diff --git a/.vscode/settings.json b/.vscode/settings.json
index 2c63c085..0967ef42 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,2 +1 @@
-{
-}
+{}
diff --git a/lib/bn.js b/lib/bn.js
new file mode 100644
index 00000000..a9016d39
--- /dev/null
+++ b/lib/bn.js
@@ -0,0 +1,6 @@
+const BigNumber = require('bignumber.js')
+
+BigNumber.config({ROUNDING_MODE: BigNumber.ROUND_HALF_EVEN})
+
+function BN (s) { return new BigNumber(s) }
+module.exports = BN
diff --git a/lib/cash-in-tx.js b/lib/cash-in-tx.js
new file mode 100644
index 00000000..689d0987
--- /dev/null
+++ b/lib/cash-in-tx.js
@@ -0,0 +1,86 @@
+const _ = require('lodash/fp')
+const pgp = require('pg-promise')()
+const db = require('./db')
+const BN = require('./bn')
+
+module.exports = {postCashIn}
+
+const UPDATEABLE_FIELDS = ['fee', 'txHash', 'phone', 'error']
+
+function postCashIn (tx, pi) {
+  const TransactionMode = pgp.txMode.TransactionMode
+  const isolationLevel = pgp.txMode.isolationLevel
+  const tmSRD = new TransactionMode({tiLevel: isolationLevel.serializable})
+
+  function transaction (t) {
+    const sql = 'select * from cash_in_txs where id=$1'
+    return t.oneOrNone(sql, [tx.id])
+    .then(row => upsert(row, tx))
+  }
+
+  transaction.txMode = tmSRD
+
+  return db.tx(transaction)
+  .then(txVector => postProcess(txVector, pi))
+  .then(changes => update(tx.id, changes))
+}
+
+function diff (oldTx, newTx) {
+  let updatedTx = {}
+
+  UPDATEABLE_FIELDS.forEach(fieldKey => {
+    if (_.isEqual(oldTx[fieldKey], newTx[fieldKey])) return
+    updatedTx[fieldKey] = newTx[fieldKey]
+  })
+
+  return updatedTx
+}
+
+function toObj (row) {
+  const keys = _.keys(row)
+  let newObj = {}
+
+  keys.forEach(key => {
+    const objKey = _.camelCase(key)
+    if (key === 'crypto_atoms' || key === 'fiat') {
+      newObj[objKey] = BN(row[key])
+      return
+    }
+
+    newObj[objKey] = row[key]
+  })
+
+  return newObj
+}
+
+function upsert (row, tx) {
+  const oldTx = toObj(row)
+
+  if (oldTx) return insert(tx)
+  return update(tx.id, diff(oldTx, tx))
+}
+
+function insert (tx) {
+  const dbTx = _.mapKeys(_.snakeCase, tx)
+
+  const sql = pgp.helpers.insert(dbTx, null, 'cash_in_txs')
+  return db.none(sql)
+}
+
+function update (txId, changes) {
+  const dbChanges = _.mapKeys(_.snakeCase, changes)
+  const sql = pgp.helpers.update(dbChanges, null, 'cash_in_txs') +
+    pgp.as.format(' where id=$1', [txId])
+
+  return db.none(sql)
+}
+
+function postProcess (txVector, pi) {
+  const [oldTx, newTx] = txVector
+
+  if (newTx.sent && !oldTx.sent) {
+    return pi.sendCoins(newTx)
+    .then(txHash => ({txHash}))
+    .catch(error => ({error}))
+  }
+}
diff --git a/lib/plugins.js b/lib/plugins.js
index 6572d748..736e4c14 100644
--- a/lib/plugins.js
+++ b/lib/plugins.js
@@ -133,8 +133,8 @@ function plugins (settings) {
   }
 
   // NOTE: This will fail if we have already sent coins because there will be
-  // a dbm unique dbm record in the table already.
-  function executeTx (deviceId, tx) {
+  // a unique dbm record in the table already.
+  function sendCoins (deviceId, tx) {
     return dbm.addOutgoingTx(deviceId, tx)
     .then(() => wallet.sendCoins(settings, tx.toAddress, tx.cryptoAtoms, tx.cryptoCode))
     .then(txHash => {
@@ -185,10 +185,6 @@ function plugins (settings) {
     return dbm.machineEvent(event)
   }
 
-  function sendCoins (deviceId, rawTx) {
-    return executeTx(deviceId, rawTx)
-  }
-
   function cashOut (deviceId, tx) {
     const cryptoCode = tx.cryptoCode
 
diff --git a/lib/routes.js b/lib/routes.js
index 5d93604d..e0fbf18a 100644
--- a/lib/routes.js
+++ b/lib/routes.js
@@ -374,6 +374,7 @@ app.post('/verify_user', verifyUser)
 app.post('/verify_transaction', verifyTx)
 
 app.post('/phone_code', phoneCode)
+app.post('/tx', postTx)
 
 app.use(errorHandler)
 app.use((req, res) => res.status(404).json({err: 'No such route'}))
diff --git a/lib/tx.js b/lib/tx.js
index 521bc9a3..dd1283a2 100644
--- a/lib/tx.js
+++ b/lib/tx.js
@@ -8,12 +8,12 @@ function postCashIn (tx) {
 
   function transaction (t) {
     const sql = 'select * from cash_in_txs where id=$1'
-    return t.one(sql, [tx.id])
+    return t.oneOrNone(sql, [tx.id])
     .then(row => {
-      const newTx = executeTxChange(tx, row)
+      const newTx = executeCashInTxChange(tx, row)
 
-      if (row) return updateCashOutTx(newTx)
-      insertCashOutTx(newTx)
+      if (row) return updateCashInTx(newTx)
+      insertCashInTx(newTx)
     })
   }
 
@@ -24,13 +24,14 @@ function postCashIn (tx) {
 }
 
 function postCashOut (tx) {
-
+  throw new Error('not implemented')
 }
 
 function post (tx) {
   if (tx.direction === 'cashIn') return postCashIn(tx)
   if (tx.direction === 'cashOut') return postCashOut(tx)
-  throw new Error('No such tx direction: %s', tx.direction)
+
+  return Promise.reject(new Error('No such tx direction: %s', tx.direction))
 }
 
 module.exports = {post}
diff --git a/migrations/022-add_cash_in_sent.js b/migrations/022-add_cash_in_sent.js
new file mode 100644
index 00000000..c3b1c982
--- /dev/null
+++ b/migrations/022-add_cash_in_sent.js
@@ -0,0 +1,12 @@
+var db = require('./db')
+
+exports.up = function (next) {
+  var sql = [
+    'alter table cash_in_txs add column sent boolean not null default false'
+  ]
+  db.multi(sql, next)
+}
+
+exports.down = function (next) {
+  next()
+}