readwise.io

We performed a comprehensive analysis of readwise.io on 2026-06-30. The website returned an HTTP 200 status code with a server response time of 27793ms. The page is served over HTTP/2 protocol with Gzip compression enabled, achieving approximately 60.0% size reduction. The total page weight is 104 KB, and the site is served behind a CDN (Content Delivery Network). The website uses a secure HTTPS connection with a valid SSL certificate issued by Google Trust Services (DV type). The connection is encrypted using TLS 1.3 with the TLS_AES_256_GCM_SHA384 cipher suite and ECDSA-SHA256 signature algorithm. The certificate covers 2 domain(s) (Subject Alternative Names) and expires on 2026-09-26, which is 88 days from now. The security headers analysis reveals a score of 65/100 (moderate). The following security headers are properly configured: Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, and Referrer-Policy. However, the site is missing Strict-Transport-Security (HSTS) and Permissions-Policy, which could expose the site and its users to cross-site scripting (XSS), clickjacking, and other web-based attacks. Our technology detection scan identified 12 technologies across 11 categories powering readwise.io. The detected stack includes React, Webpack, Vite, Google Analytics 4, Google Tag Manager, New Relic, Cloudflare Turnstile, Cloudflare, GitHub Pages, Google Fonts, jQuery, and Font Awesome. The UI is built with React. Based on our comprehensive analysis of domain age, SSL configuration, email authentication, security headers, and blacklist status, readwise.io receives an overall trust score of 76/100, classified as "Likely Safe".

After conducting a thorough safety and legitimacy analysis, readwise.io receives a trust score of 76/100, which places it in the "Likely Safe" category. This score is calculated by evaluating multiple factors including SSL certificate validity, domain registration history, email authentication protocols, security header configuration, and blacklist status across major threat intelligence databases. The analysis identified several positive trust signals: a valid HTTPS connection protecting data in transit, a valid SSL certificate issued by Google Trust Services with 88 days until expiration, SPF (Sender Policy Framework) email authentication preventing email spoofing, and DMARC email authentication with a none policy. Areas of concern include: the domain's WHOIS information is hidden behind a privacy service, making it harder to verify the owner's identity and DNSSEC is not enabled, leaving DNS queries vulnerable to spoofing attacks. While these issues don't necessarily indicate malicious intent, they represent areas where the website's security posture could be improved. We checked readwise.io against 8 major blacklist databases including Google Safe Browsing, Phishtank, Urlhaus, Openphish, Dnsfilter, Spamhaus Dbl, Surbl, and Virustotal. The domain passed all 8 checks with a clean status, meaning it has not been flagged for phishing, malware distribution, spam, or other malicious activities by any of the tested threat intelligence providers.

Our technology detection engine scanned readwise.io and identified 12 distinct technologies across 11 categories. This analysis is performed by examining HTTP response headers, HTML source code patterns, JavaScript library fingerprints, CSS framework signatures, and DNS records. UI Library: React — handles the user interface rendering and component management for readwise.io. Build Tool: Webpack and Vite — bundles and optimizes the JavaScript and CSS assets for readwise.io. Analytics: Google Analytics 4 — tracks visitor behavior and provides traffic insights for readwise.io. Tag Manager: Google Tag Manager — manages marketing and analytics tags without code changes for readwise.io. Monitoring: New Relic — monitors application performance and errors for readwise.io. Security: Cloudflare Turnstile — provides security features like bot detection and CAPTCHA for readwise.io. CDN: Cloudflare — accelerates content delivery by caching assets at edge locations worldwide for readwise.io. Hosting: GitHub Pages — provides the server infrastructure for readwise.io. Fonts: Google Fonts — delivers web fonts for typography for readwise.io. JavaScript Library: jQuery — provides utility functions and DOM manipulation for readwise.io. Icon Set: Font Awesome — provides additional functionality for readwise.io. We also extracted the following tracking identifiers: Google Tag Manager container GTM-5XMQFPT. These IDs can be used to identify other websites operated by the same organization.

readwise.io delivers its homepage in 27793ms (server response time), which is considered slow by industry standards. The total page weight is 104 KB, and we detected 139 resource requests loading assets from 14 third-party domains. A high number of third-party domains can significantly impact page load time due to additional DNS lookups and TLS handshakes required for each domain. The website uses Gzip compression for text-based assets, achieving an estimated 60.0% reduction in transfer size. This reduces bandwidth usage and improves page load times, especially for visitors on slower connections. Asset minification status: 3 out of 12 CSS files and 3 out of 6 JavaScript files are minified. Minifying the remaining 12 unminified file(s) could further reduce page weight by 10-30% for those assets. Minification is a best practice that reduces download sizes without affecting functionality. The site is served through a Content Delivery Network (CDN), which caches static assets at edge servers around the world. This means visitors from different geographic regions receive content from the nearest edge server, significantly reducing latency. CDN usage is particularly important for websites with a global audience, as it can reduce page load times by 40-60% for distant visitors. From an environmental perspective, each page view of readwise.io produces approximately 0.05g of CO₂, earning a carbon rating of A. This places the website among the cleanest on the web, demonstrating efficient use of server resources and optimized content delivery. For reference, the average web page produces about 0.5g of CO₂ per page view. The page weight of 104 KB is the primary factor in this calculation. Core Web Vitals data from the Chrome User Experience Report (CrUX) is not available for readwise.io. This typically means the site doesn't have enough real-world Chrome user traffic to generate statistically significant field data, or the domain is not included in the CrUX dataset. Core Web Vitals (LCP, INP, CLS) are important Google ranking factors that measure real user experience.

