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Shopping For A Used Phone? PocketESN (And These Tips) Could Make Back Alley Craigslist Deals A Little Easier


As an Android nerd and 2-year Sprint customer, one of the biggest cons I’ve found from being with a CDMA carrier is the sometimes painful process of swapping or purchasing used devices. Aside from the initial device I receive when signing up for a 2-year agreement, my devices are almost always obtained through face-to-face meetings with sellers on Craigslist. A few quick protips I’ve learned through the years are:

  1. Always bring a friend
  2. Have them video record the transaction from the car
  3. Call minutes before meeting up to make sure the buyer has the full amount agreed to (to avoid getting short changed at the time of transaction)
  4. And most importantly… always check ESN’s.

“ESN” is short for a phone’s Electronic Serial Number. CDMA carriers use this to track devices on their network. Unlike GSM carriers that use SIM cards like T-Mobile and AT&T, a phone on carriers like Sprint or Verizon can easily be blacklisted if they’ve been reported lost, stolen or damaged. You can see why checking a device’s ESN is a crucial step in the buying process to avoid getting burned.

But checking an ESN isn’t always easy. A cautious seller may not want to provide you with the info over the phone as to avoid the device being activated without payment. The smartest way to go about it is in a face-to-face meeting with the seller. This way you can see firsthand, the device’s ESN (typically found underneath the battery). Even then, a shyster could replace the ESN sticker with one from a different device. The most full-proof method of checking a device is jumping into the phone’s Settings > About Phone > Status. No way to fake that (unless it’s rooted).

Okay, so now you have the ESN, we can start the process of making sure it’s clean. You can do this by either calling the carrier (a tedious process that can take a lot of time), jumping online to a free ESN checking sites (in which case you’ll have to read and type out that long ESN number accurately (I always mess up). Or as Nicole Cozma on Cnet pointed out — there’s a free app that will do everything for you.

PocketESN, is a free app in the Google Play store that will check the ESN of any device it’s installed on. It’s pretty straight forward. Install. Check. Get on with your life. PocketESN comes in both a free version that will only check the phone once, or a slightly more pricey paid version for $6 that will check any device, as many times as you’d like (even comes with a handy barcode scanner for quick ESN entry).

The only problem I’ve found with the free version of the app is, in a real world situation, it would require either the buyer or seller to sign into their Google account before at the time of the transaction in order to download from the Play store. Or, you could always back up the app using your preferred cloud service and then sideload. Either way, an active internet connection would be required and not exactly ideal for every situation.

You guys do any used phone shopping on Craigslist? Got any helpful tips? Could you see this app being useful, or would jumping onto in the browser be all around easier?

[Play Store Link]

Chris Chavez
I've been obsessed with consumer technology for about as long as I can remember, be it video games, photography, or mobile devices. If you can plug it in, I have to own it. Preparing for the day when Android finally becomes self-aware and I get to welcome our new robot overlords.

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  1. The thing is, ESN’s can be stolen. Pocket ESN communicates directly with the carrier to nullify this, while websites like checkesnfree are third parties, so cloned ESN and all other forms of nonsense are still “passable.” Also, there’s no point in taking all the time to browse some webpages when you can scan the ESN with PocketESN and be on your way. Well worth the money. Used it on two phones today actually.

    1. yep, PocketESN does NOT send your ESN off to 3rd party servers (shady ones or not), it directly users the carriers (I am the author of it, so I know this for a fact).

      I also don’t send threatening emails to my competitors, report them to Google and attempt to get carriers to lock them out, that the other mentioned provider did to me this week.

      1. Why would someone send you threatening emails and try to get you banned over an app that simply verifies ESN numbers? Do the other app/website owners think they deserve a monopoly or something? Baffled by the lamers.

        1. No freaking clue, I get this email from someone named “shane” claiming to have my source code, threatening me with the carriers etc. I google the email, its the owner of checkesnfree. I email him back “dude you are the owner of a checkesnfree”, then it gets all weird about how it wasnt him, it was his partner, but it was his gmail account.

