# EDI 824 Application Advice: Complete Guide

> How the EDI 824 Application Advice transaction works. Learn error reporting, segment structure, and how to use 824s for EDI troubleshooting.

**The EDI 824 Application Advice is the X12 transaction set that trading partners use to report business-level errors in a document they already acknowledged as syntactically valid.** It is the document that arrives after you get a clean 997 and tells you the invoice PO number does not exist, the price does not match, or the item is not in their catalog.

## What is an EDI 824?

**An EDI 824 Application Advice is a structured error notification defined by the [ASC X12 standards body](https://x12.org/) that a trading partner sends when the content of a received document fails application-level validation, even after the 997 syntax check passed.**

Authoritative sources for 824 implementation:

- The [X12.org Transaction Sets reference](https://x12.org/products/transaction-sets) defines the OTI, TED, and NTE segment structure used in all 824 implementations
- Retailer-specific 824 error code lists are published in their vendor implementation guides (Walmart SupplierOne, Target Partners Online, Amazon Vendor Central)

An 824 is sent by a trading partner (usually a retailer or buyer) when they find problems with the content of your EDI document, even though the syntax was valid.

**The key difference from a 997:**

| | 997 Functional Acknowledgment | 824 Application Advice |
|---|---|---|
| **Checks** | Syntax and structure | Business content and data |
| **Timing** | Sent immediately on receipt | Sent after processing |
| **Example error** | "Missing required N1 segment" | "Invalid PO number - not found in our system" |
| **Scope** | Envelope and segment validation | Application-level validation |

A document can pass the 997 check (valid syntax) but still fail the 824 check (bad business data). You might send a perfectly formatted 810 Invoice, get an accepted 997, and then receive an 824 saying the invoice references a PO number that does not exist.

## When Do Retailers Send 824s?

Retailers and buyers send 824s when they process your EDI documents and find data problems:

- **Invalid PO numbers** - Your 810 Invoice references an order they cannot find
- **Duplicate submissions** - You sent the same 856 ASN twice
- **Price mismatches** - Your invoice price does not match the agreed contract price
- **Invalid item numbers** - UPC or SKU does not exist in their system
- **Quantity issues** - Invoiced quantity exceeds the ordered or received quantity
- **Missing required data** - A field the retailer needs is present but empty or wrong

These are all problems a 997 would never catch because the EDI file itself is structurally valid.

## Key Segments Explained

### OTI - Original Transaction Identification

The OTI segment identifies which original transaction the 824 is reporting on:

```
OTI*TR*IA*000001234*VENDOR123*BUYER456*20260301*IN*810*0001
```

- **OTI01**: Application Acknowledgment Code
  - TR = Transaction Accepted with Errors
  - TA = Transaction Accepted (no errors)
  - TN = Transaction Not Accepted (rejected)
  - TE = Transaction Accepted, Content Not Accepted
- **OTI02**: Reference Identification Qualifier (IA = Internal Vendor Number)
- **OTI03**: Reference Identification (original control number or PO number)
- **OTI04**: Application Sender's Code
- **OTI05**: Application Receiver's Code
- **OTI06**: Date
- **OTI07**: Functional Identifier Code (IN = Invoice)
- **OTI08**: Transaction Set Identifier Code (810)
- **OTI09**: Transaction Set Control Number

### TED - Technical Error Description

The TED segment carries the actual error detail:

```
TED*020*Invalid purchase order number referenced on invoice
```

- **TED01**: Application Error Condition Code
- **TED02**: Free-form text describing the error

**Common TED01 Error Codes:**

| Code | Meaning |
|------|---------|
| 001 | Unrecognized interchange sender ID |
| 002 | Unrecognized interchange receiver ID |
| 009 | Unknown transaction set |
| 015 | Duplicate control number |
| 018 | Invalid date |
| 019 | Invalid time |
| 020 | Invalid data value |
| 023 | Data element missing |
| 024 | Duplicate data |
| 025 | Invalid characters |
| 028 | Invalid price |

### NTE - Note/Special Instruction

The NTE segment provides additional context about the error:

```
NTE*ERR*PO number 4500012345 not found in system. Verify PO was transmitted and accepted.
```

- **NTE01**: Note Reference Code (ERR = Error description)
- **NTE02**: Free-form message text

The NTE segment is where you often find the most useful troubleshooting information. Retailers will spell out exactly what they expected vs. what they received.

## Real-World 824 Example

Here is a complete 824 rejecting an 810 Invoice due to an invalid PO number:

```
ISA*00*          *00*          *ZZ*BUYER456       *ZZ*VENDOR123      *260305*0930*U*00401*000000042*0*P*:~
GS*AG*BUYER456*VENDOR123*20260305*0930*42*X*004010~
ST*824*0042~
OTI*TN*IA*000001234*VENDOR123*BUYER456*20260301*IN*810*0001~
TED*020*Purchase order number 4500012345 not found~
NTE*ERR*The PO number on your invoice does not match any active order. Check for typos or confirm the PO was transmitted.~
SE*5*0042~
GE*1*42~
IEA*1*000000042~
```

**Translation**: "We rejected your 810 Invoice (control #0001, sent March 1) because PO number 4500012345 does not exist in our system."

