diff --git a/Cargo.lock b/Cargo.lock
index 05aebe8..b7666ee 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,15 +2,6 @@
 # It is not intended for manual editing.
 version = 4
 
-[[package]]
-name = "aho-corasick"
-version = "1.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
-dependencies = [
- "memchr",
-]
-
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -43,7 +34,6 @@ checksum = "7ee5b5339afb4c41626dde77b7a611bd4f2c202b897852b4bcf5d03eddc61010"
 name = "jsonm"
 version = "0.2.2"
 dependencies = [
- "regex",
  "serde",
  "serde_json",
 ]
@@ -72,35 +62,6 @@ dependencies = [
  "proc-macro2",
 ]
 
-[[package]]
-name = "regex"
-version = "1.12.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "843bc0191f75f3e22651ae5f1e72939ab2f72a4bc30fa80a066bd66edefc24d4"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-automata",
- "regex-syntax",
-]
-
-[[package]]
-name = "regex-automata"
-version = "0.4.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5276caf25ac86c8d810222b3dbb938e512c55c6831a10f3e6ed1c93b84041f1c"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-syntax",
-]
-
-[[package]]
-name = "regex-syntax"
-version = "0.8.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a2d987857b319362043e95f5353c0535c1f58eec5336fdfcf626430af7def58"
-
 [[package]]
 name = "ryu"
 version = "1.0.21"
diff --git a/Cargo.toml b/Cargo.toml
index 1c7131b..73f886c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,7 +17,6 @@ keywords = ["json", "jsonm", "compress"]
 
 [dependencies]
 serde = "1.0.228"
-regex = "1"
 
 [dependencies.serde_json]
 version = "1.0"
diff --git a/src/packer.rs b/src/packer.rs
index 294fa6d..758b9df 100644
--- a/src/packer.rs
+++ b/src/packer.rs
@@ -1,8 +1,6 @@
-extern crate regex;
 extern crate serde;
 extern crate serde_json;
 
-use self::regex::Regex;
 use self::serde::Serialize;
 use serde_json::Value;
 use std::collections::HashMap;
@@ -339,8 +337,7 @@ impl Packer {
 
         if value.is_string() {
             self.memoise(str_value, map_key, false);
-            let re = Regex::new(r"^[0-9.]|^~").unwrap();
-            if re.is_match(str_value) {
+            if str_value.starts_with(|c: char| c.is_ascii_digit() || c == '.' || c == '~') {
                 return json!("~".to_owned() + str_value);
             }
         }
diff --git a/src/unpacker.rs b/src/unpacker.rs
index 4a39900..4278a78 100644
--- a/src/unpacker.rs
+++ b/src/unpacker.rs
@@ -1,8 +1,6 @@
-extern crate regex;
 extern crate serde;
 extern crate serde_json;
 
-use self::regex::Regex;
 use self::serde::Deserialize;
 use serde_json::Value;
 use std::collections::HashMap;
@@ -17,6 +15,17 @@ const TYPE_VALUE: i64 = 1;
 const TYPE_STRING: i64 = 2;
 const MAX_PACK_COMPLEX_OBJECT_SIZE: usize = 12;
 
+fn starts_like_float(string: &str) -> bool {
+    let rest = string.strip_prefix('-').unwrap_or(string);
+    let after_digits = rest.trim_start_matches(|c: char| c.is_ascii_digit());
+    after_digits.len() < rest.len() && after_digits.starts_with('.')
+}
+
+fn starts_like_number(string: &str) -> bool {
+    let rest = string.strip_prefix('-').unwrap_or(string);
+    rest.starts_with(|c: char| c.is_ascii_digit() || c == '.')
+}
+
 #[derive(Default, Debug)]
 pub struct Unpacker {
     dict: HashMap<u64, String>,
@@ -296,8 +305,7 @@ impl Unpacker {
                 }
             };
 
-            let re = Regex::new(r"^-?[0-9]+\.").unwrap();
-            if re.is_match(string) {
+            if starts_like_float(string) {
                 let _p: Value = match string.parse::<f64>() {
                     Ok(parse_number) => {
                         self.add_to_dict(string);
@@ -307,8 +315,7 @@ impl Unpacker {
                 };
             };
 
-            let re = Regex::new(r"^-?[0-9\.]").unwrap();
-            if re.is_match(string) {
+            if starts_like_number(string) {
                 let _p: Value = match string.parse::<i64>() {
                     Ok(parse_number) => {
                         self.add_to_dict(string);