# Sierra Alternatives (2026): 7 AI Support Agents Compared

> Source: https://theagentsindex.com/sierra/alternatives (curated, quality-gated, re-verified)

Sierra is Bret Taylor and Clay Bavor's enterprise agent platform for customer experience: branded agents that resolve issues end to end across chat, email, SMS, WhatsApp, voice and ChatGPT, priced only on successful outcomes and free when the case escalates to a human. It is well capitalised ($1.585B raised, valued above $15B as of May 2026) and FedRAMP High certified as of June 2026, but every engagement runs through sales with no public price, no free tier and a gated SDK. The seven tools below are this site's other Published, individually researched support-agent listings, each earning its place for a specific reason. Decagon is the closest rival at the same enterprise, sales-led tier. Ada is the longest-established incumbent. Intercom Fin is the only one with a public per-resolution price and a free trial. Zendesk AI Agents brings the same per-resolution model into the largest installed helpdesk. Salesforce Agentforce is the free-to-start, metered enterprise option for Salesforce shops. ElevenLabs Conversational AI is the only entry whose first-class asset is voice quality. Crescendo replaces the platform with a fully-managed CX operation. Every fact below traces to each tool's own Published, already-sourced listing on this site.

| # | Name | What it is | Why it's here | Pricing | API |
| --- | --- | --- | --- | --- | --- |
| 1 | [Decagon](https://theagentsindex.com/decagon.md) | Enterprise AI customer service agents for chat, voice and email. $4.5B valuation, custom contracts, no public price. | The closest real rival. Both are enterprise, sales-led agent platforms with no self-serve tier, competing for the same large-account budget. Decagon is the more knowable of the two on price (Vendr median $386K/year across tracked contracts), publishes named case studies (Duolingo 80% deflection, ClassPass 95% cost reduction) and a third-party cost anchor Sierra's outcome rate lacks. Sierra reaches further on channels (inside ChatGPT itself), Decagon does not advertise that. | Custom | No |
| 2 | [Ada](https://theagentsindex.com/ada.md) | A Toronto-founded AI customer service agent platform from 2016. Sales-led, custom-quoted, with a Reasoning Engine, MCP server and a public V2 REST API that newer rivals in the category do not all publish. | The longest-established alternative, founded in 2016, eight years before Sierra. Ada has $190M+ raised and publishes a Conversations/Email API and an MCP server that most sales-led rivals here do not put on a public page. Still a sales-led process like Sierra, and a wide admin-versus-end-user satisfaction gap (4.6/5 on G2 from the teams who configure it, 2.0/5 on Trustpilot from the customers chatting with it) that Sierra's listing carries no equivalent public signal on either way. | Custom, contact sales | Yes |
| 3 | [Fin](https://theagentsindex.com/intercom-fin.md) | Intercom’s customer-service AI agent, resolves tickets omnichannel over any helpdesk, billed per resolution. | The only genuine self-serve option with a published per-resolution price ($0.99, with a 14-day free trial and no card). Fin is a layer on top of a helpdesk you already run rather than the omnichannel, action-taking agent OS Sierra builds for large enterprises, so the trade is breadth for transparency and a trial you can start today. | $0.99 / outcome | Yes |
| 4 | [Zendesk AI Agents](https://theagentsindex.com/zendesk-ai-agents.md) | The customer-facing AI agent built into Zendesk's Suite helpdesk, now with Forethought's autonomous engine bundled in, billed per Verified Resolution on top of a per-seat plan. | The same per-resolution model as Fin, bolted onto the largest installed helpdesk. $55/agent/month gets into Suite Team with the Essential AI Agent tier included; the per-Automated-Resolution meter above the plan allowance is now published at $1.50 committed or $2.00 pay-as-you-go. The trade against Sierra is that you are buying into the Zendesk suite and Forethought's engine rather than a standalone agent OS. | $19 / agent/month, billed annually | Yes |
| 5 | [Salesforce Agentforce](https://theagentsindex.com/salesforce-agentforce.md) | Salesforce's enterprise platform for building, testing and running AI agents across customer and employee workflows, with CRM actions, voice, APIs, MCP and multi-agent orchestration. | The only free-to-start enterprise option here. Salesforce Foundations is free and includes Agentforce Builder, Prompt Builder, Agent Script, Agentforce Coworker and Agentforce Vibes. Paid execution runs on Flex credits at $500 per 100,000 credits, Conversations at $2 per customer-facing conversation, or $5 to $550 per-user monthly add-ons. Flex credits and Conversations cannot be used in the same org. | Free | Yes |
| 6 | [ElevenLabs Conversational AI](https://theagentsindex.com/elevenlabs-conversational-ai.md) | The voice-quality specialist’s own agent layer, 10,000+ voices and instant cloning, with a bring-your-own-LLM brain. | The only entry whose primary asset is voice quality, 10,000+ voices with instant cloning, and a bring-your-own-LLM brain. Free plan starts at $0/month with 15 call minutes, paid tiers run $6 to $990/month, and over-plan minutes bill at $0.08/min ($0.16/min in burst). The underlying LLM and any external telephony are billed separately based on usage. | $0 / mo | Yes |
| 7 | [Crescendo](https://theagentsindex.com/crescendo.md) | Fully-managed, AI-native CX platform that replaces your entire support stack with agents, QA and human staffing, billed per resolved outcome. | Not a platform at all. Crescendo is a fully-managed outsourced CX operation (agents, QA, knowledge-base upkeep, staffing) billed per resolution from $2.99, for teams that do not want to configure software themselves the way Sierra's Agent Studio and Ghostwriter require. Every engagement starts with a proof-of-value pilot rather than Sierra's direct-to-contract sales process, but there is no API and no self-serve trial either way. | From $2.99 per resolution / per resolution | No |

## Methodology

Drawn from this site's own Published, individually-researched support-agents and agent-platforms categories. A tool qualifies only if its pricing model, pros, cons and best-for call are already fact-checked and sourced on its own listing. The order runs from the closest competitive rival to the furthest departure in buying model: Decagon first (the nearest enterprise head-to-head), Ada second (the longest-established sales-led incumbent), Intercom Fin third (the only self-serve option with a published per-resolution price), Zendesk AI Agents fourth (the same per-resolution model bolted onto the biggest installed helpdesk), Salesforce Agentforce fifth (the only free-to-start, metered enterprise option for Salesforce shops), ElevenLabs Conversational AI sixth (the only entry whose primary asset is voice quality), Crescendo seventh (a fully-managed CX service rather than software). Excluded eight Published peers that serve a different buyer: Cresta is augmentation rather than replacement and was dropped on that ground; Botpress, MindStudio, Relevance AI, Dify and others are generalist agent builders, not support-agent platforms.