## How to Troubleshoot 824 Errors

When you receive an 824, follow this process:

1. **Read the OTI segment** to identify which original transaction is affected
2. **Check the TED code** to understand the error category
3. **Read the NTE text** for specific detail on what went wrong
4. **Pull up the original transaction** and compare it against the error
5. **Fix the data** in your source system (ERP, WMS, etc.)
6. **Resubmit the corrected transaction**

Use the [EDI Inspector](/edi-inspector) to parse and validate your original transaction side-by-side with the 824 to pinpoint the problem fast.

## 824 vs. 997: Which One Should You Expect?

Here is a typical flow showing how both work together:

```
1. You send 810 Invoice
2. Partner sends 997*A       (syntax is valid - good)
3. Partner processes invoice
4. Partner sends 824*TN      (business data rejected - problem)
```

The 997 and 824 are not mutually exclusive. You will often receive both: first the 997 confirming receipt, then the 824 reporting content issues found during processing.

**When you only get a 997 rejection (no 824):**
The problem is structural. Your file could not even be parsed. Fix the EDI syntax first.

**When you get 997*A followed by an 824:**
Your syntax is fine, but the data inside is wrong. Fix the business content (PO numbers, prices, quantities, item codes).

## Common 824 Scenarios

### Scenario 1: Duplicate Invoice

```
OTI*TN*IA*000001234~~~IN*810*0001~
TED*024*Duplicate invoice number INV-2026-0042~
NTE*ERR*This invoice number was already submitted and processed on 2026-02-28.~
```

**Fix**: Check your invoice numbering. Resending the same invoice number triggers a duplicate rejection.

### Scenario 2: Price Mismatch

```
OTI*TR*IA*000001234~~~IN*810*0002~
TED*028*Unit price does not match purchase order~
NTE*ERR*Line 3: Invoice price $14.99, PO price $12.99 for item UPC 012345678901.~
```

**Fix**: Compare your invoice prices against the original [850 Purchase Order](/guides/edi/850-purchase-order). Update your price file if the contract changed.

### Scenario 3: Invalid Item

```
OTI*TN*IA*000001234~~~SH*856*0003~
TED*020*Unrecognized item identifier~
NTE*ERR*UPC 999999999999 on line 5 is not set up in buyer item master.~
```

**Fix**: Confirm the UPC or SKU is active in the retailer's system. You may need to complete item setup before shipping.

## Best Practices

### 1. Monitor 824s daily

Do not let 824s pile up. Each one represents a transaction your trading partner could not process. Unresolved 824s lead to payment delays and compliance issues.

### 2. Build a response workflow

Assign 824 errors to the right team:
- **Invalid PO/item** errors go to order management
- **Price mismatch** errors go to pricing or contracts
- **Duplicate** errors go to your EDI team to check transmission logs

### 3. Track error patterns

If you keep getting the same TED code from the same partner, there is a systemic issue. Fix the root cause in your ERP or mapping configuration instead of correcting each transaction one at a time.

### 4. Use the EDI Inspector

Paste your 824 into the [EDI Inspector](/edi-inspector) to quickly identify the referenced transaction and error codes. Cross-reference with your [EDI compliance checklist](/blog/edi-compliance) to prevent recurring issues.

## FAQ

### How quickly should I respond to an 824?

There is no universal SLA for 824 responses, but you should fix and resubmit the corrected transaction within 24-48 hours. Delays can hold up payments (for invoices) or cause order fulfillment problems. Check your trading partner agreement for specific timelines.

### Can I send an 824 back to my trading partner?

Yes. The 824 is bidirectional. If you receive an EDI document from a partner and the business content has errors, you can send an 824 back to report those issues. This is common when receiving inbound [856 Ship Notices](/guides/edi/856-ship-notice) or 850 Purchase Orders with data problems.

### Do I need to send a 997 for an 824 I receive?

Yes. The 824 is itself an EDI transaction, so your system should send a [997 Functional Acknowledgment](/guides/edi/997-functional-acknowledgment) confirming you received the 824. This follows the same rules as any other inbound transaction. For a full walkthrough on setting up your acknowledgment process, see the [EDI implementation guide](/blog/essential-guide-to-edi).

## Related Transaction Sets

- **[997 Functional Acknowledgment](/guides/edi/997-functional-acknowledgment)** - Syntax-level acknowledgment (pair with 824 for full coverage)
- **[850 Purchase Order](/guides/edi/850-purchase-order)** - Common source transaction referenced in 824 errors
- **[810 Invoice](/guides/edi/810-invoice)** - Frequently triggers 824s for price and PO mismatches

## Need Help?

Try the [EDI Inspector](/edi-inspector) to parse your 824 Application Advice documents, or review the [EDI compliance checklist](/blog/edi-compliance) to prevent common errors before they happen.