Reference
TL;DR
- Quick lookups, not learning. Find the code, the threshold or the deadline and get back to work
- Decline Codes for why a transaction failed. Reason Codes for why a chargeback was filed
- Time Frames for how long you have to respond. Miss that window and you lose automatically
- Want the concepts instead? Start at Payments, Chargebacks or Fraud
How to Use This Section
Find what you're after:
| Scenario | Go To |
|---|---|
| Transaction declined, need to know why | Decline Codes |
| Got a chargeback, need the reason code meaning | Reason Codes |
| Need to know how long you have to respond | Time Frames |
| Saw an acronym you don't know | Acronyms or Glossary |
| Want to know if your metrics are normal | Benchmarks |
| ACH payment bounced | ACH Return Codes |
Need the why, not the code? Start here:
- Payments - How transactions work
- Chargebacks - Dispute process explained
- Fraud - Prevention and detection
Typical Range Disclaimer
Everything marked "Typical" here assumes US domestic transactions at standard risk. Your numbers will differ. MCC, customer base, transaction mix and geography all move them.
What's Not Covered Yet
This site doesn't yet cover in depth:
- Marketplace/PayFac operations and compliance
- Crypto and stablecoin payments
- Cross-border payout optimization
- Card program management (issuer-side deep dives)
Might add them later, might not.
Popular
❌
Decline CodesPopular
Why transactions fail
🔢
Reason CodesPopular
Chargeback category lookup
⏰
Time FramesPopular
Response deadlines by network
📊
BenchmarksPopular
What 'good' looks like
📖
Glossary
Definitions and terminology
What You Need Right Now
❓
"Why was this declined?"
Decline codes explain authorization failures
❓
"What's this reason code?"
Reason codes explain chargeback categories
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"When do I have to respond?"
Deadlines by network and stage
❓
"What does this mean?"
Acronyms: AVS, CVV, ARN, TC40...
Card Networks
Card networks make the rules. Which one you're on decides your thresholds and programs.
🌐
Card Networks Overview
Visa, Mastercard, Amex, Discover - who does what and which rules matter
💳
Visa
VAMP program, 30-day response (see your notice), check your processor's written limit
🔴
Mastercard
ECM needs 100-299 chargebacks AND a 1.50-2.99% ratio; 45-day response, MATCH list operator
🔵
American Express
Closed-loop, inquiry process, 20-day response, premium cardholders
🟠
Discover
Smallest network, no published threshold or response window. Get your deadline from your acquirer in writing
Reason Codes by Network
Every chargeback has a code. The code tells you why. It also tells you what evidence you'll need to fight it.
💳
Visa
10.4 (fraud), 13.1 (not received), 13.2 (cancelled recurring)
🔴
Mastercard
4837 (fraud), 4853 (dispute), 4834 (POI error)
🔵
Amex
F29 (fraud), C08 (goods not received), C28 (cancelled recurring)
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Discover
UA02 (fraud), RG (not received), AP (recurring)
Decline Codes
Decline Codes - why an authorization failed, and what you can do about it.
The ones you'll see constantly:
- 05 (Do Not Honor) - the issuer's shrug. A retry sometimes works
- 51 (Insufficient Funds) - there's no money there
- 14 (Invalid Card Number) - a typo, or a test card
- 54 (Expired Card) - you'll need a fresh card on file
ACH Return Codes
ACH Return Codes - why ACH payments bounce.
The ones that matter:
- R01 (Insufficient Funds) - the common one. You can retry
- R10 (Unauthorized consumer debit) - use the ACH debit return rules
- R29 (Corporate Unauthorized) - R10's corporate twin
Response Deadlines
Time Frames - miss one and you've lost automatically.
| Network | Representment | Pre-Arb | Arbitration |
|---|---|---|---|
| Visa | 30 days (see your notice) | 30 days | 45 days |
| Mastercard | 45 days | 30 days | 45 days |
| Amex | 20 days | No such stage | No such stage |
| Discover | Not published | Not published | Exists, window not published |
Discover doesn't publish its dispute windows. Get them from your acquirer in writing, and work to the date on your notice.
Terminology
📖
Glossary
Definitions and terminology
🔤
Acronyms
AVS, CVV, ARN, TC40, etc.
🔍
Fraud Classification
Identify fraud types and responses
Next Steps
Looking up a code?
- Decline Codes - Auth failures
- Reason Codes - Chargeback categories
- ACH Return Codes - Bank returns
Need context?
- Payments Overview - How transactions work
- Chargebacks Overview - Dispute process
- Fraud Types - Threat landscape
Building a process?
- Benchmarks - What "good" looks like
- Time Frames - Critical deadlines
- Experimentation - Test safely
See Also
- Fraud Prevention - Stopping fraud
- Operations - Operational processes
- Playbooks - Step-by-step guides
- Network Programs - VAMP, ECM thresholds
- 3D Secure - Authentication
- AVS & CVV - Verification signals
- Chargeback Metrics - Tracking disputes
- Fraud Metrics - Measuring performance