Decagon vs Sierra (vs Aissist): Cost and Resolution, 2026

By Alex Gomez, Sr. Analyst, Aissist.io · Published 31 August 2026 · Last updated 21 October 2026

Decagon vs Sierra is a choice between two enterprise AI agent platforms that publish no rate card, sell through sales teams, and — as of 20 October 2026 — are building different products. This page puts both side by side with Aissist.io, a self-serve alternative, and leaves the empty cells empty.

TL;DR: Sierra is becoming a place where transactions close and Decagon a gateway for customers' own AI agents; Vendr's buyer data puts Decagon's median contract at $432,750 a year, and neither publishes a fleet-wide resolution rate.

Methodology & sources

• Pricing, funding, ratings and customer claims read from vendor pages, G2, Vendr, Bloomberg and PYMNTS on 21 October 2026. Prices in USD.
• Performance figures are labelled by who published them. None of the three vendors' figures has been independently audited.
• Aissist figures: 83% average resolution and 4.8/5.0 CSAT on AI-resolved conversations, both vendor-claimed.
• Disclosure: this is Aissist's blog and Aissist is one of the three products compared. We'll declare the bias up front — and show our cons too.

How do Decagon and Sierra compare side by side?

Decagon and Sierra look alike on paper — enterprise-funded, sales-led, no public price — and differ mainly in scale and direction, while Aissist differs on price transparency and self-serve setup.

*2,000 tickets × 83% resolved = 1,660 billable resolutions at $0.20 (email) to $0.60 (chat) each. Run your own quote through the AI support price comparison tool.

Which resolution numbers can you actually check?

Only Aissist publishes a fleet-wide resolution rate; Decagon and Sierra publish single-customer case figures without a stated definition. That matters because the category's honest range is lower than most headlines.

The reality band comes from the two vendors that publish fleet averages. Ada reports a 52% average automated resolution rate across 550+ deployments, with most enterprise launches at 50–65%. Intercom reports a 76% average for Fin, counting conversations closed with no human involvement. Call it 52–76%, vendor-published on both ends.

Here is each vendor's flagship claim and the rebuttal it invites:

• Decagon — Duolingo, 80% deflection rate (case studies). Metric: deflection, not resolution. Definition on the page: none. Decagon's own glossary calls deflection a routing metric that ignores whether the issue was settled. (More on the difference in deflection vs resolution rate.)
• Sierra — Ramp, 90% case resolution (customer story). Metric: resolution. Definition on the page: none, and Sierra's billing criteria are agreed privately per customer.
• Aissist — 83% average resolution, 4.8/5.0 CSAT (homepage). Metric: resolution across customers. Definition: published on the pricing page — the AI fully resolves a genuine request without escalation. Rebuttal: it is vendor-claimed and unaudited.

"With Decagon, it's been a night-and-day difference." — Ian Riggins, Senior Operations Manager, Duolingo, Decagon case studies

A deflected ticket and a resolved ticket can be the same ticket. They can also be a customer who gave up.

What did each vendor ship on 20 October, and why does it matter?

On the same day, Sierra shipped a way for its agent to take payment mid-call, and Decagon published a playbook for policing customers' AI agents — two different bets on where support goes next.

Sierra's Stripe integration moves the caller into a secure keypad mode, routes card details to Stripe, then returns to confirm. Sierra reports that when Cedar's patients start a payment with its agent, 71.3% of those calls end in a successful payment. That is a transaction metric, and a clean one: it names the denominator.

"The Sierra agent takes care of the straightforward issues." — Ben Levick, customer operations and conversational AI lead, Ramp, Sierra customer story

Decagon's guide argues that personal agents are already contacting businesses, and recommends detecting them, giving them a dedicated channel, and scoping their authority by risk — through its PACT protocol and Personal Agent Gateway. Sierra, for its part, co-launched a rival standard, the Personal Agent Protocol, with Meta on 7 October. Two protocols in two days is how standards wars usually start. (We break down the Sierra–Meta draft in our protocol explainer.)

The demand is real. A Gartner survey of 3,566 customers found customers were about three times more likely to use third-party GenAI tools than company chatbots in their latest service interaction.

"Service leaders should not use GenAI as a mandatory first step for every issue." — Eric Keller, Sr Director Analyst, Gartner

Neither move makes the platform easier to drop onto an existing Zendesk or Intercom setup. Both make it a bigger thing to own.

