From error codes to actions

Understand payment declines. Take the right action.

Decline Decoder helps merchants and payments teams understand why a payment failed, whether to retry, what to tell the customer, and how to prevent similar failures.

Example diagnosis

04
NACH
Recurring
1st attempt
Car loan EMI · ₹7,500
Same code, opposite answer: on a card, 04 means 'pick up card' and must never be retried. On NACH, it means the account didn't have enough balance.

Why it failed

Insufficient funds. The customer's account was short on the debit date.

What to do

Re-present the EMI a few days after the customer's likely salary date, and remind them two days before.

Retry?

Yes — In the next NACH presentation cycle, timed after salary credit rather than straight away.

Prevent it

Move the EMI date close to when the customer is paid.

Customer message

Your EMI payment of ₹7,500 didn't go through this time. We'll try again on [date], so please keep the amount available in your account.

What can you do with Decline Decoder?

Turn payment failures into actionable insights.

Understand the root cause

Decode cryptic error codes across cards, UPI, UPI Autopay and NACH into plain English.

Know whether to retry

Retry advice with timing, based on NPCI, RBI and card-network rules.

Get the right customer message

Ready-to-send messages that never guess or blame the customer.

Find patterns and prevent failures

Spot repeated problems in a batch, like expiring mandates, and fix them at the source.

How it works

From one decline to a clear next step.

1

Payment details

The decline code, payment method, amount, mandate type and attempt number, plus anything the bank or customer said.

2

Check the reference

The code is looked up in a reference of 200 codes grouped into 18 root causes. If it isn't there, the tool says so instead of guessing.

3

AI diagnosis

For known codes, AI picks the right cause from the reference and applies written retry rules to recommend what to do and what to tell the customer.

4

Patterns and prevention

Upload a batch to see what's recoverable now and which repeated problems to fix.

How it was built

A measured path from reference data to reliable recommendations.

1

Built the reference

Mapped 200 decline codes from NPCI, ISO 8583, Razorpay, Cashfree and Stripe into 18 root causes.

2

Wrote the test set first

50 scenarios with expected answers, including trick cases and made-up codes, plus 10 kept aside.

See the test set
3

Tested a simple version (v1)

One AI prompt: right cause 82–84% of the time, right retry decision 70–74%, and it invented answers for 4 of 6 codes it should have refused.

4

Rebuilt it (v2)

Reference lookup first, then AI with written rules: right cause 100%, right retry decision 98%, and no invented answers.

5

Checked the rules

Audited every retry and compliance rule against current NPCI, RBI and card-network sources, and fixed three that were out of date.

Scores are on the 50-scenario development set.See full results