If there’s one technology fashion brands are all in on, it’s chatbots.

During New York Fashion Week, Tommy Hilfiger launched a Facebook Messenger chatbot for its Gigi Hadid collaboration. It was the first brand to sell a see-now-buy-now collection through Messenger. Burberry went a slightly more content heavy route — its chatbot, launched during London Fashion Week this week, provides behind-the-scenes looks at the inspiration for its London Fashion Week show collection. The bot also lets you enter a maze that asks you to navigate through pictures and GIFs. Once you get through that, you can make purchases from the collection.

Chatbots are popular in fashion for obvious reasons. It brings an element of the in-store experience online, letting people speak one-on-one with customers. JackThreads CEO Mark Walker told Glossy previously that Facebook Messenger is beloved by the brand because it’s very intimate. And it also has data points on shopper behavior, something other social platforms don’t provide. Facebook is the most popular chatbot tool for fashion, probably because of sheer user size: Facebook Messenger has over 900 million users and 50 million businesses use it to speak to customers, according to the platform. Microsoft, WhatsApp and Kik are also big in the bot space, with brands like Sephora using Kik to recommend beauty products. IBM’s Watson is also working with The North Face to guide online shopping.

“Messaging apps provide this immediate and intimate thing,” said Mariah Chase, CEO of plus-size retailer Eloquii. “And in retail, there is a never-ending quest for channel expansion. Wanting to be everywhere.”

The issue comes when retailers need to figure out what exactly to provide through a bot. Some go end-to-end, letting you buy things right from the bot. That is hard to implement, say experts: Chase said that having updated inventory can be technically challenging. Facebook still forces you to leave the bot in order to actually check out, another frustration for retailers.

“What can and will be powerful to us will be a one-to-one customer conversation which helps her put looks together in a rapid fire, immediate and visual interface, whether or not she completes the transaction there,” said Chase.

Online retailer Boohoo, which recently shifted its focus to mobile shopping is also testing different bot or intelligence systems, according to a spokesperson, who could not provide additional comment.

(It’s not just fashion brands with bots: retailers like 1-800 Flowers also use them to update delivery statuses and ask for feedback, while publisher like the Guardian are using them to send news updates.)

The next step, according to retailers, is figuring out “personality” for the bot. The novelty and ease of using a text-message interface on Facebook or another platform is the first step, but next will be the harder step of trying to make your bot sound like your brand. To that end, the Tommy bot tries to capture what it might be like to talk to Hadid herself, since the bot is promoting the collaboration between the model and the brand.

Spring, the mobile marketplace company, was one of the first companies to experiment with Messenger, launching a presence once Facebook opened up the service to brands in April. It’s more of a choose-your-own-adventure bot, letting you find things like the right boots or dress in the price or style you want. But it has generally been deemed not a success, with experts in the space saying that brand-specific bots could be a better experience, since they can provide more of a targeted feel. Spring declined to comment for this article.

The other big issue with bots is how clunky the experience itself can be. Often, customers will ask the bot for an item, or something to pair an existing item with. Then the bot has to check inventory and come back to the customer. If questions are more complicated, like “what shoes go with that dress?” bots may have to send a message to a store stylist. The bot technology is nowhere as seamless as it needs to be, and for elevated fashion brands all about experience, that can be a problem.

It’s also not easy to build a bot, so resources often hold back fashion brands from investing in teams to build the tech. While Facebook is out pushing the technology heavily, internal investment holds them back. “We want to do this, but we’re a ways away from being able to,” said Eloquii’s Chase.