readwise.io resolves to the IPv4 address 104.26.9.37 and also supports IPv6 (2606:4700:20::681a:825), demonstrating modern network infrastructure readiness. The domain has 3 A record(s) configured. The domain name system is managed by 2 name servers: cory.ns.cloudflare.com and ines.ns.cloudflare.com. Having 2 name servers provides good redundancy — if one fails, the others can continue serving DNS queries. The choice of name servers often indicates the DNS hosting provider or CDN service being used. Email for readwise.io is handled by Google Workspace with 5 MX records configured: aspmx.l.google.com, alt1.aspmx.l.google.com, and alt2.aspmx.l.google.com and 2 more. Multiple MX records provide failover redundancy — if the primary mail server is unavailable, email will be routed to the next available server. SPF (Sender Policy Framework) is configured, which specifies which mail servers are authorized to send email on behalf of this domain. This helps prevent email spoofing and improves email deliverability. DMARC (Domain-based Message Authentication, Reporting and Conformance) is configured with a none policy — a monitoring-only setting that doesn't enforce any action on unauthorized emails. DKIM was not detected. Without DKIM, recipients cannot cryptographically verify that emails claiming to be from this domain are authentic. DNSSEC is not enabled for readwise.io. While not critical for most websites, DNSSEC adds an important security layer by ensuring DNS responses haven't been tampered with during transit. Enabling DNSSEC is recommended for domains handling sensitive data or financial transactions. Our subdomain enumeration scan discovered 10 active subdomains for readwise.io: admin.readwise.io, api.readwise.io, app.readwise.io, blog.readwise.io, cdn.readwise.io, dev.readwise.io, m.readwise.io, and mail.readwise.io. Plus 2 additional subdomains. Active subdomains can reveal the organization's infrastructure, including development environments, API endpoints, and third-party service integrations.

The homepage of readwise.io contains 442 words of visible text content. This is a moderate amount of content. The page is structured with 10 H2 headings, 0 H3 headings, 3 H4 headings, 1 H5, and 2 H6 headings. The page includes 48 images. 2 images (4%) are missing alt text attributes, which is a significant concern for both accessibility and SEO. Screen readers rely on alt text to describe images to visually impaired users, and search engines use alt text to understand image content. Only 96% of images have proper alt text — we recommend adding descriptive alt attributes to all images. The link structure consists of 26 internal links pointing to other pages on the same domain and 37 external links pointing to third-party websites. There are 6 external JavaScript files, 12 CSS stylesheets, and 1 iframes on the page. The site implements the following web standards and features: robots.txt (controls search engine crawling behavior) and Progressive Web App (PWA) manifest (enabling app-like installation). Notable missing features: XML Sitemap and Schema.org structured data. Adding these could improve search engine discoverability and rich result eligibility. We detected the following payment methods accepted on readwise.io: Discover. Offering multiple payment options including credit cards and digital wallets improves customer trust and can increase conversion rates. The website has social media presence across 3 platforms: Facebook (@readwise.io), Twitter (@Nneuman), and Github (@newrelic). An active social media presence is a positive trust indicator and helps build brand awareness and customer engagement.

The title tag for readwise.io is good at 8 characters: "Readwise". The length is acceptable, though it may be slightly truncated in some search result displays. The meta description is 144 characters (well-optimized): "Grow wiser and retain books better: Readwise sends you a daily email resurfacing your best highlights from Kindle, Insta...". Google typically displays up to 155-160 characters of the meta description in search results. A compelling meta description with a clear call-to-action can significantly improve click-through rates from search results. The page language is declared as en and a favicon is configured. Open Graph meta tags are configured with 4/4 recommended fields: OG title ("Readwise..."), OG description, OG image (social sharing thumbnail), OG type (summary). These tags control how the page appears when shared on Facebook, LinkedIn, and other social media platforms that support the Open Graph protocol. A Twitter Card of type summary_large_image is configured, which controls how links appear when shared on Twitter/X. The "summary_large_image" type displays a large image preview, which typically generates higher engagement rates than the basic card type.