diff --git a/crates/puffin-cli/Cargo.toml b/crates/puffin-cli/Cargo.toml
index 81fa52925..c634ad4f8 100644
--- a/crates/puffin-cli/Cargo.toml
+++ b/crates/puffin-cli/Cargo.toml
@@ -7,9 +7,14 @@ edition = "2021"
 
 [dependencies]
 puffin-requirements = { path = "../puffin-requirements" }
+puffin-client = { path = "../puffin-client" }
 
 anyhow = "1.0.75"
 clap = { version = "4.4.6", features = ["derive"] }
 colored = { version = "2.0.4" }
 memchr = { version = "2.6.4" }
-pep508_rs = { version = "0.2.3" }
+async-std = { version = "1.12.0", features = [
+    "attributes",
+    "tokio1",
+    "unstable",
+] }
diff --git a/crates/puffin-cli/src/commands/install.rs b/crates/puffin-cli/src/commands/install.rs
index fba3081cf..70ebf4848 100644
--- a/crates/puffin-cli/src/commands/install.rs
+++ b/crates/puffin-cli/src/commands/install.rs
@@ -2,18 +2,25 @@ use std::path::Path;
 use std::str::FromStr;
 
 use anyhow::Result;
+use puffin_client::PypiClientBuilder;
 
 use crate::commands::ExitStatus;
 
-pub(crate) fn install(src: &Path) -> Result<ExitStatus> {
+pub(crate) async fn install(src: &Path) -> Result<ExitStatus> {
     // Read the `requirements.txt` from disk.
     let requirements_txt = std::fs::read_to_string(src)?;
 
     // Parse the `requirements.txt` into a list of requirements.
     let requirements = puffin_requirements::Requirements::from_str(&requirements_txt)?;
+
+    // Instantiate a client.
+    let client = PypiClientBuilder::default().build();
+
     for requirement in requirements.iter() {
+        let packument = client.simple(&requirement.name).await?;
         #[allow(clippy::print_stdout)]
         {
+            println!("{:#?}", packument);
             println!("{requirement:#?}");
         }
     }
diff --git a/crates/puffin-cli/src/main.rs b/crates/puffin-cli/src/main.rs
index 7089dd7bf..798f29994 100644
--- a/crates/puffin-cli/src/main.rs
+++ b/crates/puffin-cli/src/main.rs
@@ -28,11 +28,12 @@ struct InstallArgs {
     src: PathBuf,
 }
 
-fn main() -> ExitCode {
+#[async_std::main]
+async fn main() -> ExitCode {
     let cli = Cli::parse();
 
     let result = match &cli.command {
-        Commands::Install(install) => commands::install(&install.src),
+        Commands::Install(install) => commands::install(&install.src).await,
     };
 
