Is opensea.io safe to use as a vendor?

opensea.io scored 96/100 on LynxRadar's security posture assessment. The domain meets baseline security requirements. 9 checks passed, 1 warnings, 0 critical issues across 10 passive checks including TLS, DMARC, security headers, breaches, and CVEs.

What TLS version does opensea.io use?

opensea.io uses TLSv1.3 with TLS_AES_256_GCM_SHA384. TLSv1.3 negotiated with TLS_AES_256_GCM_SHA384 (256-bit). Strong configuration with no deprecated protocols or weak ciphers detected.

Does opensea.io have DMARC configured?

Yes. opensea.io's DMARC policy is set to 'reject'. SPF record: yes. Strengths: DMARC policy set to reject (strongest); DMARC pct=100 — policy applies to all mail; Aggregate reports (rua) configured; SPF hard-fail (-all) configured; SPF DNS lookup count: 4/10 (within limit); DKIM configured (selectors: google, s1, s2, krs, zendesk1, zendesk2, smtpapi).

Does opensea.io have SPF configured?

Yes. SPF record found: v=spf1 include:_spf.google.com include:mailgun.org include:_spf.atlassian.net in...

Does opensea.io have security headers configured?

opensea.io has 4 of 5 recommended security headers. Present: X-Content-Type-Options, X-Frame-Options, Referrer-Policy, Permissions-Policy. Missing: CSP.

Does opensea.io use HSTS?

Partially. HSTS present but max-age is low (15552000s). Recommended minimum: 15768000 (6 months).

Has opensea.io been involved in a data breach?

No known breaches found. No known breaches found in public disclosure databases.

Does opensea.io have known CVE vulnerabilities?

Detected technologies: cloudflare. (cloudflare detected but excluded from CVE matching — upstream infrastructure). All detected technologies are upstream CDN/proxy infrastructure. No application-level software versions exposed.

Is opensea.io's SSL certificate valid?

Yes. Strengths: Certificate valid, 78 days remaining; Issued by Google Trust Services.

Does opensea.io have DNSSEC enabled?

Yes. Strengths: 2 nameservers configured (arch.ns.cloudflare.com., nicole.ns.cloudflare.com.); 5 MX records present; DNSSEC enabled; Zone transfers properly restricted.

HSTS present but max-age is low (15552000s). Recommended minimum: 15768000 (6 months).

opensea.io Security Report — Grade A (96/100)

Trust rating

Excellent · 96/100

Procurement snapshot

No critical findings. The 1 remaining item is a configuration gap, not an architectural problem.

Strengths

DNS Configuration

Known Breaches

TLS Configuration

Security Headers

Questions to ask

Confirm HSTS is enabled and its max-age setting

Estimated remediation effort: under an hour

Based on a passive external scan — supplement with vendor-provided attestations, not a replacement.

Trust Score Trend

→ No change 1 scan · Last scanned February 18, 2026

Score

100 75 50 25 0

opensea.io

96/100

Compliance & Certifications

Not yet verified

SOC 2 Type II

Audit report not on file

3rd party · AICPA

ISO 27001

Certificate not on file

3rd party · accredited body

GDPR

DPA not on file

Self-reported

CCPA

Self-reported

Incident History

No public breaches on record

Security Posture

1 item needs attention

9 passed

Increase how long HSTS stays remembered

HSTS Header

< 30 minutes Medium

This briefly reopens an interception window for returning visitors. HSTS is already turned on for opensea.io, which is good — but it's only set to be remembered for 0 day(s), well under the 6-month minimum that's considered safe. A short duration means a returning visitor's browser "forgets" the HTTPS-only rule quickly, briefly reopening the same risk HSTS is meant to close.

PCI-DSS 4.0Req 6.4.1

Application security header configuration

How to fix this

1Update the existing header to the value below (same place you originally added it). You're using Cloudflare in front of this site — add it there, see https://developers.cloudflare.com/rules/transform/response-header-modification/create-dashboard/.

Strict-Transport-Security: max-age=31536000; includeSubDomains; preload

2Confirm it's live: search "http header checker" and enter opensea.io.

HSTS guide

View all 9 passed checks

DNS Configuration

Known Breaches

TLS Configuration

Security Headers

CVE Exposure

DMARC / Email Security

MX Records & Mail Provider

Certificate Hygiene

Subprocessors & Tech Stack

Company Signals

Operational risk

Last funding

Employees

Trust Resources

Claim profile →

Trust Center

Not detected

DPA (Data Processing Agreement)

Subprocessors List

Tech Stack Detected

Subprocessors

CloudflareVercel

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