SIZE XS
SIZE SM
SIZE MD
SIZE LG
For Investors
For Founders
Portfolio
Blog
Education Center
Events
Catalyst
Sign In
Join
For Investors
For Founders
Portfolio
Resources
Blog
Education Center
Events
Catalyst
Sign In
Join
Castle
castle.io
Mountain View, CA, United States
Castle prevents account takeover in web and mobile apps.
Loading Tweets...
Jobs
View Castle's careers page
Data Scientist
San Francisco, CA
Blog Posts
Is Puppeteer stealth dead? Not yet, but its best days are over
November 6, 2025
Fraudulent email domain tracker: October 2025
October 29, 2025
How to detect disposable email domains without relying on 3rd party APIs and lists
October 22, 2025
Roll your own bot detection: server-side detection (part 2)
October 15, 2025
Roll your own bot detection: fingerprinting/JavaScript (part 1)
October 8, 2025
Fraudulent email domain tracker: September 2025
September 30, 2025
Deep dive: how navigator.deviceMemory can be used for fingerprinting and bot detection
September 10, 2025
How we detected a CAPTCHA solver in the wild, and what it says about bot defenses
September 3, 2025
Why a classic CDP bot detection signal suddenly stopped working (and nobody noticed)
August 28, 2025
Fraudulent email domain tracker: August 2025
August 27, 2025
Finding links between fraudulent email domains using graph-based clustering
August 19, 2025
How to detect Open Bullet 2 bots running in Puppeteer mode
August 12, 2025
How to authenticate OpenAI Operator requests using HTTP message signatures
August 7, 2025
From detection to trust: the evolving challenge of AI bot authentication
August 5, 2025
From LLM scrapers to AI agents: mapping the AI bot landscape for detection teams
July 30, 2025
Fraudulent email domain tracker: July 2025
July 29, 2025
Bringing bot detection research to your AI-powered workflow
July 23, 2025
What browser fingerprinting tests like Amiunique and Browserleaks really show, and what they miss
July 16, 2025
How to detect Selenium bots?
July 16, 2025
How we hire at Castle
July 14, 2025
Detecting Gmail-based fake accounts: what Emailnator teaches us
July 9, 2025
How to detect Brave browser using HTTP headers and JavaScript
July 8, 2025
How to detect browser time zone using JavaScript
July 8, 2025
Bought sneaker proxies by mistake, did science with them anyway
July 2, 2025
CAPTCHAs 101: what they are, how they work, and where they fall short
July 1, 2025
Fake account creation attacks: anatomy, detection, and defense
June 27, 2025
Credential stuffing attacks: anatomy, detection, and defense
June 25, 2025
Fraudulent email domain tracker: June 2025
June 25, 2025
How bot detection misfires on non-mainstream browsers and privacy tools
June 17, 2025
From Puppeteer stealth to Nodriver: How anti-detect frameworks evolved to evade bot detection
June 11, 2025
What TikTok’s virtual machine tells us about modern bot defenses
June 4, 2025
Fraudulent email domain tracker: May 2025
May 27, 2025
What a Binance CAPTCHA solver tells us about today’s bot threats
May 20, 2025
Castle for Cloudflare: Unified bot and fraud defense, from edge to in-app
May 15, 2025
Detecting Hidemium: Fingerprinting inconsistencies in anti-detect browsers
May 13, 2025
Detect and crash Chromium bots with one weird trick (bots hate it!)
May 7, 2025
Fraudulent email domain tracker: April 2025
April 29, 2025
Understanding disposable emails
April 22, 2025
How dare you trust the user agent for bot detection?
April 16, 2025
Why traditional bot detection techniques are not enough, and what you can do about it
April 9, 2025
Analyzing anti-detect browsers: How to detect scripts injected via CDP in Chrome
April 2, 2025
Bot detection 101: How to detect bots In 2025?
March 25, 2025
How to detect Headless Chrome bots instrumented with Playwright?
March 19, 2025
How to detect Headless Chrome bots instrumented with Puppeteer?
March 13, 2025
Anti-detect browser analysis: How to detect the Undetectable browser?
