diff --git a/src/main.rs b/src/main.rs
index d9a59eb..343f409 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,18 +1,21 @@
 use std::{
+    error::Error,
     fmt::{Debug, Display},
     net::SocketAddr,
+    ops::Range,
 };
 
 use askama::Template;
 use axum::{
     extract::{Form, Path},
     http::StatusCode,
-    response::{IntoResponse, Response},
+    response::{IntoResponse, Redirect, Response},
     routing::get,
     Router,
 };
 use serde::{Deserialize, Serialize};
 use tower_sessions::{MemoryStore, Session, SessionManagerLayer};
+use unicode_segmentation::UnicodeSegmentation;
 
 #[macro_use]
 extern crate justerror;
@@ -28,13 +31,60 @@ async fn get_signup() -> impl IntoResponse {
 }
 
 /// Receives the form with the user signup fields filled out.
-async fn post_signup(session: Session, Form(form): Form<SignupForm>) -> impl IntoResponse {
-    todo!()
+async fn post_signup(
+    session: Session,
+    Form(form): Form<SignupForm>,
+) -> Result<impl IntoResponse, CreateUserError> {
+    let username = form.username.trim();
+    let password = form.password.trim();
+    let verify = form.pw_verify.trim();
+
+    let name_len = username.graphemes(true).size_hint().1.unwrap();
+    // we are not ascii exclusivists around here
+    if !(1..=20).contains(&name_len) {
+        return Err(CreateUserErrorKind::BadUsername.into());
+    }
+
+    if password != verify {
+        return Err(CreateUserErrorKind::PasswordMismatch.into());
+    }
+    let pwlen = password.graphemes(true).size_hint().1.unwrap_or(0);
+    if !(4..=50).contains(&pwlen) {
+        return Err(CreateUserErrorKind::BadPassword.into());
+    }
+
+    // clean up the optionals
+    let displayname = validate_optional_length(
+        &form.displayname,
+        0..100,
+        CreateUserErrorKind::BadDisplayname,
+    )?;
+
+    let email = validate_optional_length(&form.email, 5..30, CreateUserErrorKind::BadEmail)?;
+
+    let user = User {
+        username: username.to_string(),
+        displayname,
+        email,
+        password: password.to_string(),
+        pw_verify: verify.to_string(),
+    };
+
+    session.insert(SIGNUP_KEY, user).await.unwrap();
+
+    Ok(Redirect::to(
+        "https://buy.stripe.com/test_eVa6rrb7ygjNbwk000",
+    ))
 }
 
 /// Called from Stripe with the receipt of payment.
 async fn signup_success(session: Session, receipt: Option<Path<String>>) -> impl IntoResponse {
-    todo!()
+    let user: User = session.get(SIGNUP_KEY).await.unwrap().unwrap_or_default();
+    if user != User::default() {
+        SignupSuccessPage(user).into_response()
+    } else {
+        SignupErrorPage("who you?".to_string()).into_response()
+    }
 }
 
 #[tokio::main]
@@ -89,10 +139,27 @@ pub struct SignupForm {
     pub email: Option<String>,
     pub password: String,
     pub pw_verify: String,
-    pub invitation: String,
 }
 
-#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Debug, Default, Template, Deserialize, Serialize, PartialEq, Eq)]
+#[template(path = "signup.html")]
+pub struct SignupPage {
+    pub username: String,
+    pub displayname: Option<String>,
+    pub email: Option<String>,
+    pub password: String,
+    pub pw_verify: String,
+}
+
+#[derive(Debug, Clone, Template, Default, Deserialize, Serialize, PartialEq, Eq)]
+#[template(path = "signup_success.html")]
+pub struct SignupSuccessPage(pub User);
+
+#[derive(Debug, Clone, Template, Default, Deserialize, Serialize, PartialEq, Eq)]
+#[template(path = "signup_error.html")]
+pub struct SignupErrorPage(pub String);
+
+#[derive(Clone, PartialEq, Eq, Serialize, Deserialize, Default)]
 pub struct User {
     pub username: String,
     pub displayname: Option<String>,
@@ -145,12 +212,20 @@ where
     }
 }
 
-#[derive(Debug, Default, Template, Deserialize, Serialize, PartialEq, Eq)]
-#[template(path = "signup.html")]
-pub struct SignupPage {
-    pub username: String,
-    pub displayname: Option<String>,
-    pub email: Option<String>,
-    pub password: String,
-    pub pw_verify: String,
+pub(crate) fn validate_optional_length<E: Error>(
+    opt: &Option<String>,
+    len_range: Range<usize>,
+    err: E,
+) -> Result<Option<String>, E> {
+    if let Some(opt) = opt {
+        let opt = opt.trim();
+        let len = opt.graphemes(true).size_hint().1.unwrap();
+        if !len_range.contains(&len) {
+            Err(err)
+        } else {
+            Ok(Some(opt.to_string()))
+        }
+    } else {
+        Ok(None)
+    }
 }
diff --git a/templates/signup_success.html b/templates/signup_success.html
index 50a24a9..a95224c 100644
--- a/templates/signup_success.html
+++ b/templates/signup_success.html
@@ -7,11 +7,13 @@
 
 <h1>You did it!</h1>
 
-<div id="signup_success"><p>
-{{ self.0 }}
-</p>
+<div id="signup_success">
+    <p>
+        {{ self.0 }}
+    </p>
 </div>
-  
-<p>Now, head on over to <a href="/login">the login page</a> and get watchin'!</p>
-  
+
+<p>Now, head on over to <a href="/login?redirect_to={{ self.0.username|escape  }}">the login page</a> and get watchin'!
+</p>
+
 {% endblock %}