Regex to Match Email address

Question

I have the below regex to match email address with atleast one @ and one .

[-0-9a-zA-Z.+_]+@[-0-9a-zA-Z.+_]+\.[a-zA-Z]{2,4}

Am wondering can it be simplified further to match email address with atleast one @ and one .?

Answer 1

Simple Regular Expression for Email Addresses

[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,4}

is one of the simplest possible. In many cases this simple expression is good enough. It consists of five parts:

[A-Z0-9._%+-]+ - the first part of mail address may contain all characters, numbers, points, underscores, percent, plus and minus.

@ - the @ character is mandatory

[A-Z0-9.-]+ - the second part of mail address may contain all characters, numbers, points, underscores.

\. - the point is mandatory

[A-Z]{2,4} - the domain name may contain all characters. The number of characters is limited between 2 and 4.

OPTION 2:

^(.+)@(.+)$ 

This one is simplest and only cares about ‘@’ symbol. Before and after ‘@’ symbol, there can be any number of characters.if you want to validate point(.) add \. into regular expression.

Answer 2

There are many edge cases to e-mail address structure that you will exclude if you try the simplest approach.

One I use that accepts most of the reasonably acceptable e-mail address looks like:

^(?:[w!#$%&'*+-/=?^`{|}~]+.)*[w!#$%&'*+-/=?^`{|}~]+@(?:(?:(?:[a-zA-Z0-9](?:[a-zA-Z0-9-](?!.)){0,61}[a-zA-Z0-9]?.)+[a-zA-Z0-9](?:[a-zA-Z0-9-](?!$)){0,61}[a-zA-Z0-9]?)|(?:[(?:(?:[01]?d{1,2}|2[0-4]d|25[0-5]).){3}(?:[01]?d{1,2}|2[0-4]d|25[0-5])]))$

which is preferable to the supposedly correct one:

(?<user>(?:(?:[^ \t\(\)\<\>@,;\:\\\"\.\[\]\r\n]+)|(?:\"(?:(?:[^\"\\\r\n])|(?:\\.))*\"))(?:\.(?:(?:[^ \t\(\)\<\>@,;\:\\\"\.\[\]\r\n]+)|(?:\"(?:(?:[^\"\\\r\n])|(?:\\.))*\")))*)@(?<domain>(?:(?:[^ \t\(\)\<\>@,;\:\\\"\.\[\]\r\n]+)|(?:\[(?:(?:[^\[\]\\\r\n])|(?:\\.))*\]))(?:\.(?:(?:[^ \t\(\)\<\>@,;\:\\\"\.\[\]\r\n]+)|(?:\[(?:(?:[^\[\]\\\r\n])|(?:\\.))*\])))*)

Note that all of the following addresses are perfectly acceptable as e-mail addresses:

        "[email protected]",
        "Somebody{MiddleName}[email protected]",
        "abc.\"defghi\"[email protected]",
        "Someone@[192.168.0.1]",
        "[email protected]",
        "[email protected]",
        "[email protected]",
        "[email protected]",
        "user@[IPv6:2001:db8:1ff::a0b:dbd0]",
        "\"much.more unusual\"@example.com",
        "\"[email protected]\"@example.com",
        "\"very.(),:;<>[]\\\".VERY.\\\"very@\\ \\\"very\\\".unusual\"@strange.example.com",
        "0@a",
        "!#$%&'*+-/=?^_`{}|[email protected]",
        "\"()<>[]:,;@\\\\\\\"!#$%&'*+-/=?^_`{}| ~  ? ^_`{}|~.a\"@example.org",
        "\"\"@example.org",
        "postbox@com",

The first regex only accepts some of these - only the second accepts all.

See here for a very good narrative on the subject.

Answer 3

It's important to have fraud detection, use libraries, validate tld, etc. However, you can achieve the latter using a complicated regex found here:

