]
                 case "dx_continent":
                     dxconts = query.get(k).split(",")
                     alerts = [a for a in alerts if a.dx_continent and a.dx_continent in dxconts]
diff --git a/webassets/apidocs/openapi.yml b/webassets/apidocs/openapi.yml
index 34aa61d..f23cf5f 100644
--- a/webassets/apidocs/openapi.yml
+++ b/webassets/apidocs/openapi.yml
@@ -58,13 +58,13 @@ paths:
             $ref: "#/components/schemas/Source"
         - name: sig
           in: query
-          description: "Limit the spots to only ones from one or more Special Interest Groups provided as an argument. To select more than one SIG, supply a comma-separated list."
+          description: "Limit the spots to only ones from one or more Special Interest Groups provided as an argument. To select more than one SIG, supply a comma-separated list. The special `sig` name `NO_SIG` matches spots with no sig set. You can use `sig=NO_SIG` to specifically only return generic spots with no associated SIG. You can also use combinations to request for example POTA + no SIG, but reject other SIGs. If you want to request 'every SIG and not No SIG', see the `needs_sig` query parameter for a shortcut."
           required: false
           schema:
-            $ref: "#/components/schemas/SIGName"
+            $ref: "#/components/schemas/SIGNameIncludingNoSIG"
         - name: needs_sig
           in: query
-          description: "Limit the spots to only ones with a Special Interest Group such as POTA. Because supplying all known SIGs as a `sigs` parameter is unwieldy, and leaving `sigs` blank will also return spots with *no* SIG, this parameter can be set true to return only spots with a SIG, regardless of what it is, so long as it's not blank. This is what Field Spotter uses to exclude generic cluster spots and only retrieve xOTA things."
+          description: "Limit the spots to only ones with a Special Interest Group such as POTA. Because supplying all known SIGs as a `sigs` parameter is unwieldy, and leaving `sigs` blank will also return spots with *no* SIG, this parameter can be set true to return only spots with a SIG, regardless of what it is, so long as it's not blank. This is the equivalent of supplying the `sig` query param with a list of every known SIG apart from the special `NO_SIG` value. This is what Field Spotter uses to exclude generic cluster spots and only retrieve xOTA things."
           required: false
           schema:
             type: boolean
@@ -190,10 +190,10 @@ paths:
             $ref: "#/components/schemas/Source"
         - name: sig
           in: query
-          description: "Limit the alerts to only ones from one or more Special Interest Groups. To select more than one SIG, supply a comma-separated list."
+          description: "Limit the alerts to only ones from one or more Special Interest Groups. To select more than one SIG, supply a comma-separated list. The special value 'NO_SIG' can be included to return alerts specifically without an associated SIG (i.e. general DXpeditions)."
           required: false
           schema:
-            $ref: "#/components/schemas/SIGName"
+            $ref: "#/components/schemas/SIGNameIncludingNoSIG"
         - name: dx_continent
           in: query
           description: "Limit the alerts to only ones where the DX operator is on the given continent(s). To select more than one continent, supply a comma-separated list."
@@ -591,6 +591,31 @@ components:
         - TOTA
       example: POTA
 
+    SIGNameIncludingNoSIG:
+      type: string
+      enum:
+        - POTA
+        - SOTA
+        - WWFF
+        - WWBOTA
+        - GMA
+        - HEMA
+        - WCA
+        - MOTA
+        - SIOTA
+        - ARLHS
+        - ILLW
+        - ZLOTA
+        - KRMNPA
+        - IOTA
+        - WOTA
+        - BOTA
+        - WAB
+        - WAI
+        - TOTA
+        - NO_SIG
+      example: POTA
+
     Continent:
       type: string
       enum: