diff --git a/src/internal/parser.gleam b/src/internal/parser.gleam
index 81db22b..718e52c 100644
--- a/src/internal/parser.gleam
+++ b/src/internal/parser.gleam
@@ -4,6 +4,8 @@ import gleam/list.{Continue, Stop}
 import gleam/option.{None, Some}
 import gleam/result
 import gleam/string
+import internal/utils
+import splitter
 
 import types.{type Uri, Uri, empty_uri}
 
@@ -511,8 +513,8 @@ fn do_parse_reg_name(str: String, reg_name: String) {
 fn parse_pct_encoded(str: String) {
   case str {
     "%" <> rest -> {
-      use #(hex1, rest) <- result.try(parse_hex_digit(rest))
-      use #(hex2, rest) <- result.try(parse_hex_digit(rest))
+      use #(hex1, rest) <- result.try(utils.parse_hex_digit(rest))
+      use #(hex2, rest) <- result.try(utils.parse_hex_digit(rest))
 
       Ok(#("%" <> hex1 <> hex2, rest))
     }
@@ -689,35 +691,7 @@ fn parse_min_max(str, min, max, parse_fn) {
 }
 
 fn parse_hex_digits(str, min, max) {
-  parse_min_max(str, min, max, parse_hex_digit)
-}
-
-pub fn parse_hex_digit(str) {
-  case str {
-    "0" as l <> rest
-    | "1" as l <> rest
-    | "2" as l <> rest
-    | "3" as l <> rest
-    | "4" as l <> rest
-    | "5" as l <> rest
-    | "6" as l <> rest
-    | "7" as l <> rest
-    | "8" as l <> rest
-    | "9" as l <> rest
-    | "a" as l <> rest
-    | "b" as l <> rest
-    | "c" as l <> rest
-    | "d" as l <> rest
-    | "e" as l <> rest
-    | "f" as l <> rest
-    | "A" as l <> rest
-    | "B" as l <> rest
-    | "C" as l <> rest
-    | "D" as l <> rest
-    | "E" as l <> rest
-    | "F" as l <> rest -> Ok(#(l, rest))
-    _ -> Error(Nil)
-  }
+  parse_min_max(str, min, max, utils.parse_hex_digit)
 }
 
 fn parse_digit(str: String) -> Result(#(String, String), Nil) {
@@ -848,3 +822,41 @@ fn combine_uris(uris: List(Uri)) -> Uri {
     }
   })
 }
+
+pub fn parse_query_parts(query: String) -> Result(List(#(String, String)), Nil) {
+  let splitter = splitter.new(["&"])
+
+  do_parse_query_parts(splitter, query, [])
+}
+
+fn do_parse_query_parts(
+  splitter: splitter.Splitter,
+  query: String,
+  acc: List(#(String, String)),
+) -> Result(List(#(String, String)), Nil) {
+  case splitter.split(splitter, query) {
+    #("", _, "") -> Ok(list.reverse(acc))
+    #("", _, rest) -> do_parse_query_parts(splitter, rest, acc)
+    #(pair, _, rest) -> {
+      use pair <- result.try(do_parse_query_pair(pair))
+
+      let acc = [pair, ..acc]
+
+      case rest {
+        "" -> Ok(list.reverse(acc))
+        _ -> do_parse_query_parts(splitter, rest, acc)
+      }
+    }
+  }
+}
+
+fn do_parse_query_pair(pair: String) -> Result(#(String, String), Nil) {
+  let #(key, val) = case string.split_once(pair, "=") {
+    Error(_) -> #(pair, "")
+    Ok(p) -> p
+  }
+  use key <- result.try(utils.percent_decode(string.replace(key, "+", " ")))
+  use val <- result.try(utils.percent_decode(string.replace(val, "+", " ")))
+
+  Ok(#(key, val))
+}
diff --git a/src/internal/utils.gleam b/src/internal/utils.gleam
index 68bd5e1..96da75f 100644
--- a/src/internal/utils.gleam
+++ b/src/internal/utils.gleam
@@ -4,10 +4,22 @@ import gleam/list
 import gleam/option.{None, Some}
 import gleam/result
 import gleam/string
-import internal/parser
 import splitter.{type Splitter}
 import types.{type Uri, Uri}
 
+pub const scheme_port = [
+  #("http", 80),
+  #("https", 443),
+  #("ftp", 21),
+  #("ws", 80),
+  #("wss", 443),
+]
+
+pub fn get_port_for_scheme(scheme: String) -> Result(Int, Nil) {
+  list.find(scheme_port, fn(sp) { sp.0 == scheme })
+  |> result.map(fn(sp) { sp.1 })
+}
+
 pub fn merge(base: Uri, relative: Uri) -> Result(Uri, Nil) {
   use <- bool.guard(when: base.scheme == None, return: Error(Nil))
   let uri = case relative.scheme {
@@ -133,9 +145,9 @@ fn do_normalise_percent(
       case after {
         "" -> res <> before
         _ -> {
-          let #(pc_val, rest) = case parser.parse_hex_digit(after) {
+          let #(pc_val, rest) = case parse_hex_digit(after) {
             Ok(#(pc1, rest)) -> {
-              case parser.parse_hex_digit(rest) {
+              case parse_hex_digit(rest) {
                 Ok(#(pc2, rest)) -> {
                   let hex = pc1 <> pc2
                   let v = unescape_percent(hex)
@@ -171,6 +183,34 @@ fn unescape_percent(str: String) -> String {
   }
 }
 
+pub fn parse_hex_digit(str) {
+  case str {
+    "0" as l <> rest
+    | "1" as l <> rest
+    | "2" as l <> rest
+    | "3" as l <> rest
+    | "4" as l <> rest
+    | "5" as l <> rest
+    | "6" as l <> rest
+    | "7" as l <> rest
+    | "8" as l <> rest
+    | "9" as l <> rest
+    | "a" as l <> rest
+    | "b" as l <> rest
+    | "c" as l <> rest
+    | "d" as l <> rest
+    | "e" as l <> rest
+    | "f" as l <> rest
+    | "A" as l <> rest
+    | "B" as l <> rest
+    | "C" as l <> rest
+    | "D" as l <> rest
+    | "E" as l <> rest
+    | "F" as l <> rest -> Ok(#(l, rest))
+    _ -> Error(Nil)
+  }
+}
+
 fn encoding_not_needed(i: Int) -> Bool {
   // $-_.+!*'()
   case i {
@@ -202,8 +242,8 @@ fn do_percent_decode(
   case splitter.split(splitter, str) {
     #(before, "", "") -> Ok(acc <> before)
     #(before, "%", after) -> {
-      use #(hd1, rest) <- result.try(parser.parse_hex_digit(after))
-      use #(hd2, rest) <- result.try(parser.parse_hex_digit(rest))
+      use #(hd1, rest) <- result.try(parse_hex_digit(after))
+      use #(hd2, rest) <- result.try(parse_hex_digit(rest))
 
       use char <- result.try(int.base_parse(hd1 <> hd2, 16))
       case int.bitwise_and(char, 128) {
@@ -263,14 +303,14 @@ pub fn decode_3byte_utf(
     "%" <> rest -> Ok(rest)
     _ -> Error(Nil)
   })
-  use #(hd3, rest) <- result.try(parser.parse_hex_digit(rest))
-  use #(hd4, rest) <- result.try(parser.parse_hex_digit(rest))
+  use #(hd3, rest) <- result.try(parse_hex_digit(rest))
+  use #(hd4, rest) <- result.try(parse_hex_digit(rest))
   use rest <- result.try(case rest {
     "%" <> rest -> Ok(rest)
     _ -> Error(Nil)
   })
-  use #(hd5, rest) <- result.try(parser.parse_hex_digit(rest))
-  use #(hd6, rest) <- result.try(parser.parse_hex_digit(rest))
+  use #(hd5, rest) <- result.try(parse_hex_digit(rest))
+  use #(hd6, rest) <- result.try(parse_hex_digit(rest))
 
   use bytes <- result.try(int.base_parse(
     first_byte <> hd3 <> hd4 <> hd5 <> hd6,
@@ -308,8 +348,8 @@ pub fn decode_2byte_utf(
     "%" <> rest -> Ok(rest)
     _ -> Error(Nil)
   })
-  use #(hd3, rest) <- result.try(parser.parse_hex_digit(rest))
-  use #(hd4, rest) <- result.try(parser.parse_hex_digit(rest))
+  use #(hd3, rest) <- result.try(parse_hex_digit(rest))
+  use #(hd4, rest) <- result.try(parse_hex_digit(rest))
 
   use bytes <- result.try(int.base_parse(first_byte <> hd3 <> hd4, 16))
   let assert <<
@@ -341,20 +381,20 @@ fn decode_4byte_utf(
     "%" <> rest -> Ok(rest)
     _ -> Error(Nil)
   })
-  use #(hd3, rest) <- result.try(parser.parse_hex_digit(rest))
-  use #(hd4, rest) <- result.try(parser.parse_hex_digit(rest))
+  use #(hd3, rest) <- result.try(parse_hex_digit(rest))
+  use #(hd4, rest) <- result.try(parse_hex_digit(rest))
   use rest <- result.try(case rest {
     "%" <> rest -> Ok(rest)
     _ -> Error(Nil)
   })
-  use #(hd5, rest) <- result.try(parser.parse_hex_digit(rest))
-  use #(hd6, rest) <- result.try(parser.parse_hex_digit(rest))
+  use #(hd5, rest) <- result.try(parse_hex_digit(rest))
+  use #(hd6, rest) <- result.try(parse_hex_digit(rest))
   use rest <- result.try(case rest {
     "%" <> rest -> Ok(rest)
     _ -> Error(Nil)
   })
-  use #(hd7, rest) <- result.try(parser.parse_hex_digit(rest))
-  use #(hd8, rest) <- result.try(parser.parse_hex_digit(rest))
+  use #(hd7, rest) <- result.try(parse_hex_digit(rest))
+  use #(hd8, rest) <- result.try(parse_hex_digit(rest))
 
   use bytes <- result.try(int.base_parse(
     first_byte <> hd3 <> hd4 <> hd5 <> hd6 <> hd7 <> hd8,
diff --git a/src/uri.gleam b/src/uri.gleam
index c934f3e..76eb580 100644
--- a/src/uri.gleam
+++ b/src/uri.gleam
@@ -1,9 +1,13 @@
 import gleam/bool
 import gleam/int
+import gleam/list
 import gleam/option.{None, Some}
+import gleam/result
+import gleam/string
 import gleam/uri
 import internal/parser
 import internal/utils
+import splitter
 import types.{type Uri, Uri}
 
 pub fn parse(uri: String) -> Result(Uri, Nil) {
@@ -104,11 +108,16 @@ pub fn percent_encode(value: String) -> String {
 }
 
 pub fn query_to_string(query: List(#(String, String))) -> String {
-  todo
+  list.map(query, fn(q) {
+    [utils.do_percent_encode(q.0), "=", utils.do_percent_encode(q.1)]
+  })
+  |> list.intersperse(["&"])
+  |> list.flatten
+  |> string.concat
 }
 
 pub fn parse_query(query: String) -> Result(List(#(String, String)), Nil) {
-  todo
+  parser.parse_query_parts(query)
 }
 
 pub fn origin(uri: Uri) -> Result(String, Nil) {
diff --git a/test/uri_test.gleam b/test/uri_test.gleam
index d44eafd..4a0893c 100644
--- a/test/uri_test.gleam
+++ b/test/uri_test.gleam
@@ -341,7 +341,7 @@ pub fn parse_path_tests() {
   ])
 }
 
-pub fn parse_query_tests() {
+pub fn parse_query_part_tests() {
   describe("query parsing", [
     it("simple parse", fn() {
       uri.parse("foo:?name=ferret")
@@ -553,7 +553,7 @@ pub fn parse_fragment_tests() {
   ])
 }
 
-fn parse_special_tests() {
+pub fn parse_special_tests() {
   describe("special parsing", [
     it("special 1", fn() {
       uri.parse("//?")
@@ -731,9 +731,9 @@ fn parse_special_tests() {
       uri.parse("#")
       |> should.equal(Ok(Uri(..types.empty_uri, path: "", fragment: Some(""))))
       uri.parse("##")
-      |> should.equal(Ok(Uri(..types.empty_uri, path: "", fragment: Some("#"))))
+      |> should.be_error
       uri.parse("###")
-      |> should.equal(Ok(Uri(..types.empty_uri, path: "", fragment: Some("##"))))
+      |> should.be_error
     }),
     it("special 2", fn() {
       uri.parse("a://:1/")
@@ -781,9 +781,7 @@ fn parse_special_tests() {
         Uri(..types.empty_uri, host: Some("localhost"), path: "/"),
       ))
       uri.parse("//:")
-      |> should.equal(Ok(
-        Uri(..types.empty_uri, host: Some("localhost"), path: ""),
-      ))
+      |> should.equal(Ok(Uri(..types.empty_uri, host: Some(""), path: "")))
     }),
   ])
 }
@@ -1157,29 +1155,6 @@ pub fn equivalence_tests() {
   ])
 }
 
