UPDATE: textmarks has an API. wow. there a total winner then http://textmarks.com/dev

Sorry I was sleeping> Anyways here is your answer. 1. If you are broke, like me then consider using an email to sms gateway. you will need to know the subscriber's provider. It can work if you are offering a one-way sms service such as updates. Watch out for SMSC spam catchers . 2. If you have money, but no time then you can use a provider such as Clickatell or Verisign and they will do all the background work. All you will need is an access to their API plus a monthly fee of 500-1500/month on top of SMS fees. 3. You have money plus time plus contacts then Forget all these guys and provision your own short-code, then start emailing your contacts at Verizon and them to give you access to their SMSC. When people say "I don't know how twitter pays for 250k SMS/month" they don't know that Twitter is probably paying less than your startup will for 10k SMS. that is the advantage of working directly with the carriers. SMS is super cheap for them. 4. You got money, but want to be careful, then I suggest http://mobivity.com or http://textmarks. This service charge you for zero to only a few bucks and give you a unique keyword plus short-code. You can easily talk to Greg Harris who is the CEO of Mobivity and he is very open to entrepreneurs looking to use his service which is why he has an API.I mean he will literally let you launch a product competing with his. Textmarks doesn't have an API to my knowledge but you can certainly email Ariel Poller. i would try something like apoller or a.poller@textmarks.com. Be smart when you choose a provider that offers a short-code.When you rent a shared short-code, it can change at any time and now your 50k users have to know your new short-code. If you are doing a interactive SMS service, that can suck. If you are going for the private short-code, then you are safe as a long as you can shell out 1000/month. If you are proficient with Mobile applications, the best way to go is to build your own messaging application. Now when someone sends you a SMS or you send your user a sms ask send them a link as well and ask them to download it. there you have it, no more SMS fees for that guy and your messages can be 500 characters long. OOps I gotta go make more coffee. Email me if you like and I can be more detailed, i just went on here without knowing exactly what you are doing.

What is the disadvantage of just using email addresses? Virtually every wireless company provides an email to sms gateway which basically gives each phone an email address. My current startup uses email addresses for 2 way interaction with the system via text messages so while slightly more difficult to configure initially, it's free!

Free yes, but as someone else mentioned, you don't have any guarantee of service quality. We used email-to-sms when prototyping Padpaw and got mixed results on message delivery. This is an important requirement as we're sending out change of event (i.e. "game rained out") messages. Also, using SMS for signup is a lot more straightforward for people - they can send it right from the phone.

Doesn't this require you to know which provider owns each number? We'd been considering going down that path, but couldn't find any decent way around it (and I don't consider asking customers which provider they're on decent.)

TMobile drops some of those at times. I'm not sure if it's just low priority or they randomly throw them away. It drops them outside of busy times, like late at night also.

the problem is that the cell carriers are also aware of this and from what I've heard from some people, unless you're yahoo they may block your mass company emails

are you doing this on a big scale yet? if so please share any other tips (especially on not getting blocked)

Not sure why they would block your messages. As long as they aren't spam (don't send unless the user opts in), then the cell provider makes 10-15 cents on every message you send. They should be more than happy to transport the messages for you.

good point - i guess it's just no guarantee of delivery then

Padpaw is currently using mBlox and they've been very helpful in getting us running and approved through all the carriers. We're using the XML interface for sending messages, but we might switch to SMPP if our volumes start getting insane. I wrote 3 blog posts regarding our experience. You can read about it here <http://www.padpaw.net/blog/?p=42>.

As far as pricing, expect to pay a monthly fixed fee and then a per message charge. I found mBlox pricing was the best.

Care to share the pricing of mBlox (privately if necessary). I'm currently paying Clickatell about 0.06 per message.

John.

I have been considering this, but sms gateways are more expensive then I can afford (I haven't found a good free one).

So I have been considering sending via a mobile phone or GSM/GPRS modem for now since I wouldn't have to scale it up very high for now: http://www.developershome.com/sms/freeLibForSMS.asp

One thing you can do is to send it through a phone directly, but that limits you to ~6 messages/minute.. That's not going to support a very large user base ;)

Gateways, such as http://www.bulksms.com/ generally charge $.05c/message, which is insanely high. Difficult to make money at those prices.

unless you have some special plan carriers in the US charge 5 to 10 cents per message anyway. Why would it be cheaper to send through your phone? I think as you start getting large volumes of SMS you can get some sort of volume discount (or run your own gateway).

You can configure Kannel (an open source SMS gateway) for use with your GSM modem/phone. However, as others have pointed out, this does not scale.

On top of the SMS gateway you'd also need to rent a number or lease a short code in order to receive messages. Short codes can take up to 90 days to become active and cost ~$1000 USD/month.

There are companies that allow you to use a shared dedicated short code and have an API to deliver mobile content - some will even do this for free (http://www.textmarks.com).

You can get a shortcode in three days - $500 for a random 5-digit, $1,000 for a vanity 5 or 6-digit. The biggest gating item is the approval process with the carriers. That will take 6-8 weeks.

If you're getting a prototype working, textmarks might be the way to go. You'll have to prefix your SMS command set with a keyword. Longer term you want your customers/members to identify with your own shortcode. Imagine them getting messages from two services on 41411

Right. The approval process with carriers is what makes getting a short code so time consuming. What was it like working with the Aggregators? I've heard mixed stories.

mBlox was good in getting us feedback and suggesting fixes during the process. You spend most of the time waiting for the carriers to respond to applications and testing.

from what i hear your own shortcode doesnt matter as people generally dont remember them anyway they just read them online/ on paper and text them

4info will handle all of your sms messaging for free: http://open.4info.net/gateway.jsp

Having ads attached seems like a potentially pretty high cost to me.

Ive looked into Clickatell.

For outbound it is expensive(5 cents). Inbound runs like 2 cents.

I use Clickatell and like the service. At 250k messages you're getting a 23% discount. At today's prices 250k messages will cost $12,000.

John.