Matt King
Developer Advocate
Matt writes about fraud prevention, API integration patterns, and developer security. He focuses on practical guides that help engineering teams ship safer products.
Articles by Matt King
One Stolen Card, Twelve Accounts: Catching Cross-Account Fraud with Stripe Card Fingerprints
Fraudsters rotate emails, devices, and IPs for free, but stolen cards are scarce. Stripe's card fingerprint lets you catch the same card operating across multiple customer accounts. Here is how the signal works, the three patterns to watch for, and how to block a bad card for good.
July 29, 2026
Visa VAMP 2026: New Chargeback Thresholds and How to Stay Under 1.5%
Visa cut the VAMP merchant threshold to 1.5% on April 1, 2026, and acquirers now answer to a 0.5% portfolio limit. Here is how the new ratio is calculated, what counts against you, what does not, and the practical steps to stay clear of fees and account reviews.
July 26, 2026
1 in 8 Signups Are Disposable Emails: The 2026 Data and How to Fix It
New 2026 data reveals 12% of all form signups use disposable email addresses, and only 62% of submitted emails are actually valid. Here is the real cost, the detection methods that work, and implementation patterns to protect your platform.
July 22, 2026
Google's June 2026 Fraud Advisory: What AI-Powered Scams Mean for Your Fraud Stack
Google's June 2026 fraud advisory reveals a 1,210% surge in AI-powered scams. From deepfake voice cloning to synthetic identities, here is what developers need to know and how to harden your fraud prevention stack.
July 8, 2026
Fraud Prevention API Integration: From Zero to Protected in 30 Minutes
A step-by-step guide to integrating Fidro's fraud prevention API. Covers getting your API key, understanding risk scores, integrating into signup and Stripe checkout flows, and tuning your fraud thresholds.
June 24, 2026
IP Risk Scoring for Developers: How to Assess IP Reputation in Real Time
IP risk scoring helps you catch fraud at signup and checkout by analyzing VPN usage, proxy detection, Tor connections, data centre IPs, and geolocation anomalies. Learn how to integrate IP reputation checks and set scoring thresholds.
June 17, 2026
VPN Detection API for Developers: How to Detect and Handle VPN Users
VPN detection helps you identify users masking their real location. Learn how VPN detection works technically, how to integrate it into your app, and when you should (and should not) block VPN traffic.
June 10, 2026
How to Prevent Fake Signups Without Killing Your Conversion Rate
Fake signups pollute your funnel, waste resources, and skew your metrics. Learn how to stop disposable emails, bots, and multi-accounting with a tiered risk approach that keeps friction invisible for real users.
June 3, 2026
Best Email Validation APIs Compared: Features, Pricing & Developer Experience (2026)
An honest comparison of the top email validation APIs for developers. We evaluate Fidro, Kickbox, ZeroBounce, NeverBounce, Abstract API, and Hunter.io on features, pricing, response time, and developer experience.
May 27, 2026
How to Block Disposable Emails with an API (PHP, Node.js & Python Examples)
A practical guide to integrating disposable email blocking into your signup flow. Includes working code examples in PHP/Laravel, Node.js/Express, and Python/Flask, plus caching strategies and edge case handling.
May 20, 2026
Webhook Patterns for Stripe Fraud Prevention: Building Real-Time Risk Pipelines
Learn how to build a real-time fraud prevention pipeline using Stripe webhooks, Laravel queues, and Fidro's risk scoring API to catch suspicious transactions before they become chargebacks.
May 13, 2026
Friendly Fraud: When Legitimate Customers File Chargebacks (and How to Fight Back)
Friendly fraud accounts for up to 75% of all chargebacks. Learn why real customers dispute valid charges, the true cost to your business, and proven strategies to prevent and win disputes.
May 6, 2026
Bot Signups and Datacenter Abuse: Detecting Non-Human Traffic at Registration
Bots exploit your signup flow using datacenter IPs, headless browsers, and disposable emails. Learn how to detect non-human traffic at registration using IP intelligence, email validation, and behavioral signals.
April 29, 2026
Tuning Fraud Thresholds: How to Balance Security and Conversion
Setting fraud thresholds too high blocks real customers. Setting them too low lets fraud through. Learn how to find the right balance using precision, recall, and iterative tuning with risk score data.
April 22, 2026
How to Block Disposable Emails in Laravel, Node.js, Python & PHP
Code examples for blocking throwaway email signups in every major framework. Laravel validation rules, Express middleware, Django validators, Flask decorators, and raw PHP -- all using one API.
April 21, 2026
Card Testing Attacks: How Fraudsters Validate Stolen Cards on Your Checkout
Card testing attacks let fraudsters validate thousands of stolen card numbers through your checkout. Learn how these attacks work, the warning signs to watch for, and how to stop them with velocity limits, IP intelligence, and risk scoring.