-pub fn percent_encode_tests() {
-  describe("percent encoding", [
-    it("encoding", fn() {
-      percent_codec_fixtures
-      |> list.map(fn(t) {
-        let #(a, b) = t
-        uri.percent_encode(a)
-        |> should.equal(b)
-      })
-      Nil
-    }),
-    it("decoding", fn() {
-      percent_codec_fixtures
-      |> list.map(fn(t) {
-        let #(a, b) = t
-        uri.percent_decode(b)
-        |> should.equal(Ok(a))
-      })
-      Nil
-    }),
-  ])
-}
-
 const percent_codec_fixtures = [
   #(" ", "%20"),
   #(",", "%2C"),
@@ -1206,6 +1181,85 @@ const percent_codec_fixtures = [
   #("+", "+"),
   #("100% great+fun", "100%25%20great+fun"),
 ]
+
+pub fn percent_encode_tests() {
+  describe("percent encoding", [
+    it("encoding", fn() {
+      percent_codec_fixtures
+      |> list.map(fn(t) {
+        let #(a, b) = t
+        uri.percent_encode(a)
+        |> should.equal(b)
+      })
+      Nil
+    }),
+    it("decoding", fn() {
+      percent_codec_fixtures
+      |> list.map(fn(t) {
+        let #(a, b) = t
+        uri.percent_decode(b)
+        |> should.equal(Ok(a))
+      })
+      Nil
+    }),
+  ])
+}
+
+pub fn parse_query_tests() {
+  describe("parse_query", [
+    it("basic parse", fn() {
+      uri.parse_query("el1=123&el2=321")
+      |> should.be_ok
+      |> should.equal([#("el1", "123"), #("el2", "321")])
+      uri.parse_query("el%201=123&el+2=321")
+      |> should.be_ok
+      |> should.equal([#("el 1", "123"), #("el 2", "321")])
+      uri.parse_query("el%E2%82%AC1=12%CE%A33&el%F0%90%80%852=321")
+      |> should.be_ok
+      |> should.equal([#("el€1", "12Σ3"), #("el𐀅2", "321")])
+    }),
+    it("empty parts", fn() {
+      uri.parse_query("el1=123&&el2=321")
+      |> should.be_ok
+      |> should.equal([#("el1", "123"), #("el2", "321")])
+      uri.parse_query("el1=&el2=")
+      |> should.be_ok
+      |> should.equal([#("el1", ""), #("el2", "")])
+      uri.parse_query("")
+      |> should.be_ok
+      |> should.equal([])
+      uri.parse_query("=123&el2=321")
+      |> should.be_ok
+      |> should.equal([#("", "123"), #("el2", "321")])
+      uri.parse_query("=&el2=321")
+      |> should.be_ok
+      |> should.equal([#("", ""), #("el2", "321")])
+    }),
+  ])
+}
+
+pub fn query_to_string_tests() {
+  describe("query_to_string", [
+    it("basic query", fn() {
+      uri.query_to_string([#("el1", "123"), #("el2", "321")])
+      |> should.equal("el1=123&el2=321")
+      uri.query_to_string([#("el 1", "123"), #("el 2", "321")])
+      |> should.equal("el%201=123&el%202=321")
+      uri.query_to_string([#("el€1", "12Σ3"), #("el𐀅2", "321")])
+      |> should.equal("el%E2%82%AC1=12%CE%A33&el%F0%90%80%852=321")
+    }),
+    it("empty parts", fn() {
+      uri.query_to_string([#("el1", ""), #("el2", "")])
+      |> should.equal("el1=&el2=")
+      uri.query_to_string([])
+      |> should.equal("")
+      uri.query_to_string([#("", "123"), #("el2", "321")])
+      |> should.equal("=123&el2=321")
+      uri.query_to_string([#("", ""), #("el2", "321")])
+      |> should.equal("=&el2=321")
+    }),
+  ])
+}
 // gleeunit test functions end in `_test`
 // pub fn uri_test() {
 //   match("uri:")