What do Decagon and Sierra actually cost?

Decagon's contracts run from about $105,000 to $923,000 a year with a $432,750 median, per Vendr buyer data; Sierra has no independent price figure at all. Neither vendor publishes a rate card.

Vendr lists Decagon as mostly per-conversation, billed monthly. Decagon's pricing explainer confirms two models — per conversation, which most customers choose, and a higher per-resolution rate with no charge for escalations. For Sierra, G2 notes pricing is not listed by the vendor, and Vendr's Sierra page carries no contract data. Pricing on request is, technically, a price.

When we checked both vendors' sites this week, neither offered a trial or signup; both route to sales. That is normal for enterprise software and a real cost for a five-person support team, because the evaluation itself becomes a project.

Scale is also a risk signal now. PYMNTS reported on 13 October that Decagon had hired a bank to gauge buyer interest; ServiceNow denied any intention to buy. If you sign a multi-year Decagon contract, ask for change-of-control terms. For per-vendor detail, see our Decagon review and Sierra review.

Who should pick Decagon, Sierra or Aissist?

Pick by budget, team size and whether you want to keep your helpdesk — the three products barely compete for the same buyer.

• If you are a Fortune 500 brand with voice volume and a payments step, choose Sierra, because it now closes transactions in-call and has the deepest enterprise roster. See Aissist vs Sierra.
• If you run complex multi-step workflows and expect customers' AI agents in your queue, choose Decagon, because PACT and its gateway are built for exactly that. See Aissist vs Decagon.
• If you are an SMB or mid-market team that wants a published rate and to keep Zendesk, Intercom or Freshdesk, choose Aissist, because it connects to eight helpdesks including those three and charges only for resolutions.

"It doesn't invent answers; it stays inside the knowledge and procedures we gave it." — Nathaniel E., Co-Founder, small business, G2 review of Aissist.io

Aissist's cons, stated plainly: its 83% and 4.8/5.0 figures are self-reported, its SOC 2 status is "aligned" rather than certified, it discloses no funding, and 45 G2 reviews is a small base next to Sierra's 131.

The leaders are diverging, and neither is moving toward your stack

Decagon vs Sierra is no longer one decision with two price tags; it is a choice between a transaction surface and an agent gateway. Both suit large enterprises with six-figure budgets and months to deploy. Neither publishes a fleet resolution rate or a rate card. If your team is smaller, the useful question is not which leader to buy but whether you need either — or an agent that runs on the helpdesk you already pay for. Compare quotes in the price comparison tool before taking a sales call.

Want a published rate instead of a sales cycle? Aissist runs on your existing helpdesk and charges only for resolutions. See pricing →

Frequently asked questions

What do Decagon and Sierra actually cost?

Neither publishes a rate card. Vendr buyer data puts Decagon's median contract at $432,750 a year, ranging from $105,000 to $923,183; no independent Sierra figure exists, and G2 lists its pricing as unpublished.

Should a small team buy either Decagon or Sierra?

Usually not. Both sell through sales teams, offer no self-serve trial, and take one to two months to go live per G2 averages; a small team is better served by a per-resolution tool that runs on its existing helpdesk.

Is Decagon's 80% Duolingo figure a resolution rate?

No. Decagon labels it a deflection rate, and its own glossary defines deflection as contacts handled without a human, regardless of whether the issue was settled.

What did Sierra launch with Stripe?

On 20 October 2026, Sierra launched in-call payments with Stripe. Sierra reports 71.3% of Cedar calls where a patient starts a payment end in a successful payment.

What is Decagon's personal agent gateway?

Decagon's gateway detects customers' AI agents, routes them to a dedicated channel, and uses its PACT protocol to verify the agent's identity and the permissions the customer granted.

Which has better G2 ratings, Decagon or Sierra?

As of 21 October 2026, Decagon rates 4.7 from 30 G2 reviews and Sierra 4.5 from 131; Aissist.io rates 4.9 from 45.

Changelog

• 21 October 2026 — Added the 20 October Sierra and Decagon moves, the PACT and Personal Agent Protocol launches, resolution claim-and-rebuttal pairs, refreshed G2 ratings, and removed unsourced Sierra cost estimates.
• 31 August 2026 — First published.