April 15, 2026
Account Takeover Prevention: A Developer's Guide
Account takeover attacks cost businesses $13 billion annually. Learn how ATOs work, the signals that indicate an attack, and how to build layered defenses using email, IP, and behavioral analysis.
April 8, 2026
Email Bounce Rate: What It Is, Why It Matters, and How to Fix It
High email bounce rates damage your sender reputation and reduce inbox placement. Learn what causes bounces, how to calculate your bounce rate, and practical steps to bring it under control.
April 1, 2026
How to Detect VPN and Proxy Users on Your Website
VPNs and proxies hide a user's real location and identity. Learn how VPN detection works, when to block VPN users, and how to implement IP intelligence in your application.
March 25, 2026
Geolocation Fraud Detection: How Location Data Catches Bad Transactions
IP geolocation reveals mismatches between where a customer says they are and where they actually are. Learn how location intelligence catches fraud that email and card checks miss.
March 23, 2026
How to Reduce Your Stripe Chargeback Rate Below 1%
Exceeding 1% chargeback rate triggers Visa and Mastercard monitoring programs with fines up to $25,000/month. Here's a practical checklist for keeping your rate well below the threshold.
March 17, 2026
What Are Disposable Emails and Why You Should Block Them
Disposable emails let users create throwaway inboxes that bypass your verification flows. Learn how they work, why they damage your business, and how to detect them in real time.
March 10, 2026
How Chargeback Fraud Works and How to Prevent It
Chargeback fraud costs merchants billions annually. Learn the mechanics of friendly fraud, first-party fraud, and true fraud — and the practical steps to prevent chargebacks before they happen.
March 6, 2026
Email Validation API Integration Guide: Best Practices for Developers
A practical guide to integrating email validation into your signup flow. Learn where to validate, how to handle edge cases, and the patterns that reduce fraud without hurting conversion rates.
March 1, 2026
How to Detect Disposable Emails in Your Signup Flow
A practical implementation guide for adding disposable email detection to your registration form. Covers API integration, response handling, user messaging, and the edge cases that trip up most implementations.
February 28, 2026
Free Email Providers vs Disposable Emails: What's the Difference?
Gmail, Yahoo, and Outlook are free but legitimate. Mailinator, Guerrilla Mail, and 10MinuteMail are disposable and risky. Learn how to tell them apart and why the distinction matters for fraud prevention.
February 18, 2026
Email Validation for SaaS: The Complete Guide
Everything SaaS teams need to know about email validation — from basic format checks to advanced disposable detection, risk scoring, and integration patterns that protect revenue without killing conversions.
February 5, 2026
The True Cost of Fake Signups: What We Found Analyzing 10,000 Accounts
We analyzed 10,000 SaaS signups to measure the real impact of fake accounts. The results: 23% used disposable emails, they cost 4.7x more in infrastructure per dollar of revenue, and they destroyed conversion metrics.
January 22, 2026
What Is a Risk Score? How Fraud Risk Scoring Works
A risk score is a numerical value that represents the likelihood a user or transaction is fraudulent. Learn how risk scores are calculated, what signals they incorporate, and how to use them in your application.
January 8, 2026
IP Intelligence: How to Detect VPNs, Proxies, and Tor at Signup
IP intelligence reveals whether users are masking their location with VPNs, proxies, or Tor. Learn how IP analysis works, when anonymization is a fraud signal, and how to use it without blocking legitimate users.
December 18, 2025
Free Tier Abuse: How to Protect Your SaaS Without Hurting Real Users
Free tiers drive growth but attract abuse. Learn how to detect multi-account fraud, disposable email signups, and resource exploitation while keeping the experience smooth for legitimate users.
December 5, 2025
Stripe Radar vs Custom Fraud Prevention: When You Need Both
Stripe Radar provides baseline fraud protection, but it has blind spots. Learn when Radar is sufficient, when you need additional fraud detection, and how to layer them effectively.
November 20, 2025
How to Fight a Stripe Chargeback (and Win)
A practical guide to responding to Stripe chargebacks with compelling evidence. Learn which dispute reasons you can win, what evidence to submit, and how to automate the process.
November 5, 2025
Pre-Transaction Fraud Detection: How to Catch Bad Actors Before Payment
Pre-transaction fraud detection evaluates risk signals before payment is processed. Learn why validating emails, IPs, and geolocation before checkout prevents chargebacks and saves revenue.
October 20, 2025
Adding Email Validation to Laravel: A Step-by-Step Guide
Learn how to integrate real-time email validation into your Laravel application using a custom validation rule, service class, and queue job for async processing.
October 1, 2025
Building a Fraud Prevention Middleware in Node.js
A step-by-step tutorial for building Express middleware that validates emails, checks IPs, and scores risk before requests reach your application logic.
September 15, 2025