diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..ff3dcf1
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,29 @@
+# Changelog
+
+All notable changes to this crate are documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this crate adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [0.1.0] - 2026-05-02
+
+Initial release.
+
+- `encode(&[u8]) -> String` and `decode(&str) -> Result<Vec<u8>, DecodeError>`,
+  byte-for-byte compatible with the `base85` crate v2.0.0 on the success path.
+- aarch64 NEON-accelerated encode (4 blocks/iter) and decode (4 blocks/iter,
+  ~10× the reference scalar throughput on Apple M-series).
+- x86_64 AVX2-accelerated encode and decode (8 blocks/iter), with runtime
+  feature detection and scalar fallback for hosts lacking AVX2.
+- Portable scalar implementation for other architectures.
+- Strict overflow detection: 5-character blocks whose value exceeds `u32::MAX`
+  return `DecodeError::Overflow` rather than silently wrapping (release) or
+  panicking (debug) as the reference does.
+- Diagnostic `DecodeError` enum with byte positions; marked `#[non_exhaustive]`
+  for forward-compatibility.
+- MSRV: Rust 1.85.
+
+[Unreleased]: https://github.com/cipherstash/base85-simd/compare/v0.1.0...HEAD
+[0.1.0]: https://github.com/cipherstash/base85-simd/releases/tag/v0.1.0
diff --git a/Cargo.toml b/Cargo.toml
index e09f537..9a52971 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,14 +3,24 @@ name = "base85-simd"
 version = "0.1.0"
 edition = "2024"
 rust-version = "1.85"
-description = "Fast base85 (RFC 1924 / Z85-style) encoder and decoder, with a NEON SIMD encode path on aarch64."
+authors = ["Dan Draper <dan@cipherstash.com>"]
+description = "Fast base85 (RFC 1924 / Z85-style) encoder and decoder, with SIMD on aarch64 (NEON) and x86_64 (AVX2)."
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/cipherstash/base85-simd"
+homepage = "https://github.com/cipherstash/base85-simd"
 readme = "README.md"
 keywords = ["base85", "ascii85", "simd", "neon", "encoding"]
 categories = ["encoding"]
 exclude = ["*.xlsx", ".DS_Store", "mise.toml"]
 
+[package.metadata.docs.rs]
+# Build docs for both SIMD targets so the per-arch entry points
+# (NeonEncoder / Avx2Encoder, etc.) all render. docs.rs's default
+# x86_64-unknown-linux-gnu picks up the AVX2 path; we add aarch64
+# so the NEON path is also documented in the rendered output.
+targets = ["x86_64-unknown-linux-gnu", "aarch64-unknown-linux-gnu"]
+rustdoc-args = ["--cfg", "docsrs"]
+
 [dependencies]
 
 [dev-dependencies]
diff --git a/src/lib.rs b/src/lib.rs
index de6eab4..ef0ca09 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -18,7 +18,11 @@ use block::{decode_block, decode_tail, encode_block, encode_tail};
 use std::fmt;
 
 /// Errors returned by [`decode`].
+///
+/// Marked `#[non_exhaustive]` — match arms must include `_ => …` so future
+/// additions don't break downstream code.
 #[derive(Debug, Clone, PartialEq, Eq)]
+#[non_exhaustive]
 pub enum DecodeError {
     /// The input contained a byte that is not part of the base85 alphabet.
     InvalidChar {