diff --git a/.docker/docker-compose.yml b/.docker/docker-compose.yml
index 0812ef743..4d7ab08b5 100644
--- a/.docker/docker-compose.yml
+++ b/.docker/docker-compose.yml
@@ -10,6 +10,7 @@ services:
       - POSTGRES_HOST=amplify_db
     ports:
       - 8080:8080
+      - 5000:5000
     volumes:
       - type: bind
         source: '../'
diff --git a/.env b/.env
index 193e5c6d6..7a551280e 100644
--- a/.env
+++ b/.env
@@ -1,5 +1,5 @@
 ###########################
-#   Example `.env` file   #
+#  Environment Variables  #
 ###########################
 
 # API key for the Cicero API
@@ -8,7 +8,11 @@ CICERO_API_KEY=
 
 # Test environment API key for the Lob API
 # This is only required for running the integration tests successfully!
-LOB_API_KEY="test_eee78731c29fe718a5322e0cd51e9a02f0e"
+LOB_API_KEY=test_eee78731c29fe718a5322e0cd51e9a02f0e
+LOB_BASE_URL=https://api.lob.com/v1
+
+# Sendgrid
+SENDGRID_API_KEY=
 
 # Auth0 authentication parameters
 # For local development, you can just use these literal nonsense values for now
@@ -25,19 +29,12 @@ TWILIO_ACCOUNT_SID=your_twilio_account_id # this is user generated
 TWILIO_AUTH_TOKEN=TWILIO_SECRET_KEY
 
 # To run in single-campaign mode, set the following environment vars
+# **We always run in single-campaign mode now so this is mandatory!**
+# Use campaign seeder file for local dev campaigns.
 VUE_APP_CAMPAIGN_MODE=single
 VUE_APP_FEATURED_CAMPAIGN=1
-VUE_APP_LETTER_TEMPLATE=tmpl_951e09eb07bfd24
 
 POSTGRES_USER=postgres
 POSTGRES_PASSWORD=postgres
 POSTGRES_PORT=5432
 POSTGRES_HOST=amplify_db
-
-# Enable $0 transactions (set to 'on' to enable, used in both FE and BE)
-# If EMPTY_TRANSACTIONS=on then NO_COST_MAIL should = true
-VUE_APP_EMPTY_TRANSACTIONS=on
-VUE_APP_NO_COST_MAIL=true
-VUE_APP_COUPON_CODE=
-VUE_APP_SHOW_EXT_DONATION=false
-VUE_APP_EXT_DONATION_URL="https://greenaction.org"
\ No newline at end of file
diff --git a/server/db/migrations/20241013134620_add_tracking_to_letters.js b/server/db/migrations/20241013134620_add_tracking_to_letters.js
new file mode 100644
index 000000000..15b478f8b
--- /dev/null
+++ b/server/db/migrations/20241013134620_add_tracking_to_letters.js
@@ -0,0 +1,13 @@
+module.exports = {
+  async up(knex) {
+    await knex.schema.alterTable('letters', (table) => {
+      table.uuid('tracking_number')
+    })
+  },
+
+  async down(knex) {
+    await knex.schema.alterTable('letters', (table) => {
+      table.dropColumn('tracking_number')
+    })
+  }
+}
diff --git a/server/routes/api/checkout.js b/server/routes/api/checkout.js
index 8abe83aaa..a9864db9d 100644
--- a/server/routes/api/checkout.js
+++ b/server/routes/api/checkout.js
@@ -1,4 +1,5 @@
 const express = require('express')
+const axios = require('axios')
 const { v4: uuidv4 } = require('uuid')
 const { Stripe, StripeError } = require('../../lib/stripe')
 const {
@@ -108,6 +109,7 @@ router.post('/create-checkout-session', async (req, res) => {
       .json({ url: session.url, sessionId: session.id })
       .end()
   } catch (error) {
+    console.error(error)
     let statusCode = 500
 
     if (error instanceof PaymentPresenterError) {
@@ -123,11 +125,12 @@ router.post('/create-checkout-session', async (req, res) => {
 
 router.post('/process-transaction', async (req, res) => {
   try {
-    const stripe = new Stripe()
+    // const stripe = new Stripe()
 
     // If livemode is false, disable signature checking
     // and event reconstructionfor ease of testing.
     let event
+    /*
     if (stripe.livemode) {
       const signature = req.headers['stripe-signature']
       if (!signature) throw new CheckoutError('No stripe signature on request!')
@@ -135,13 +138,19 @@ router.post('/process-transaction', async (req, res) => {
       event = stripe.validateEvent(signature, req.rawBody)
     } else {
       event = req.body
-      console.log(event)
+      // console.log(event)
     }
+    */
+    event = req.body
+
+    if (!event) throw new CheckoutError('Unprocessable message')
 
     const data = event.data
     const { id: paymentIntent, amount } = data.object
     const [eventType, eventOutcome] = req.body.type.split('.')
 
+    console.log(paymentIntent, amount, eventOutcome)
+
     // We are not going to send letters from here just yet
     // so we will record the transaction no matter the outcome.
     if (eventType !== 'payment_intent') {
@@ -150,12 +159,53 @@ router.post('/process-transaction', async (req, res) => {
       )
     }
 
-    await Transaction.query()
-      .patch({ amount, status: eventOutcome })
-      .where({ stripe_transaction_id: paymentIntent })
+    const transaction = await Transaction.query().findOne({ stripe_transaction_id: paymentIntent })
+    await transaction.$query().patch({ status: eventOutcome })
+
+    console.log(`transaction = ${transaction.id}, ${transaction.status}`)
+
+    const letter = await Letter.query().where({ transaction_id: transaction.id }).first()
+    letter.trackingNumber = uuidv4()
+    const letterTemplate = JSON.parse(letter.letterTemplate)
+    
+    console.log(`letter: ${letter.id}, ${letterTemplate}`)
+    
+    const lobApiKey = process.env.LOB_API_KEY
+    const lobCredentials = btoa(`${lobApiKey}:`)
+
+    console.log(letter.addressee, letter.addressLine1)
+    const lobResponse = await axios.post(
+      'https://api.lob.com/v1/letters', 
+      {
+        to: {
+          name: letter.addressee,
+          address_line1: letter.addressLine1,
+          address_line2: letter.addressLine2,
+          address_city: letter.city,
+          address_state: letter.state,
+          address_zip: letter.zip
+        },
+        from: letter.returnAddress,
+        color: false,
+        use_type: 'operational',
+        file: letterTemplate.latest_template_preview.template_id,
+        merge_variables: letter.mergeVariables
+      },
+      {
+        headers: {
+          Authorization: `Basic ${lobCredentials}`,
+          'Idempotency-Key': letter.trackingNumber
+        }
+      }
+    )
+
+    if (!lobResponse.statusCode === 200) throw new CheckoutError(lobResponse)
+
+    await letter.$query().patch({ sent: true})
 
-    return res.status(200).end()
+    return res.status(201).end()
   } catch (error) {
+    console.error(error.response.data.error)
     let statusCode = 500
 
     if (error instanceof CheckoutError) {