# Classify Your Own Transactions
When your application already has access to users' transaction data, Sail can help identify which transactions qualify as tax-deductible healthcare expenses under [IRS Section 213(d)](https://www.irs.gov/publications/p502).
In this guide, you'll create an external connection, push a batch of transactions, and read back the classification results.
## Requirements
Before you start, make sure you have:
- A [Sail user](/docs/get-started/get-started-overview/create-a-user) created for your internal user
- An [API key](/docs/get-started/get-started-overview/api-key) with the `expenses` and `ingest` scopes
- A [webhook endpoint](/docs/get-started/get-started-overview/webhooks) configured to receive events
## Step 1: Create an external connection
Before you can push transactions, you need to [Create an External Connection](/reference/connections/post-users-user-id-connections) to group the transaction data and label its source. Set `type` to `external` and choose a `provider_label` that identifies where this data comes from (for example, "Plaid feed" or "Internal ledger").
```bash
curl -X POST https://live.savewithsail.com/api/v1/users/usr_abc123/connections \
-H "Authorization: Bearer sk_live_..." \
-H "Content-Type: application/json" \
-d '{
"type": "external",
"provider_label": "Acme Budgeting ยท Plaid feed"
}'
```
```json
{
"id": "conn_9f2c",
"user_id": "usr_abc123",
"type": "external",
"status": "active",
"products": ["expenses"],
"accounts": [],
"created_at": "2026-08-10T14:32:00Z"
}
```
The response confirms the connection was created. Save the `id` (`conn_9f2c` in this example). You need it to push transactions in the next step. The `products` array shows that this connection supports `expenses`, which means Sail will classify the transactions you push to it.
## Step 2: Push transactions
Send a batch of transactions to the external connection. Sail accepts up to 500 transactions per request. Each transaction needs an `external_transaction_id` that's unique within this connection. If you push the same `external_transaction_id` again, Sail updates the existing record and re-classifies it.
```bash
curl -X POST https://live.savewithsail.com/api/v1/users/usr_abc123/connections/conn_9f2c/transactions \
-H "Authorization: Bearer sk_live_..." \
-H "Content-Type: application/json" \
-d '{
"transactions": [
{
"external_transaction_id": "tx-1001",
"date": "2026-08-05",
"amount": 27.02,
"description": "WALGREENS #4821 RX",
"merchant_name": "Walgreens",
"mcc": "5912"
},
{
"external_transaction_id": "tx-1002",
"date": "2026-08-06",
"amount": 85.00,
"description": "AMAZON.COM*AB1CD2EF3",
"merchant_name": "Amazon",
"mcc": null
}
]
}'
```
```json
{
"status": "processing",
"job_id": "job_x",
"accepted": 2,
"duplicates_updated": 0
}
```
The response returns `202` with a `job_id`. Classification happens asynchronously. Don't poll for results. Instead, listen for the `transactions.ingested` webhook.
### Listen for the webhook
After you push a batch, Sail enriches and classifies each transaction. When the batch is done, Sail sends a `transactions.ingested` webhook:
```json
{
"id": "evt_7f3k9m",
"event": "transactions.ingested",
"created_at": "2026-08-10T14:33:15Z",
"user_id": "usr_abc123",
"data": {
"connection_id": "conn_9f2c",
"job_id": "job_x",
"created": 2,
"updated": 0
}
}
```
The `created` and `updated` counts show how many expenses were new versus re-classified from a duplicate push.
You will receive an `expenses.verified` event when 213d classification has finished for these expenses.
## Step 3: Pull classification results
Once you receive the webhook, [fetch the expenses](/reference/expenses/get-users-user-id-expenses) to see how Sail classified each transaction.
```bash
curl https://live.savewithsail.com/api/v1/users/usr_abc123/expenses \
-H "Authorization: Bearer sk_live_..."
```
```json
{
"data": [
{
"id": "exp_9f2c",
"connection_id": "conn_9f2c",
"external_transaction_id": "tx-1001",
"name": "Walgreens",
"amount": 27.02,
"status": "eligible",
"source_type": "external",
"origin": {
"type": "transaction",
"detail": "WALGREENS #4821 RX"
},
"merchant": {
"name": "Walgreens",
"supported_merchant_id": "mer_walgreens"
},
"enrichment": {
"category": "Pharmacies",
"subcategory": "Drug Stores"
},
"section_213d_classification": {
"status": "eligible",
"category": "Prescription Medications",
"reasoning": "Pharmacy purchase classified as eligible under Section 213(d)."
}
}
// ... additional expenses
],
"pagination": {
"limit": 25,
"offset": 0,
"total": 2
}
}
```
You can [filter the results](/reference/expenses/get-users-user-id-expenses) by status, connection, or source type to get specific subsets:
```bash
# Get only eligible expenses
curl "https://live.savewithsail.com/api/v1/users/usr_abc123/expenses?status=eligible" \
-H "Authorization: Bearer sk_live_..."
# Get only expenses from a specific connection
curl "https://live.savewithsail.com/api/v1/users/usr_abc123/expenses?connection_id=conn_9f2c" \
-H "Authorization: Bearer sk_live_..."
```
The `section_213d_classification.status` field tells you the outcome for each transaction:
| Status | What it means | What to do |
| :--------------------- | :-------------------------------------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `eligible` | The expense qualifies as tax-deductible under Section 213(d). | No action needed. |
| `ineligible` | The expense does not qualify. | No action needed. |
| `itemization_required` | Sail can't classify the transaction without seeing individual items (for example, a mixed-basket Amazon order). | Prompt the user to connect the merchant via a [connect widget session](/reference/connect-account-widgets/post-hosted-sessions) for item-level data, or upload a receipt via the [receipt upload](/reference/expenses/post-users-user-id-expenses-expense-id-receipt) endpoint. |
| `lmn_required` | The item could be eligible with a Letter of Medical Necessity (for example, a massage chair). | Prompt the user to provide a letter from their healthcare provider. |
The top-level `status` field groups these into three categories: `eligible`, `ineligible`, and `needs_review` (which covers both `itemization_required` and `lmn_required`).
**Note**
Check the `merchant.supported_merchant_id` field in the expense response. When it is non-null for a `needs_review` expense, Sail supports a store connection for that merchant. Prompt the user to connect their merchant account through the Connect widget to retrieve item-level data and classify individual items. See [Enrich transactions with item-level data](/docs/guides/enrich-transactions-with-item-level-data) for details.