SparkGPT vs Siena AI (2026): A $750 Platform Fee or Pay Per Sale?

What Siena AI does well

Siena is a serious product with a strong customer list, and a fair comparison starts there.

It is built for support at scale. Siena answers customers across email, chat, SMS, WhatsApp, Instagram, Facebook and TikTok. It can look up orders and, through its price matching action, check a purchase date and issue a partial refund through Shopify without staff stepping in. Siena says brands automate up to 80% of customer interactions. That is a vendor figure, but it shows the main job: taking tickets away from your team.

It works with the helpdesk you already have. Siena's site says it sits on top of Zendesk, Kustomer, Gorgias, Dixa and others, and that you can change helpdesks without losing it. Its integrations page also lists Gladly and Intercom.

It does more than sell or support. Separate agents cover quality checks and review replies, and a memory layer carries customer context across conversations.

It has real momentum. On October 6, 2026, Siena announced a $17 million Series A led by York IE. It says it works with hundreds of brands, naming SPANX, FIGS, HexClad and Comfrt. Its pricing page lists SOC 2 Type II, SAML SSO, audit logs and a named success manager.

Setup is done for you. Siena's implementation team runs setup from the first day. If you have a large catalog and detailed brand rules, that hands on help has real value.

Does Siena AI sell, or only support?

It does both, with support as the center of gravity. The Shopping Agent page promises to turn conversations into purchases, and it shows friendly product recommendations and answers to product questions. A customer testimonial on that page describes add to cart buttons in live chat and a revenue dashboard. Siena's Gorgias comparison page says the agent tracks revenue attribution from first conversation through purchase.

Two things are worth checking on a demo. Siena's site navigation places a "Coming soon" label near its agent list without saying clearly which agents it covers, so ask whether the Shopping Agent is available to your account today. Its pricing page also does not list the Shopping Agent separately, so ask whether a shopping chat is billed like a support ticket.

Siena AI pricing in November 2026

The page closes with a form that asks for ticket volume, helpdesk, channels and goal, then promises "pricing that fits." So treat $750 plus $0.90 as a published starting point rather than your final quote. Two more gaps matter. Contract length is not stated. The term "automated ticket" is not defined on the pricing page, and Siena's blog and comparison pages describe the same unit as a conversation.

Siena also says it does not charge per seat, which is a real saving for a large support team. Your helpdesk subscription stays separate, because Siena sits on top of it.

The real difference: what triggers a charge

Siena charges for tickets its AI handles. Its blog reduces the formula to conversations times rate. The rate applies whether the conversation was about a late parcel or a purchase, and whether or not an order followed.

SparkGPT charges for attributed sales. When a visitor chats with the SparkGPT agent, the session is tagged. If that visitor places an order within 24 hours, the order is attributed to the agent, listed in the ROI dashboard and charged at 5%. Chats that end without an order cost nothing beyond the $2.99 base, and conversations are unlimited. The full price is on our pricing page, with no form to fill in.

Siena's case against outcome pricing

Siena has published its reasoning, and most comparison articles skip it. Its August 2025 post argues that with outcome pricing, "resolution" becomes a black box controlled by the vendor, that bills become hard to predict, and that vendors get pulled toward stretching definitions. It says Siena tracks revenue impact and other results, but that these metrics "guide optimization, not invoicing."

That argument was aimed mainly at per resolution pricing, but it deserves an honest answer here, because pay per sale is also an outcome model.

Where Siena is right. Any vendor that bills on its own attribution has a reason to credit more orders. A 24 hour window will also include some orders that would have happened without the chat. And a 5% fee does move with sales, so a record month costs more.

Where pay per sale differs. An order is easier to check than a resolution, because it exists in your store with a number, a time and a value. SparkGPT publishes its rule on the pricing page and FAQ, so you can match the ROI dashboard against your order list one line at a time. Our guide on how to measure chatbot attributed revenue shows how to run that audit and how to test for orders the agent did not really cause. The bill also moves with money coming in, and SparkGPT Growth runs on prepaid credits, where 1 credit equals $1. If the balance reaches zero, the agent pauses instead of charging you more.