     match result {
diff --git a/crates/puffin-client/Cargo.toml b/crates/puffin-client/Cargo.toml
new file mode 100644
index 000000000..b6c5924a9
--- /dev/null
+++ b/crates/puffin-client/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+name = "puffin-client"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+http-cache-reqwest = "0.11.3"
+reqwest = { version = "0.11.22", features = ["json", "gzip", "stream"] }
+reqwest-middleware = "0.2.3"
+reqwest-retry = "0.3.0"
+serde = "1.0.188"
+serde_json = "1.0.107"
+thiserror = { version = "1.0.49" }
+url = { version = "2.4.1" }
diff --git a/crates/puffin-client/README.md b/crates/puffin-client/README.md
new file mode 100644
index 000000000..ff33a5d9d
--- /dev/null
+++ b/crates/puffin-client/README.md
@@ -0,0 +1,5 @@
+# `pypi-client`
+
+A general-use client for interacting with PyPI.
+
+Loosely modeled after Orogene's `oro-client`.
diff --git a/crates/puffin-client/src/api/mod.rs b/crates/puffin-client/src/api/mod.rs
new file mode 100644
index 000000000..7870a5b04
--- /dev/null
+++ b/crates/puffin-client/src/api/mod.rs
@@ -0,0 +1,182 @@
+use crate::PypiClient;
+use reqwest::StatusCode;
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+use thiserror::Error;
+use url::Url;
+
+#[derive(Debug, Error)]
+pub enum PypiClientError {
+    /// An invalid URL was provided.
+    #[error(transparent)]
+    UrlParseError(#[from] url::ParseError),
+
+    /// The package was not found in the registry.
+    ///
+    /// Make sure the package name is spelled correctly and that you've
+    /// configured the right registry to fetch it from.
+    #[error("Package `{1}` was not found in registry {0}.")]
+    PackageNotFound(Url, String),
+
+    /// A generic request error happened while making a request. Refer to the
+    /// error message for more details.
+    #[error(transparent)]
+    RequestError(#[from] reqwest::Error),
+
+    /// A generic request middleware error happened while making a request.
+    /// Refer to the error message for more details.
+    #[error(transparent)]
+    RequestMiddlewareError(#[from] reqwest_middleware::Error),
+
+    #[error("Received some unexpected JSON. Unable to parse.")]
+    BadJson {
+        source: serde_json::Error,
+        url: String,
+    },
+}
+
+impl PypiClientError {
+    pub fn from_json_err(err: serde_json::Error, url: String) -> Self {
+        Self::BadJson {
+            source: err,
+            url: url.clone(),
+        }
+    }
+}
+
+impl PypiClient {
+    pub async fn simple(
+        &self,
+        package_name: impl AsRef<str>,
+    ) -> Result<PackageDocument, PypiClientError> {
+        // Format the URL for PyPI.
+        let mut url = self.registry.join("simple")?.join(package_name.as_ref())?;
+        url.set_query(Some("format=application/vnd.pypi.simple.v1+json"));
+
+        // Fetch from the registry.
+        let text = self.simple_impl(package_name, &url).await?;
+
+        // Parse.
+        serde_json::from_str(&text)
+            .map_err(move |e| PypiClientError::from_json_err(e, url.to_string()))
+    }
+
+    async fn simple_impl(
+        &self,
+        package_name: impl AsRef<str>,
+        url: &Url,
+    ) -> Result<String, PypiClientError> {
+        Ok(self
+            .client
+            .get(url.clone())
+            .send()
+            .await?
+            .error_for_status()
+            .map_err(|err| {
+                if err.status() == Some(StatusCode::NOT_FOUND) {
+                    PypiClientError::PackageNotFound(
+                        (*self.registry).clone(),
+                        package_name.as_ref().to_string(),
+                    )
+                } else {
+                    PypiClientError::RequestError(err)
+                }
+            })?
+            .text()
+            .await?)
+    }
+}
+
+/// The metadata for a single package, including the pubishing versions and their artifacts.
+///
+/// In npm, this is referred to as a "packument", which is a portmanteau of "package" and
+/// "document".
+#[derive(Debug, Serialize, Deserialize)]
+pub struct PackageDocument {
+    pub meta: Meta,
+    pub artifacts: Vec<ArtifactInfo>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Meta {
+    pub version: String,
+}
+
+impl Default for Meta {
+    fn default() -> Self {
+        Self {
+            // According to the spec, clients SHOULD introspect each response for the repository
+            // version; if it doesn't exist, clients MUST assume that it is version 1.0.
