Forrester Wave Leader 2026 — enterprise voice and chat agent platform (now NiCE Cognigy).
ツール利用音声メモリRAG
Cresta vs Sierrawhich AI support agent should you pick in 2026?
Conversational AI agent assist for contact centers — coaches reps and automates after-call work in real time.
VoiceTool useMemoryRAG
Cresta vs Sierra — specs
| Spec | Cresta | Sierra |
|---|---|---|
| Agent Rank | 80 / 100 (A) | 78 / 100 (A) |
| Autonomy | Semi-autonomous | Autonomous |
| Pricing | Subscription · Free tier | Subscription · Free tier |
| Open source | No | No |
| Capabilities | Voice, Tool use, Memory, RAG | Voice, Tool use, Memory, RAG |
| Integrations | 4 apps | 3 apps |
| Verified | Verified | Verified |
| Released | Mar 2025 | Feb 2025 |
Agent Rank breakdown
Cresta
Agent Rank
80/ 100
- 自律性
- 8
- 機能
- 8
- 連携
- 8
- 料金
- 9
- 完成度
- 5
- 検証性
- 10
自律性、機能、連携、料金、成熟度、編集部の検証を基に自動算出。デプロイごとに更新されます。 どのように算出されているか?
Sierra
Agent Rank
78/ 100
- 自律性
- 9
- 機能
- 8
- 連携
- 6
- 料金
- 9
- 完成度
- 5
- 検証性
- 10
自律性、機能、連携、料金、成熟度、編集部の検証を基に自動算出。デプロイごとに更新されます。 どのように算出されているか?
Pros & cons
Cresta
メリット
- +Best-in-class real-time coaching — recommendations during the call
- +Auto-summarizes calls + drafts after-call work, saving reps 5+ min per call
- +Strong deployments at Fortune 500 contact centers
デメリット
- −Enterprise-only — minimum seat counts in the hundreds
- −Implementation requires conversation-data training (4–8 weeks)
- −Augments humans rather than replacing them — different positioning than fully autonomous tier
Sierra
メリット
- +Best-in-class for branded customer-facing agents (voice + chat parity)
- +Concierge onboarding from one of the strongest teams in AI
- +Indistinguishable-from-human quality in tier-1 deployments
デメリット
- −Enterprise-only pricing — typical contracts $150–500k/year
- −Deployment is white-glove, not SaaS — multi-week setup
- −Overkill for SMB or mid-market support volumes
Pricing
Cresta
Enterprise
カスタム
Contact centers 200+ reps
- +Real-time agent assist
- +Conversation intelligence
- +After-call work automation
Sierra
おすすめ
Branded agent
カスタム
Enterprise
- +Voice + chat
- +Custom persona
- +White-glove implementation
- +SOC 2 II + HIPAA option
Which one should you pick?
Sierra
Pick Sierra if you want the highest autonomy and the verification loop is in place.
Try Sierra →Affiliate links. We may earn a commission at no extra cost to you.
Frequently asked
Should I pick Cresta or Sierra in 2026?+
Pick Cresta if its specific capabilities (Voice, Tool use) match what you need. Pick Sierra if you want the highest autonomy and the verification loop is in place. Most working teams running both can use Cresta for primary work and Sierra for the workflows where its specific strengths matter.
What's the price difference between Cresta and Sierra?+
Both Cresta and Sierra start in the same pricing range (Subscription · Free tier vs Subscription · Free tier). Total cost of ownership depends on your team size and volume — see the TCO calculator for your specific math.
Which is more autonomous, Cresta or Sierra?+
Sierra is the more autonomous of the two (Autonomous vs Semi-autonomous). Higher autonomy ships throughput faster but requires verification loops in place — see our autonomous-vs-copilot framing for when each tier wins.
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See more alternatives: alternatives to Cresta · alternatives to Sierra
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