diff --git a/src/api/app/actions/build.rs b/src/api/app/actions/build/mod.rs
similarity index 100%
rename from src/api/app/actions/build.rs
rename to src/api/app/actions/build/mod.rs
diff --git a/src/api/app/mod.rs b/src/api/app/mod.rs
index d965e75..b938c29 100644
--- a/src/api/app/mod.rs
+++ b/src/api/app/mod.rs
@@ -1,6 +1,8 @@
 use std::sync::Arc;
 
 use anyhow::{Context, Result};
+use reqwest::Url;
+use serde::de::DeserializeOwned;
 use tokio::sync::RwLock;
 
 use super::models::{network::Network, Addon, server::Server};
@@ -16,10 +18,10 @@ pub const APP_USER_AGENT: &str = concat!(
 );
 
 pub struct App {
-    http_client: reqwest::Client,
-    server: Option<Arc<RwLock<Server>>>,
-    network: Option<Arc<RwLock<Network>>>,
-    ci: bool,
+    pub http_client: reqwest::Client,
+    pub server: Option<Arc<RwLock<Server>>>,
+    pub network: Option<Arc<RwLock<Network>>>,
+    pub ci: bool,
 }
 
 impl App {
@@ -37,6 +39,17 @@ impl App {
         })
     }
 
+    pub async fn http_get_json<T: DeserializeOwned>(&self, url: impl Into<Url>) -> Result<T> {
+        Ok(self.http_client
+            .get(url.into())
+            .send()
+            .await?
+            .error_for_status()?
+            .json()
+            .await?
+        )
+    }
+
     pub async fn collect_addons(&self) -> Result<Vec<Addon>> {
         let mut addons = vec![];
 
diff --git a/src/api/mod.rs b/src/api/mod.rs
index 1fa4cff..7b76171 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -2,3 +2,4 @@ pub mod models;
 pub mod app;
 pub mod tools;
 pub mod utils;
+pub mod sources;
diff --git a/src/api/models/addon/mod.rs b/src/api/models/addon/mod.rs
index d33db7d..0cd1e44 100644
--- a/src/api/models/addon/mod.rs
+++ b/src/api/models/addon/mod.rs
@@ -1,7 +1,5 @@
 mod addon;
-mod addon_source;
 mod addon_type;
 
 pub use addon::*;
-pub use addon_source::*;
 pub use addon_type::*;
diff --git a/src/api/models/lockfile/mod.rs b/src/api/models/lockfile/mod.rs
new file mode 100644
index 0000000..0b3fdb8
--- /dev/null
+++ b/src/api/models/lockfile/mod.rs
@@ -0,0 +1,3 @@
+pub struct Lockfile {
+
+}
diff --git a/src/api/models/mod.rs b/src/api/models/mod.rs
index 2be555e..6497d3e 100644
--- a/src/api/models/mod.rs
+++ b/src/api/models/mod.rs
@@ -1,6 +1,7 @@
 mod modpack_source;
 mod step;
 mod env;
+mod source;
 
 pub mod addon;
 pub mod packwiz;
@@ -8,8 +9,10 @@ pub mod mrpack;
 pub mod unsup;
 pub mod network;
 pub mod server;
+pub mod lockfile;
 