+            version: "1.0".into(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct ArtifactInfo {
+    pub name: String,
+    pub url: Url,
+    pub hash: Option<String>,
+    pub requires_python: Option<String>,
+    pub dist_info_metadata: DistInfoMetadata,
+    pub yanked: Yanked,
+}
+
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(from = "Option<RawDistInfoMetadata>")]
+pub struct DistInfoMetadata {
+    pub available: bool,
+    pub hash: Option<String>,
+}
+
+impl From<Option<RawDistInfoMetadata>> for DistInfoMetadata {
+    fn from(maybe_raw: Option<RawDistInfoMetadata>) -> Self {
+        match maybe_raw {
+            None => Default::default(),
+            Some(raw) => match raw {
+                RawDistInfoMetadata::NoHashes(available) => Self {
+                    available,
+                    hash: None,
+                },
+                RawDistInfoMetadata::WithHashes(_) => Self {
+                    available: true,
+                    hash: None,
+                },
+            },
+        }
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+enum RawDistInfoMetadata {
+    NoHashes(bool),
+    WithHashes(HashMap<String, String>),
+}
+
+#[derive(Debug, Clone, Deserialize)]
+enum RawYanked {
+    NoReason(bool),
+    WithReason(String),
+}
+
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(from = "RawYanked")]
+pub struct Yanked {
+    pub yanked: bool,
+    pub reason: Option<String>,
+}
+
+impl From<RawYanked> for Yanked {
+    fn from(raw: RawYanked) -> Self {
+        match raw {
+            RawYanked::NoReason(yanked) => Self {
+                yanked,
+                reason: None,
+            },
+            RawYanked::WithReason(reason) => Self {
+                yanked: true,
+                reason: Some(reason),
+            },
+        }
+    }
+}
diff --git a/crates/puffin-client/src/lib.rs b/crates/puffin-client/src/lib.rs
new file mode 100644
index 000000000..c9b3b8a54
--- /dev/null
+++ b/crates/puffin-client/src/lib.rs
@@ -0,0 +1,87 @@
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+use http_cache_reqwest::{CACacheManager, Cache, CacheMode, HttpCache, HttpCacheOptions};
+use reqwest::ClientBuilder;
+use reqwest_middleware::ClientWithMiddleware;
+use reqwest_retry::policies::ExponentialBackoff;
+use reqwest_retry::RetryTransientMiddleware;
+use url::Url;
+
+mod api;
+
+fn main() {
+    println!("Hello, world!");
+}
+
+#[derive(Debug, Clone)]
+pub struct PypiClientBuilder {
+    registry: Url,
+    retries: u32,
+    cache: Option<PathBuf>,
+}
+
+impl Default for PypiClientBuilder {
+    fn default() -> Self {
+        Self {
+            registry: Url::parse("https://pypi.org").unwrap(),
+            cache: None,
+            retries: 0,
+        }
+    }
+}
+
+impl PypiClientBuilder {
+    pub fn registry(mut self, registry: Url) -> Self {
+        self.registry = registry;
+        self
+    }
+
+    pub fn retries(mut self, retries: u32) -> Self {
+        self.retries = retries;
+        self
+    }
+
+    pub fn cache(mut self, cache: impl AsRef<Path>) -> Self {
+        self.cache = Some(PathBuf::from(cache.as_ref()));
+        self
+    }
+
+    pub fn build(self) -> PypiClient {
+        let client_raw = {
+            let mut client_core = ClientBuilder::new()
+                .user_agent("puffin")
+                .pool_max_idle_per_host(20)
+                .timeout(std::time::Duration::from_secs(60 * 5));
+
+            client_core.build().expect("Fail to build HTTP client.")
+        };
+
+        let retry_policy = ExponentialBackoff::builder().build_with_max_retries(self.retries);
+        let retry_strategy = RetryTransientMiddleware::new_with_policy(retry_policy);
+
+        let mut client_builder =
+            reqwest_middleware::ClientBuilder::new(client_raw.clone()).with(retry_strategy);
+
+        if let Some(path) = self.cache {
+            client_builder = client_builder.with(Cache(HttpCache {
+                mode: CacheMode::Default,
+                manager: CACacheManager { path },
+                options: HttpCacheOptions::default(),
+            }));
+        }
+
+        PypiClient {
+            registry: Arc::new(self.registry),
+            client: client_builder.build(),
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct PypiClient {
+    pub(crate) registry: Arc<Url>,
+    pub(crate) client: ClientWithMiddleware,
+}
+
+impl PypiClient {}
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 000000000..8f0a64ae0
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+flask==2.0