SparkGPT is not the only tool billing this way. Several Shopify apps now take a share of attributed sales, so compare the rate and the window, not only the model. See our guide to performance based AI chatbot pricing.

The math: when is SparkGPT cheaper?

SparkGPT is cheaper whenever your monthly attributed sales are below (the other tool's monthly bill minus $2.99) divided by 0.05. Using Siena's published prices, and leaving out implementation because it is not public:

The third column is the one small stores should read. The $750 fee is fixed, so the headline $0.90 only comes close at high volume. At 200 tickets, you pay more than five times that rate.

SparkGPT's bill grows with sales instead:

The honest reading: this is only a like for like comparison if you are buying for the same job. A brand with 5,000 monthly tickets, a support team and a helpdesk is buying labor savings, and SparkGPT does not replace that. For a store that mainly wants more sales from website visitors, Siena's minimum published year is $9,000 before any tickets. A store whose agent is credited with $5,000 a month would pay SparkGPT $3,035.88 over the same year. If your agent drives more than about $33,000 a month and Siena would also automate 1,000 tickets, Siena can cost less than 5% and clear your support queue as well.

Feature comparison

Which one should you pick?

Pick Siena AI if you run an established brand with a real ticket queue, you use Zendesk, Gorgias, Kustomer or a similar helpdesk, you need coverage across email, SMS and social channels, and you want an implementation team to shape the AI around your brand voice.

Pick SparkGPT if your main goal is converting website visitors, you do not have a helpdesk or a support team, you want to see the full price without a form, or your site is not on Shopify. It installs on any site with one line of code:

<script src="https://admin.sparkgpt.ai/widget.js" data-api-key="YOUR_WIDGET_KEY"></script>
      

The two can also sit side by side if SparkGPT handles shopping questions on your site while Siena works your helpdesk queue, as long as you decide which one owns website chat. For setup, see adding an AI sales agent to Shopify. If you are comparing other tools, read SparkGPT vs Gorgias, SparkGPT vs Flyweight and SparkGPT vs Manifest AI.

Frequently Asked Questions

How much does Siena AI cost in 2026?

As of November 2026, Siena's pricing page lists a $750 monthly platform fee plus $0.90 per automated ticket. Support and implementation are listed without a price, and a form leads to tailored pricing. At 1,000 automated tickets a month, the published items come to $1,650 before implementation.

Does Siena AI have a free trial or free plan?

We did not find either on its pricing page. The page routes you to a pricing form, and the rest of the site points to booking a demo. The $750 fee does include an unlimited sandbox for testing once you are a customer.

Does Siena AI do sales or only customer support?

Mostly support, with a sales layer. Its Shopping Agent recommends products and answers product questions, and a customer describes add to cart buttons in live chat. Ask Siena whether it is available to your account and how shopping chats are billed.

Does Siena AI replace my helpdesk?

No. Siena says it sits on top of your existing helpdesk, such as Zendesk, Kustomer, Gorgias or Dixa. Your helpdesk subscription stays in place, so include it when you add up the total cost.

Does Siena AI charge based on sales?

No. Siena's blog says it tracks results such as revenue impact, but that those metrics guide optimization and do not affect invoices. It publishes no attribution window that we could find. Billing follows the number of automated tickets or conversations.

What attribution window does SparkGPT use?

24 hours. When a visitor chats with the SparkGPT agent, the session is tagged, and an order placed within 24 hours of that chat is attributed to the agent, listed in the ROI dashboard and charged at 5%. Orders outside that window, or from visitors who never chatted, are not charged.

Is SparkGPT cheaper than Siena AI?

It depends on tickets and sales. SparkGPT is cheaper whenever monthly attributed sales are below your Siena bill minus $2.99, divided by 0.05. At 1,000 automated tickets, that line is $32,940 in attributed sales. In a month with no attributed sales, SparkGPT costs $2.99.

Try it on your own store

Enter your store URL at SparkGPT and you will have a sales agent to test on your real catalog in about 10 minutes, free and with no credit card and no sales call. When you go live, you pay $2.99 per month plus 5% of the sales it is credited with inside a 24 hour window, and nothing for conversations that do not lead to an order. Questions? Write to hello@sparkgpt.ai.