 pub use modpack_source::*;
 pub use step::*;
 pub use addon::*;
 pub use env::*;
+pub use source::*;
diff --git a/src/api/models/mrpack/mod.rs b/src/api/models/mrpack/mod.rs
index e69de29..482e5c3 100644
--- a/src/api/models/mrpack/mod.rs
+++ b/src/api/models/mrpack/mod.rs
@@ -0,0 +1,27 @@
+pub const MRPACK_INDEX_FILE: &str = "modrinth.index.json";
+
+mod mrpack_index;
+mod mrpack_file;
+
+use anyhow::Result;
+pub use mrpack_index::*;
+pub use mrpack_file::*;
+
+use crate::api::{app::App, utils::accessor::Accessor};
+
+use super::Addon;
+
+pub async fn resolve_mrpack_addons(
+    app: &App,
+    accessor: Accessor,
+) -> Result<Vec<Addon>> {
+    
+
+    todo!()
+}
+
+impl MRPackFile {
+    pub async fn into_addon(&self) -> Result<Addon> {
+        todo!()
+    }
+}
diff --git a/src/api/models/mrpack/mrpack_file.rs b/src/api/models/mrpack/mrpack_file.rs
new file mode 100644
index 0000000..3aaaeed
--- /dev/null
+++ b/src/api/models/mrpack/mrpack_file.rs
@@ -0,0 +1,27 @@
+use std::collections::HashMap;
+
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Deserialize, Serialize, Clone)]
+#[serde(rename_all = "camelCase")]
+pub struct MRPackFile {
+    path: String,
+    hashes: HashMap<String, String>,
+    env: Option<Env>,
+    file_size: u64,
+    downloads: Vec<String>,
+}
+
+#[derive(Debug, Deserialize, Serialize, Clone)]
+pub struct Env {
+    pub client: EnvSupport,
+    pub server: EnvSupport,
+}
+
+#[derive(Debug, Deserialize, Serialize, PartialEq, Clone)]
+#[serde(rename_all = "snake_case")]
+pub enum EnvSupport {
+    Required,
+    Optional,
+    Unsupported,
+}
diff --git a/src/api/models/mrpack/mrpack_index.rs b/src/api/models/mrpack/mrpack_index.rs
new file mode 100644
index 0000000..9611e3f
--- /dev/null
+++ b/src/api/models/mrpack/mrpack_index.rs
@@ -0,0 +1,16 @@
+use std::collections::HashMap;
+
+use serde::{Deserialize, Serialize};
+
+use super::MRPackFile;
+
+#[derive(Debug, Deserialize, Serialize, Clone)]
+#[serde(rename_all = "camelCase")]
+pub struct MRPackIndex {
+    pub game: String,
+    pub name: String,
+    pub version_id: String,
+    pub summary: Option<String>,
+    pub files: Vec<MRPackFile>,
+    pub dependencies: HashMap<String, String>,
+}
diff --git a/src/api/models/server/mod.rs b/src/api/models/server/mod.rs
index cd6091b..400f7dd 100644
--- a/src/api/models/server/mod.rs
+++ b/src/api/models/server/mod.rs
@@ -1,6 +1,6 @@
 use serde::{Serialize, Deserialize};
 
-use super::AddonSource;
+use super::Source;
 
 mod server_type;
 mod server_flavor;
@@ -14,7 +14,7 @@ pub struct Server {
     pub name: String,
     pub port: Option<i32>,
 
-    pub sources: Vec<AddonSource>,
+    pub sources: Vec<Source>,
 }
 
 impl Default for Server {
diff --git a/src/api/models/addon/addon_source.rs b/src/api/models/source.rs
similarity index 70%
rename from src/api/models/addon/addon_source.rs
rename to src/api/models/source.rs
index 3ad4658..df122d3 100644
--- a/src/api/models/addon/addon_source.rs
+++ b/src/api/models/source.rs
@@ -5,7 +5,8 @@ use crate::api::{app::App, models::ModpackSource};
 use super::Addon;
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
-pub enum AddonSource {
+#[serde(tag = "type", rename_all = "lowercase")]
+pub enum Source {
     File {
         path: String,
     },
@@ -15,22 +16,23 @@ pub enum AddonSource {
     },
 
     Modpack {
+        #[serde(flatten)]
         modpack: ModpackSource,
     },
 }
 
-impl AddonSource {
+impl Source {
     pub async fn resolve(&self, app: &App) -> Result<Vec<Addon>> {
         match self {
-            AddonSource::File { path } => {
+            Source::File { path } => {
                 Ok(vec![])
             }
 
-            AddonSource::Folder { path } => {
+            Source::Folder { path } => {
                 Ok(vec![])
             }
 
-            AddonSource::Modpack { modpack } => {
+            Source::Modpack { modpack } => {
                 Ok(vec![])
             }
         }
diff --git a/src/api/models/step.rs b/src/api/models/step.rs
index e99edca..bc39740 100644
--- a/src/api/models/step.rs
+++ b/src/api/models/step.rs
@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use std::{borrow::Cow, collections::HashMap};
 
 use anyhow::Result;
 use serde::{Deserialize, Serialize};
@@ -18,20 +18,18 @@ pub enum Step {
     Execute,
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(tag = "type")]
 pub enum CacheStrategy {
     File {
-        namespace: String,
+        namespace: Cow<'static, str>,
         path: String,
     },
     Indexed {
-        index_path: String,
+        namespace: Cow<'static, str>,
+        path: Option<String>,
         key: String,
-        value: String,
     },
-    #[default]
-    None,
 }
 
