That is why you want to get in early.

Can some of these exchanges get together and create an open source exchange framework?

The free database on Heroku is limited to 10K rows and $9/month gets you 10 million rows.

Any ability to record?

No recording yet, but we're looking to have an archiving beta by the end of the year

I dont think it is in built but screen capture should work.

I switched languages 6 months ago. I now make more than I did as a Perl developer for 7+ years.

IF I were to validate by regex, I would put a confirmation for emails that I couldn't validate that read "We are very sorry but your email doesn't appear to be valid, however validating emails is very difficult so it may be our mistake. Can you confirm your email is correct?" And if they don't modify it, accept it as valid. It is an extra step but seems more friendly.

If you already have a layer of abstraction to your SQL statements, then it can be arguable. But if your are littering SQL statements everywhere, making changes to the database can be more tedious.

Also if you want to support more than one type database, I would use an ORM.

What would you do different based on what you know now?

While I was at a startup recently, I did all of my frontend development in Backbone.js, this app would do a lot better in that framework.

Also, the CI framework isn't all that great, I would have certainly used a different framework. Perhaps even Node.js (which is what I'm doing a lot of my development in nowadays).

I also would have looked for a marketer and devoted more time to the project. The market for this kind of product is very crowded, but there is a lot of room for innovation.

I'm curious why you would choose Node.js instead today. I've done a little Node.js work, and I would unequivocally use it again for anything that needs a fair amount of concurrency, or high volume, lightweight requests. Other than that though, the only advantage I see over other server side stacks is a slight mental bonus in using the same language on both the client and server? Are there any other major advantages you see over PHP/Python/Ruby,etc. stacks?

I don't think anyone's ever subscribed to a SaaS product because it used X technology over Y. I also think you're way too focused on the tech and the list of features, instead of selling a solution.

You can say all you want about invoicing being an over saturated market, but I launched a very successful project management product a few months ago. Focus on doing a few things very well, and you can do well in just about any "saturated" B2B space.

Spot on!

If you have Varnish then why have nginx? Is there an advantage to having nginx do the request routing?

I would think nginx would be better for holding open long "keep alive" connections than Apache or IIS if you are doing long polling etc.

Of course if you are just forwarding to another backend you may lose this.

Well, the sample is incomplete. Often, you also need a server for serving static files, which Nginx is really good at, but Varnish cannot do.

nginx can compress your HTTP traffic, while Varnish can't. So there are some things you would need nginx for.

However, I really think that nginx should implement proper support for WebSockets by now. I have requested this previously, but the request got unanswered.

FYI, compression was added to Varnish in 3.x:

https://www.varnish-cache.org/docs/3.0/tutorial/compression....