diff --git a/src/pango_aliasor/aliasor.py b/src/pango_aliasor/aliasor.py
index aae0485..c3aebe4 100644
--- a/src/pango_aliasor/aliasor.py
+++ b/src/pango_aliasor/aliasor.py
@@ -1,4 +1,3 @@
-#%%
 class Aliasor:
     def __init__(self, alias_file=None):
         import json
@@ -24,7 +23,13 @@ def __init__(self, alias_file=None):
 
         self.realias_dict = {v: k for k, v in self.alias_dict.items()}
 
-    def compress(self, name):
+    def compress(self, name, assign=False):
+        """
+        Returns the compressed lineage name. 
+        Set assign to True to automatically define new aliases for otherwise unhandled designations. 
+        For example, if you want to compress 'BA.5.2.5.6', and BA.5.2.5 does not have an accepted alias, 
+        it will assign BA.5.2.5 to the next available code (in this example, EN) and return EN.6.
+        """
         name_split = name.split(".")
         levels = len(name_split) - 1
         num_indirections = (levels - 1) // 3
@@ -32,9 +37,15 @@ def compress(self, name):
             return name
         alias = ".".join(name_split[0 : (3 * num_indirections + 1)])
         ending = ".".join(name_split[(3 * num_indirections + 1) :])
+        if assign and alias not in self.realias_dict:
+            #note- this cannot produce lineage aliases prefixed with X, which are handled separately as they represent recombinants.
+            self.assign_alias(alias)
         return self.realias_dict[alias] + "." + ending
 
     def uncompress(self, name):
+        """
+        Returns the uncompressed lineage name.
+        """
         name_split = name.split(".")
         letter = name_split[0]
         try:
@@ -89,6 +100,60 @@ def partial_compress(self, name, up_to: int = 0, accepted_aliases: set = {}):
         if name_split[(3 * up_to + 1) :] == []:
             return alias
         return alias + "." + ".".join(name_split[(3 * up_to + 1) :])
+    
+    @staticmethod
+    def _charToB(char):
+        return ord(char)-65
+
+    @staticmethod
+    def _bToChar(n, banned='IOX'):
+        l = chr(n+65)
+        while l in banned:
+            n += 1
+            l = chr(n+65)
+        return l
+
+    @staticmethod
+    def _numberToString(n, b=26, banned='IOX'):
+        #convert the number to base 26
+        if n == 0:
+            return [0]
+        digits = []
+        while n:
+            digits.append(int(n % b))
+            n //= b
+        #convert the base 26 to an alphabet string, incrementing past banned characters
+        return "".join([Aliasor._bToChar(d,banned) for d in digits[::-1]])
 
+    @staticmethod
+    def _stringToNumber(cstr, b=26):
+        #convert the string to a base26 number
+        digits = [Aliasor._charToB(c) for c in cstr]
+        #add the digits up to make a base10 number
+        num = 0
+        level = 0
+        for d in digits[::-1]:
+            num += d * b**level
+            level += 1
+        return num
 
-# %%
+    def next_available_alias(self, recombinant=False):
+        """
+        Returns the next available alias string. 
+        Tracks recombinants separately; set recombinant to True to get the next available recombinant alias.
+        """
+        if recombinant:
+            current = [Aliasor._stringToNumber(k[1:]) for k in self.alias_dict.keys() if k[0] == 'X']
+            return 'X' + Aliasor._numberToString(max(current) + 1)
+        else:
+            current = [Aliasor._stringToNumber(k) for k in self.alias_dict.keys() if k[0] != 'X']
+            return Aliasor._numberToString(max(current) + 1)
+
+    def assign_alias(self, name, recombinant=False):
+        """
+        Assigns the input name to the next available alias. 
+        Set recombinant to True to assign it to the next recombinant alias.
+        """
+        nextn = self.next_available_alias(recombinant)
+        self.alias_dict[nextn] = name
+        self.realias_dict[name] = nextn
\ No newline at end of file
diff --git a/tests/test_aliasor.py b/tests/test_aliasor.py
index 895bad5..7bdd457 100644
--- a/tests/test_aliasor.py
+++ b/tests/test_aliasor.py
@@ -90,4 +90,23 @@ def test_parent():
     assert aliasor.parent('') == ''
     assert aliasor.parent('A') == ''
     assert aliasor.parent('B') == ''
-    assert aliasor.parent('C.1') == 'B.1.1.1'
\ No newline at end of file
+    assert aliasor.parent('C.1') == 'B.1.1.1'
+
+def test_next_compression():
+    aliasor = Aliasor()
+    n1 = aliasor.next_available_alias()
+    assert n1 not in aliasor.alias_dict.keys()
+    n2 = aliasor.next_available_alias(True)
+    assert n2[0] == 'X'
+    assert n1 != n2
+
+def test_assign_compression():
+    aliasor = Aliasor()
+    n1 = aliasor.next_available_alias()
+    aliasor.assign_alias('test')
+    assert aliasor.realias_dict['test'] == n1
+    assert aliasor.alias_dict[n1] == 'test'
+    n2 = aliasor.next_available_alias(True)
+    aliasor.assign_alias('test2',True)
+    assert aliasor.realias_dict['test2'] == n2
+    assert aliasor.alias_dict[n2] == 'test2'
\ No newline at end of file