[a-zA-Z0-9.!#$%&’*+/=?^_`{|}~-]+@[A-Za-z0-9.-]+\.+(xn--vermgensberatung-pwb|xn--vermgensberater-ctb|xn--clchc0ea0b2g2a9gcd|xn--w4r85el8fhu5dnra|travelersinsurance|northwesternmutual|xn--xkc2dl3a5ee0h|xn--mgberp4a5d4ar|xn--mgbai9azgqp6j|xn--bck1b9a5dre4c|xn--5su34j936bgsg|xn--3oq18vl8pn36a|xn--xkc2al3hye2a|xn--mgba7c0bbn0a|xn--fzys8d69uvgm|xn--nqv7fs00ema|xn--mgbc0a9azcg|xn--mgbaakc7dvf|xn--mgba3a4f16a|xn--lgbbat1ad8j|xn--kcrx77d1x4a|xn--i1b6b1a6a2e|sandvikcoromant|kerryproperties|americanexpress|xn--rvc1e0am3e|xn--mgbx4cd0ab|xn--mgbi4ecexp|xn--mgbca7dzdo|xn--mgbbh1a71e|xn--mgbb9fbpob|xn--mgbayh7gpa|xn--mgbaam7a8h|xn--mgba3a3ejt|xn--jlq61u9w7b|xn--h2breg3eve|xn--fiq228c5hs|xn--b4w605ferd|xn--80aqecdr1a|xn--6qq986b3xl|xn--54b7fta0cc|weatherchannel|kerrylogistics|cookingchannel|cancerresearch|bananarepublic|americanfamily|afamilycompany|xn--ygbi2ammx|xn--yfro4i67o|xn--tiq49xqyj|xn--h2brj9c8c|xn--fzc2c9e2c|xn--fpcrj9c3d|xn--eckvdtc9d|wolterskluwer|travelchannel|spreadbetting|lifeinsurance|international|xn--qcka1pmc|xn--ogbpf8fl|xn--ngbe9e0a|xn--ngbc5azd|xn--mk1bu44c|xn--mgbt3dhd|xn--mgbpl2fh|xn--mgbgu82a|xn--mgbab2bd|xn--mgb9awbf|xn--gckr3f0f|xn--8y0a063a|xn--80asehdb|xn--80adxhks|xn--45br5cyl|xn--3e0b707e|versicherung|scholarships|lplfinancial|construction|xn--zfr164b|xn--xhq521b|xn--w4rs40l|xn--vuq861b|xn--t60b56a|xn--ses554g|xn--s9brj9c|xn--rovu88b|xn--rhqv96g|xn--q9jyb4c|xn--pgbs0dh|xn--pbt977c|xn--nyqy26a|xn--mix891f|xn--mgbtx2b|xn--mgbbh1a|xn--kpu716f|xn--kpry57d|xn--kprw13d|xn--jvr189m|xn--j6w193g|xn--imr513n|xn--hxt814e|xn--h2brj9c|xn--gk3at1e|xn--gecrj9c|xn--g2xx48c|xn--flw351e|xn--fjq720a|xn--fct429k|xn--estv75g|xn--efvy88h|xn--d1acj3b|xn--czr694b|xn--cck2b3b|xn--9krt00a|xn--80ao21a|xn--6frz82g|xn--55qw42g|xn--45brj9c|xn--42c2d9a|xn--3hcrj9c|xn--3ds443g|xn--3bst00m|xn--2scrj9c|xn--1qqw23a|xn--1ck2e1b|xn--11b4c3d|williamhill|rightathome|redumbrella|progressive|productions|playstation|photography|olayangroup|motorcycles|lamborghini|kerryhotels|investments|foodnetwork|enterprises|engineering|creditunion|contractors|calvinklein|bridgestone|blockbuster|blackfriday|barclaycard|accountants|xn--y9a3aq|xn--wgbl6a|xn--wgbh1c|xn--unup4y|xn--pssy2u|xn--o3cw4h|xn--mxtq1m|xn--kput3i|xn--io0a7i|xn--fiqz9s|xn--fiqs8s|xn--fiq64b|xn--czru2d|xn--czrs0t|xn--cg4bki|xn--c2br7g|xn--9et52u|xn--9dbq2a|xn--90a3ac|xn--80aswg|xn--5tzm5g|xn--55qx5d|xn--4gbrim|xn--45q11c|xn--3pxu8k|xn--30rr7y|volkswagen|vlaanderen|vistaprint|university|telefonica|technology|tatamotors|swiftcover|schaeffler|restaurant|republican|realestate|prudential|protection|properties|onyourside|nextdirect|newholland|nationwide|mitsubishi|management|industries|immobilien|healthcare|foundation|extraspace|eurovision|cuisinella|creditcard|consulting|capitalone|boehringer|bnpparibas|basketball|associates|apartments|accountant|yodobashi|xn--vhquv|xn--tckwe|xn--p1acf|xn--nqv7f|xn--ngbrx|xn--l1acc|xn--j1amh|xn--j1aef|xn--fhbei|xn--e1a4c|xn--d1alf|xn--c1avg|xn--90ais|vacations|travelers|stockholm|statefarm|statebank|solutions|shangrila|scjohnson|richardli|pramerica|passagens|panasonic|microsoft|melbourne|marshalls|marketing|lifestyle|landrover|lancaster|ladbrokes|kuokgroup|insurance|institute|honeywell|homesense|homegoods|homedepot|hisamitsu|goodhands|goldpoint|furniture|fujixerox|frontdoor|fresenius|firestone|financial|fairwinds|equipment|education|directory|community|christmas|bloomberg|barcelona|aquarelle|analytics|amsterdam|allfinanz|alfaromeo|accenture|yokohama|xn--qxam|xn--p1ai|xn--node|xn--90ae|woodside|verisign|ventures|vanguard|uconnect|training|telecity|symantec|supplies|stcgroup|software|softbank|showtime|shopping|services|security|samsclub|saarland|reliance|redstone|property|plumbing|pictures|pharmacy|partners|observer|movistar|mortgage|merckmsd|memorial|mckinsey|maserati|marriott|lundbeck|lighting|jpmorgan|istanbul|ipiranga|infiniti|hospital|holdings|helsinki|hdfcbank|guardian|graphics|grainger|goodyear|frontier|football|firmdale|fidelity|feedback|exchange|everbank|etisalat|esurance|ericsson|engineer|download|discover|discount|diamonds|democrat|deloitte|delivery|computer|commbank|clothing|clinique|cleaning|cityeats|cipriani|chrysler|catholic|catering|capetown|business|builders|budapest|brussels|broadway|bradesco|boutique|baseball|bargains|barefoot|barclays|attorney|allstate|airforce|abudhabi|zuerich|youtube|yamaxun|xfinity|winners|windows|whoswho|wedding|website|weather|watches|wanggou|walmart|trading|toshiba|tiffany|tickets|theatre|theater|temasek|systems|surgery|support|storage|statoil|starhub|staples|spiegel|singles|shriram|shiksha|science|schwarz|schmidt|sandvik|samsung|rexroth|reviews|rentals|recipes|realtor|politie|pioneer|philips|panerai|origins|organic|oldnavy|okinawa|neustar|network|netflix|netbank|monster|metlife|markets|lincoln|limited|liaison|leclerc|latrobe|lasalle|lanxess|lancome|lacaixa|komatsu|kitchen|juniper|jewelry|ismaili|iselect|hyundai|hotmail|hoteles|hosting|holiday|hitachi|hangout|hamburg|guitars|grocery|godaddy|genting|gallery|fujit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This is useful because it invalidates against the very common typo of .con vs .com