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Kostenlose Online-Tools

268+ free online tools for PDF, images, SEO, developers, color, and productivity. Fast, browser-based, and private — no signup, no installs, no limits. Search above or browse by category below.

Total tools26810.8K total uses
Categories13Active categories
Most usedJSON Formatter4.1K uses
Recently addedExperiment RandomizerNewest tool
Password Generator
Create strong random passwords with custom length, character sets, and strength feedback.
Used 0 timesUpdated never
Password Strength Checker
Analyze password strength with entropy estimates, crack-time projections, and improvement tips.
Used 0 timesUpdated never
RSA Decrypt
Decrypt RSA-OAEP JSON payloads with your private key, including hybrid RSA + AES-GCM ciphertext.
Used 0 timesUpdated never
SSL Checker
Inspect TLS certificates for any public hostname — expiry, issuer, chain, cipher, and hostname match.
Used 0 timesUpdated never
SSL Expiry Checker
Check when a website SSL certificate expires. See days remaining, expiry date, chain validity, and renewal recommendations.
Used 0 timesUpdated never
DMARC Checker
Look up and parse DMARC DNS records for a domain. Review policy, reporting tags, and SPF alignment hints.
Used 0 timesUpdated never
IP Address Lookup
Look up geolocation, ISP, ASN, reverse DNS, and IP format details for any public IPv4 or IPv6 address.
Used 0 timesUpdated never
Reverse DNS Lookup
Look up PTR reverse DNS records for a public IP address. Resolve hostnames and verify forward DNS (FCrDNS) alignment.
Used 0 timesUpdated never
DNS Propagation Checker
Check DNS record propagation across global public resolvers. Compare answers from Google, Cloudflare, Quad9, and more.
Used 0 timesUpdated never
Subnet Calculator
Calculate IPv4 subnet details from CIDR notation or a subnet mask. Get network, broadcast, and host ranges instantly.
Used 0 timesUpdated never
CIDR Calculator
Analyze CIDR blocks, convert prefix lengths to subnet masks, split networks, and check whether an IP belongs to a range.
Used 0 timesUpdated never
SPF Record Checker
Look up and validate SPF TXT records for a domain. Parse mechanisms, count DNS lookups, and review policy strength.
Used 0 timesUpdated never