Enterprise AI Customer Service in 2026: Decagon, Sierra, Ada, Forethought, Cognigy
These five vendors do not publish a price card. Where a vendor does not publish a rate, we state what is on the record -- funding, ownership, pricing model, implementation timeline -- rather than substitute a buyer-reported aggregator ACV as if it were a vendor price. Always confirm pricing directly with the vendor before any procurement decision. Reviewed September 2026.
Side-by-Side: Enterprise Vendor Comparison
| Vendor | Pricing | Model | Deflection | Implementation | Source |
|---|---|---|---|---|---|
D Decagon | Quote only Not published | Per-conversation (enterprise quote) | 50-70%vendor-claimed | 8-16 weeks | decagon.ai |
Si Sierra | Custom outcome-based Enterprise-only | Outcome-based (pre-negotiated per resolution) | 60-80%vendor-claimed | 10-16 weeks | CNBC |
A Ada CX | Quote only Not published | Per-conversation default, per-resolution by exception (enterprise quote) | 40-60%vendor-claimed | 6-12 weeks | ada.cx |
Ft Forethought | Now part of Zendesk Quote only | Platform + committed deflection volume | 40-60%vendor-claimed | 8-12 weeks | Zendesk |
C Cognigy | Enterprise custom Large enterprise only | Enterprise custom pricing | 50-70%vendor-claimed | 12-20 weeks | Cognigy.com |
None of these vendors publishes a price card. Verify pricing directly with the vendor before purchasing.
Decagon
Contact sales- Deep conversational AI and action execution
- Multi-helpdesk native integrations
- Well-capitalised: $250M Series D at a $4.5B valuation (Jan 2026)
- Enterprise contract only; no self-serve trial
- 8-16 week onboarding timeline
- No published price card
Source: decagon.ai (Series D announcement, Jan 2026). Reviewed September 2026.
Deeper dive: Decagon AI vs Salesforce Agentforce head-to-head →
Sierra
Contact sales- Outcome-based pricing shifts resolution risk to vendor
- Strong regulated-industry track record (healthcare, fintech)
- Bret Taylor executive credibility ($950M Series E at a $15.8B valuation, May 2026)
- No published pricing or floor
- Enterprise-only (budget $200K+ recommended)
- Longest implementation timeline in the category
Source: CNBC May 2026, Sierra.ai public statements. Reviewed September 2026.
Ada CX
Contact sales- Per-resolution billing available as an exception, aligning incentives
- Strong multi-language support
- Established mid-enterprise CX deployments
- No published rate card -- all pricing negotiated
- Add-on costs for languages and custom workflows
- Requires a full enterprise quote process -- no self-serve
Source: ada.cx (pricing not published). Reviewed September 2026.
Forethought
Contact sales- Strongest multi-agent routing and triage capability in the category
- Now native to Zendesk (acquisition completed 26 March 2026)
- Mid-market heritage before folding into Zendesk
- Chat and email only -- no voice or WhatsApp native support
- Now a Zendesk product -- standalone roadmap and pricing folding into the Zendesk platform
- Independent go-forward pricing signal is uncertain post-acquisition
Source: Zendesk acquisition (26 Mar 2026). Reviewed September 2026.
Cognigy
Contact sales- Market leader in enterprise voice AI
- Best multilingual coverage in the category (50+ languages)
- Deep telephony integrations (Genesys, Avaya)
- Now backed by NiCE (acquisition closed 8 September 2025), available standalone and inside CXone Mpower
- Longest implementation timeline (12-20 weeks)
- Not viable for SMB or mid-market
- No free trial or self-serve option
- Go-forward roadmap now folding into the NiCE CXone Mpower platform
Source: Cognigy.com public materials + NiCE acquisition (8 Sept 2025). Reviewed September 2026.
Common Questions
How much does Decagon AI cost?
Decagon does not publish pricing. It sells via custom enterprise contract, priced primarily per conversation; the ACV figures that circulate are buyer-reported aggregator estimates, not vendor-published rates, so we do not state one. On the record: Decagon raised a $250M Series D in January 2026 at a $4.5B valuation (led by Coatue and Index Ventures), so this is an enterprise-scale product bought through a sales process, with an 8-16 week implementation on top of licensing.
How much does Sierra AI cost?
Sierra uses outcome-based pricing exclusively -- a pre-negotiated rate per autonomous resolution. Pricing is not published, and Sierra does not disclose ARR. Sierra raised a $950M Series E at a $15.8B post-money valuation in May 2026 (led by GV and Tiger Global), up from a $10B valuation in September 2025. All of this points to enterprise-only contracts (budget $200K+ recommended). Sierra is not a viable option for companies with budgets under $200K/year or implementations under 8 weeks.
How much does Ada CX cost?
Ada CX does not publish a rate card; all pricing is quote-based and negotiated per contract. Ada bills by conversation by default and by resolution as an exception. The dollar figures circulating for Ada (base-platform, per-resolution, and language or workflow add-ons) are buyer-reported aggregator estimates rather than vendor-published rates and vary widely, so we do not state a specific number. Expect a 6-12 week implementation and a full enterprise quote process.
How much does Forethought cost?
Zendesk completed its acquisition of Forethought on 26 March 2026; it is now offered as Forethought AI Agents by Zendesk and is being integrated into the Zendesk platform. Zendesk did not disclose deal terms. Pre-acquisition, Forethought was quote-only (a platform fee plus committed deflection volume); the standalone ACV figures that circulated were buyer-reported aggregator estimates, not vendor-published, and go-forward pricing is folding onto Zendesk's model, so we state no standalone number. Forethought's differentiation remains multi-agent routing and triage.
Compare Public-Pricing Alternatives
If any of the enterprise vendors above are out of budget or require more transparency, these vendors publish their pricing: