The benchmark for branded, outcome-priced customer agents at Fortune 500 scale, now reaching into long-running sales and service goals with Horizon.
What it is
Founded in 2023 by Bret Taylor and Clay Bavor, Sierra runs voice and chat agents on its Agent OS for companies like Santander, Rocket Mortgage and Cigna, and reports serving over 40% of the Fortune 50. It charges for outcomes delivered rather than seats or tokens. Horizon (July 2026) lets agents pursue goals over days or weeks, like originating a loan.
Best for
- Fortune 500 customer experience
- Voice agents with brand personas
- Outcome-based buying
What we like
- Outcome-based pricing
- Top-tier voice quality and personas
- Strong simulation and testing
What to watch
- No public pricing
- Focused on customer-facing work, not internal operations
- Enterprise sales cycle
Where Sierra ranks
Alternatives and head-to-heads
Sierra vs Wonderful
The two heavyweights of enterprise CX agents. Sierra leads with US enterprise brands, premium voice and outcome pricing. Wonderful leads in non-English markets with local deployment teams.
Sierra vs Decagon
Both build top-tier customer agents across voice, chat and email. Sierra wins on voice and outcome pricing; Decagon on letting your own team change agent behavior fast.
Sierra vs Intercom Fin
Fin is the easiest way to add AI resolution to an existing helpdesk. Sierra is a standalone agent platform for enterprises that want a fully branded, voice-first experience.
Sierra vs SPIRITT
Sierra builds premium customer-facing agents for large brands and charges per outcome. SPIRITT is a general agent platform that also covers internal work.
Intercom Fin
Decagon
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