I am starting an online shopping portal in India. The company is registered in Tamil Nadu state in India. What are the sales tax obligations if i deliver products to customers outside of Tamil Nadu?

Whether the tax laws would be applicable to your startup is dependent upon the business model you intend to operate.   If you see the business model  of top e-commerce giants in india and worldwide, they operate on the market place model , where they just provide an online platform where buyers & sellers meet. They accept registrations from the sellers to list their product on the website & likewise they attract buyers based upon the portfolio of the products listed on their website , discounts & promotions. Here the online shopping portal is just acting as a bridge between the buyer & the seller. The portal is neither buying goods nor selling it.Its just providing a platform where the trade can take place. All the risk & the rewards that are normally associated with the sale of the goods lies with the seller & not with the buyer.   Revenue comes from commission that is charged by the portal to the seller, which is generally a percentage of the sales.   In this model , the portal is required to pay service tax only as it is providing the service of providing a market platform. No sales tax or CST would be applicable in this case   2) Trading Model   In this case , the portal acts as a reseller , wherein it procures goods from third parties , stocks the same in its warehouses & accordingly sells the same to the buyer via its online shopping portal.   In this case VAT , CST , Service Tax all would be applicable since here the portal is acting as a trader.   I Hope that answers your query ! :)