      2. Excuse my ignorance… are carrier’s ESN blacklists actually available to third parties?

  2. I usually just tell people to meet me at the carrier’s store. Once the device is activated, cash goes over…. 

    1. Plus, the store is a safe place… lol

  3. I buy lots of craiglist, I try to activate it while I’m with them. Go online is easiest

  4. Seriously?? That happened? WTF!

  5. I disagree with the comment of using website. As someone who makes a secondary income weekly with buying and selling smartphones and electronics, I have made some of my best deals by being available with cash in hand at a moment’s notice. Using the websites have cost me money in the past. Calling the carrier was the only true way to get a straight answer and depending on the carrier that could mean long hold times. Before this app it was a bit more of a roll of the dice.

  6. I just meet people at the Verizon store when I sell my phones. That way we can just go in the store and have the ESN checked or to activate it if they want. The Verizon reps are surprisingly cool with it, even giving change for a $20 to the girl I sold my last phone to. 

  7. I’ve never had a CL issue. However, it also depends on the ‘newness’ of the device. If its fairly new, I find Ebay to be a far safer and better choice. If its older and I want a better price or a better resale, I use CL. But, I meet in popular areas and if I’m buying I’ll take the few mins to call VZW to check the ESN before I buy.

    1. Hey, did you get your G-Nex case yet?? 

      1. check ebay –
        Black TPU High Gloss Skin Case Cover for Samsung Galaxy Nexus Droid Prime i515
        seller = zydistro
        $3.95 + free shipping!!!


        (change the 0 to o in dot com in link above)

        i bought this case and love it!!!

        1. Take a pic of your phone with it on and post it here :D

          1. i don’t have my G-Nex yet.  i’m still waiting for Hesse to get his ass in gear and release the thing.

      2. Yes, thank you. I just realized it came in mail yesterday. Fits really well and the lime green color is kinda cool. I was hoping for the darker color, but this is green is kind of fitting for android. The style of awesome.

  8. I’ve bought a couple phones from craigslist. My biggest suggestion would be to buy it from them in the store of your provider and have them check the esn right there and switch it before giving any cash.

  9. The only problem with meeting at a store is the fucking douchebag employees that treat the transaction like they are being robbed of their time.

    Cell providers need training courses to deal with this new trend.

  10. Thats why i’ve always prefered GSM. None of that ESN cr@p to deal with. but i did check the serial numbers and SIM tested when i bought my Nokia N900 and Nexus One. I also carry an aluminum bat handy in my car in case they try to screw me over lol.

    1. Both TMobile and AT&T have blacklists for IMEI. The cost for database access is just to high

      1. They can blacklist phones too? I’ve never heard of that… They just choose not to? Or?

  11. Other things that are fairly obvious to most, but maybe not all.  Check that all of the following work:
    -All hardware buttons work
    -Make sure headset and loudspeaker work
    -Check 2/3g radios (call voicemail and then go to a web site)
    -Check wifi radio
    -Check GPS
    -Ensure the touchscreen works in all areas.
    -Check LED flash
    -Record video to ensure mic works
    -Check moisture indicators
    -Ensure the phone shut down and starts up properly (I met one fellow where his phone just would not shut down, really weird issue)

    I think that’s it, besides the super obvious physical damage part of it.

    1. Check the usb port as well, on some phones (EVO4g) it is notorious for “falling out”. Once it happens its pretty much done.

      1. Ooooh! That’s a good one too!

  12. i recently bought 2 DROIDX2’s on ebay.

    made sure the MEID numbers were good before i even bid on them.

    worked out great.

  13. Chavez – you need to stop meeting guys in dark alleys.

  14. I generally use all the info you guys posted, and I have to make a phone call from the device. 

  15. so she does porn

  16. Never could understand why anyone would actually CHOOSE to use CDMA it has never come close to GSM in any respect !

    1. It’s secure for voice and works well. GSM works but is not secure.

  17. I usually tell people to meet me at the nearest police station. That’s the most successful way of sniffing out the crooks on cl.

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