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Calculator
"Calculator" tools
Acceleration calculator
Battery calculator
Distance calculator
Electric Car calculator
Exponential growth
Fuel Cost calculator
Natural Gas calculator
Gladwell's 10000 hours
Speed converter
Frequency Calculator
Electrical power
Wavelength Calculator
Mortgage loan calculator
Code
"Code" tools
Bash boilerplate
Color
"Color" tools
CMYK conversion
HTML Color list
Pantone Color list
RGB conversion
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Data
"Data" tools
Bandwidth convert
Download calculator
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Music
"Music" tools
Beats-per-minute
Audio delay
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Song length
Music Scale
Tap your tempo
Photo
"Photo" tools
Aspect ratio
Composition Calculator
Depth-of-Field Calculator
DPI calculator
Image filesize calculator
Light calculator (EV)
Megapixel calculator
Megapixel Aspects
Video
"Video" tools
Audio file size calculator
Common bitrates
DCP file size
Foot-Lambert Calculator
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Frame rate convert
Video file size calculator
Web
"Web" tools
Content Security Policy
Redirection check
Security Policy Framework check
HTTPS config check
HTML char map
Emoji char map
HTML encoder
SEO Performance
Sender Policy Framework Check
Give the domain name as used for email addresses
domain
Check!
MX Email reception
No MX specified
Sender Policy Framework
SPF
(Sender Policy Framework) is an email authentication method designed to detect forging sender addresses during the delivery of the email. With SPF, there is an exhaustive list defined of the server IP addresses that are allowed to send emails for @domain.com addresses.
No SPF specified (no TXT records for this domain)
Examples
SPF: @amazon.com
SPF: @apple.com
SPF: @azure.com
SPF: @facebook.com
SPF: @gmail.com
SPF: @google.com
SPF: @googlemail.com
SPF: @icloud.com
SPF: @instagram.com
SPF: @microsoft.com
SPF: @nytimes.com
References
Sender Policy Framework
Open-SPF