March 5, 2025
Overview of anti-detect browsers
February 27, 2025
Antoine Vastel is joining Castle as Head of Research
February 21, 2025
Detecting noise in canvas fingerprinting
February 21, 2025
The role of WebGL renderer in browser fingerprinting
February 12, 2025
Anatomy of a 4-day mobile app credential stuffing attack
February 11, 2025
How bots and fraudsters exploit free tiers in AI SaaS
February 4, 2025
How bots and fraudsters exploit video games with credential stuffing
January 24, 2025
Open Bullet 2: The Preferred Credential Stuffing Tool for Bots
January 13, 2025
Canvas fingerprinting in the wild
December 27, 2024
Anatomy of a 6-day Credential Stuffing Attack From 2.2M Residential IPs
December 19, 2024
Fixing the blind spots in fraud prevention
October 15, 2024
Product Focus: Overview Page
April 9, 2024
8 Common Types of Account Abuse
August 14, 2023
Castle & Twilio Segment – Instant Account Defense
August 1, 2023
In Devices We Trust: Improving CAPTCHA Friction
July 21, 2023
How to Prevent Account Sharing Like Netflix
July 17, 2023
Using Zero Trust to reduce fraud and abuse
July 6, 2023
Which CAPTCHA(s) Should I Use?
June 29, 2023
Product focus: Policies
June 16, 2023
The Different Forms of Online Abuse
June 12, 2023
From Spam to Scams: How to Handle Fraud vs. Abuse
May 23, 2023
A Guide to Account Verification
May 17, 2023
Product focus: Time selector
May 11, 2023
7 Fraud Prevention Rules Using Device Fingerprinting
May 3, 2023
11 Ways to Pinpoint a User's True Location
May 1, 2023
9 Device Fingerprinting Solutions for Developers
April 21, 2023
7 Proxy Piercing Techniques: What Works in 2023?
April 7, 2023
Swiftly identify fraud rings with instant link analysis
February 16, 2023
Enhanced User Activity Monitoring
February 16, 2022
CyberNews Interview: Online businesses that handle money will be a target
February 1, 2022
A behavioral approach to device fingerprinting
November 17, 2021
Announcing the Event Explorer
July 28, 2021
Introducing the Detection of Multi-Accounting
June 7, 2021
Castle's API enhanced with Risk Signals
April 21, 2021
Introducing the React Native SDK
April 1, 2021
A Layered Approach to Bot Detection and ATO Prevention
March 25, 2021
Reducing Signup & Login Friction
February 25, 2021
Using Castle with OIDC Providers
February 16, 2021
Finding Signals in a Flood of Data
February 4, 2021
Bot or Not: Can you spot the automated mouse movements?
December 9, 2020
Joining Castle to help protect your online identity
October 12, 2020
Introducing the New Castle
October 9, 2020
How Effective Is Castle Against Credential Stuffing?
October 7, 2020
A UX Designer, Solutions Architect, and the Root of All Cool Things
August 28, 2020
How to Think About GDPR as a Security Vendor
July 24, 2020
Outsmarting ATO Threats
July 13, 2020
Protecting Consumer Identities Is a Team Effort
June 11, 2020
Managing ATOs When Online Engagement Is at a Peak [video blog]
May 28, 2020
Bad Bots vs SEO: Where Security and Marketing Collide
May 8, 2020
How We Built a Culture on Trust and Security
May 1, 2020
Defining AX: Attacker Experience
April 14, 2020
Introducing: Castle's Training Camp
April 8, 2020
Redefining Bot Detection: Why Identity Matters
March 11, 2020
Why Good Security Is a Profit Driver
February 13, 2020
Why More is Better for Attackers Perpetrating Account Takeover Attacks
January 21, 2020
Why Reputation is Everything When Perpetrating Account Takeover Attacks
January 8, 2020
How Acting Like Your Neighbor Helps Attackers Perpetrate Account Takeover Attacks
December 18, 2019
How Attackers Hide in Plain Sight When Perpetrating Account Takeover Attacks
December 11, 2019
How to Balance Security with Risk Tolerance and User Experience
November 20, 2019
[PODCAST] CISO Series Defense in Depth: User-Centric Security
October 17, 2019
Show all Blog Posts
(101 more)
Join FundersClub for Free
