diff --git a/.editorconfig b/.editorconfig
index 2d82dfc..e9205a2 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -9,3 +9,6 @@ end_of_line = lf
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
+
+[*.rs]
+indent_style = space
diff --git a/.gitignore b/.gitignore
index 1173556..bfa2978 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,5 @@
 /pkgs/*/node_modules/
 /pkgs/*/dist/
 /pkgs/*/.turbo/
+
+/pkgs/solver-wasm/target/
diff --git a/pkgs/solver-wasm/Cargo.lock b/pkgs/solver-wasm/Cargo.lock
new file mode 100644
index 0000000..adcd2e1
--- /dev/null
+++ b/pkgs/solver-wasm/Cargo.lock
@@ -0,0 +1,211 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "block-buffer"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
+dependencies = [
+ "generic-array",
+]
+
+[[package]]
+name = "bumpalo"
+version = "3.19.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46c5e41b57b8bba42a04676d81cb89e9ee8e859a1a66f80a5a72e1cb76b34d43"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9555578bc9e57714c812a1f84e4fc5b4d21fcb063490c624de019f7464c91268"
+
+[[package]]
+name = "cpufeatures"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59ed5838eebb26a2bb2e58f6d5b5316989ae9d08bab10e0e6d103e656d1b0280"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "crypto-common"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
+[[package]]
+name = "digest"
+version = "0.10.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
+dependencies = [
+ "block-buffer",
+ "crypto-common",
+]
+
+[[package]]
+name = "generic-array"
+version = "0.14.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
+dependencies = [
+ "typenum",
+ "version_check",
+]
+
+[[package]]
+name = "libc"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1171693293099992e19cddea4e8b849964e9846f4acee11b3948bcc337be8776"
+
+[[package]]
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+version = "0.4.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13dc2df351e3202783a1fe0d44375f7295ffb4049267b0f3018346dc122a1d94"
+
+[[package]]
+name = "once_cell"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
+
+[[package]]
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+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1885c039570dc00dcb4ff087a89e185fd56bae234ddc7f056a945bf36467248d"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "rustversion"
+version = "1.0.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a0d197bd2c9dc6e53b84da9556a69ba4cdfab8619eb41a8bd1cc2027a0f6b1d"
+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7507d819769d01a365ab707794a4084392c824f54a7a6a7862f8c3d0892b283"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+]
+
+[[package]]
+name = "solver-wasm"
+version = "0.0.0"
+dependencies = [
+ "sha2",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "syn"
+version = "2.0.104"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17b6f705963418cdb9927482fa304bc562ece2fdd4f616084c50b7023b435a40"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "typenum"
+version = "1.18.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1dccffe3ce07af9386bfd29e80c0ab1a8205a2fc34e4bcd40364df902cfa8f3f"
+
+[[package]]
+name = "unicode-ident"
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+checksum = "5a5f39404a5da50712a4c1eecf25e90dd62b613502b7e925fd4e4d19b5c96512"
+
+[[package]]
+name = "version_check"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
+
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.100"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1edc8929d7499fc4e8f0be2262a241556cfc54a0bea223790e71446f2aab1ef5"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+ "rustversion",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.100"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2f0a0651a5c2bc21487bde11ee802ccaf4c51935d0d3d42a6101f98161700bc6"
+dependencies = [
+ "bumpalo",
+ "log",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.100"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fe63fc6d09ed3792bd0897b314f53de8e16568c2b3f7982f468c0bf9bd0b407"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.100"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ae87ea40c9f689fc23f209965b6fb8a99ad69aeeb0231408be24920604395de"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.100"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a05d73b933a847d6cccdda8f838a22ff101ad9bf93e33684f39c1f5f0eece3d"
+dependencies = [
+ "unicode-ident",
+]
diff --git a/pkgs/solver-wasm/Cargo.toml b/pkgs/solver-wasm/Cargo.toml
new file mode 100644
index 0000000..c15eab9
--- /dev/null
+++ b/pkgs/solver-wasm/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "solver-wasm"
+version = "0.0.0"
+edition = "2024"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+wasm-bindgen = "0.2"
+sha2 = "0.10"
diff --git a/pkgs/solver-wasm/package.json b/pkgs/solver-wasm/package.json
new file mode 100644
index 0000000..96a8aa0
--- /dev/null
+++ b/pkgs/solver-wasm/package.json
@@ -0,0 +1,6 @@
+{
+	"private": true,
+	"scripts": {
+		"build": "wasm-pack build --out-dir 'dist' --scope 'pow-captcha'"
+	}
+}
diff --git a/pkgs/solver-wasm/src/lib.rs b/pkgs/solver-wasm/src/lib.rs
new file mode 100644
index 0000000..b28b948
--- /dev/null
+++ b/pkgs/solver-wasm/src/lib.rs
@@ -0,0 +1,30 @@
+use sha2::{Digest, Sha256};
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+pub fn solve(nonce: &[u8], target: &[u8]) -> Box<[u8]> {
+    let mut buf = vec![0u8; 8 + nonce.len()];
+    buf[8..].copy_from_slice(nonce);
+
+    for i in 0u64.. {
+        let i_bytes = u64::to_le_bytes(i);
+        buf[0..=7].copy_from_slice(&i_bytes);
+        let hash = Sha256::digest(&buf);
+        if &hash[0..target.len()] == target {
+            return i_bytes.into();
+        }
+    }
+
+    unreachable!();
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn solve() {
+        assert_eq!(
+            super::solve(&[1, 2], &[3, 4]).as_ref(),
+            [45, 176, 0, 0, 0, 0, 0, 0]
+        );
+    }
+}