 pub enum StepResult {
diff --git a/src/api/sources/mod.rs b/src/api/sources/mod.rs
index e69de29..a491ad1 100644
--- a/src/api/sources/mod.rs
+++ b/src/api/sources/mod.rs
@@ -0,0 +1,33 @@
+use std::collections::HashMap;
+
+use anyhow::Result;
+
+use super::{app::App, models::{CacheStrategy, Step}, utils::url::get_filename_from_url};
+
+pub mod vanilla;
+
+pub async fn resolve_steps_for_url(
+    app: &App,
+    url: impl Into<String>,
+    filename: Option<String>,
+) -> Result<Vec<Step>> {
+    let url: String = url.into();
+
+    let filename = filename.unwrap_or_else(|| {
+        get_filename_from_url(&url)
+    });
+
+    Ok(vec![
+        Step::CacheCheck(CacheStrategy::Indexed {
+            namespace: "url".into(),
+            path: None,
+            key: url.clone(),
+        }),
+        Step::Download {
+            url: url.into(),
+            filename,
+            size: None,
+            hashes: HashMap::new(),
+        }
+    ])
+}
diff --git a/src/api/sources/vanilla/mod.rs b/src/api/sources/vanilla/mod.rs
new file mode 100644
index 0000000..00d45cb
--- /dev/null
+++ b/src/api/sources/vanilla/mod.rs
@@ -0,0 +1,7 @@
+use crate::api::app::App;
+
+pub struct VanillaAPI<'a>(pub &'a App);
+
+impl<'a> VanillaAPI<'a> {
+    
+}
diff --git a/src/api/utils/accessor.rs b/src/api/utils/accessor.rs
index 2315fcb..487d8ff 100644
--- a/src/api/utils/accessor.rs
+++ b/src/api/utils/accessor.rs
@@ -1,10 +1,36 @@
-use std::path::PathBuf;
+use std::{ffi::OsString, fs::DirEntry, io::{Read, Seek}, path::PathBuf};
+
+use anyhow::{anyhow, Result};
+use serde::de::DeserializeOwned;
+use zip::ZipArchive;
+
+use crate::api::app::App;
+
+pub trait ReadSeek: std::io::Read + Seek {}
 
 pub enum Accessor {
     Local(PathBuf),
     Remote(reqwest::Url),
+    Zip(ZipArchive<Box<dyn ReadSeek>>),
 }
 
 impl Accessor {
-    
+    pub async fn dir(&self) -> Result<Vec<String>> {
+        match self {
+            Accessor::Zip(zip) => Ok(zip.file_names().map(ToOwned::to_owned).collect()),
+            Accessor::Local(path) => Ok(path.read_dir()?
+                .filter_map(|r| r.ok())
+                .map(|n| n.file_name().to_string_lossy().into_owned())
+                .collect()),
+            Accessor::Remote(_) => Err(anyhow!("cannot dir() Accessor::Remote")),
+        }
+    }
+
+    pub async fn json<T: DeserializeOwned>(&mut self, app: &App, path: &str) -> Result<T> {
+        match self {
+            Accessor::Local(base) => Ok(serde_json::from_reader(std::fs::File::open(base.join(path))?)?),
+            Accessor::Zip(zip) => Ok(serde_json::from_reader(zip.by_name(path)?)?),
+            Accessor::Remote(url) => Ok(app.http_get_json(url.join(path)?).await?),
+        }
+    }
 }
diff --git a/src/api/utils/mod.rs b/src/api/utils/mod.rs
index 13ff7f6..7934fba 100644
--- a/src/api/utils/mod.rs
+++ b/src/api/utils/mod.rs
@@ -1,3 +1,4 @@
 pub mod hashing;
 pub mod accessor;
 pub mod serde;
+pub mod url;
diff --git a/src/api/utils/url.rs b/src/api/utils/url.rs
new file mode 100644
index 0000000..e515091
--- /dev/null
+++ b/src/api/utils/url.rs
@@ -0,0 +1,4 @@
+pub fn get_filename_from_url(url: &str) -> String {
+    let url_clean = url.split(&['?', '#'][..]).next().unwrap();
+    url_clean.split('/').last().unwrap().to_string()
+}
diff --git a/src/commands/build.rs b/src/commands/build.rs
new file mode 100644
index 0000000..e69de29
diff --git a/src/commands/mod.rs b/src/commands/mod.rs
index 43763f1..d07ba46 100644
--- a/src/commands/mod.rs
+++ b/src/commands/mod.rs
@@ -1 +1,2 @@
 pub mod init;
+pub mod build;