Sierra vs Decagon (2026)
Last updated: November 9, 2026
Answer in brief: Sierra and Decagon are the two enterprise platforms large brands most often shortlist for autonomous support. Both are sold through sales, and neither publishes a rate card. Choose Sierra if trust is the deal-breaker. It prices by outcome, wraps its LLMs in supervisor models, masks PII automatically, holds PCI DSS Level 1 certification for payments, and lists HIPAA, FedRAMP High and ISO 42001 compliance. Choose Decagon if speed of iteration wins. Its Agent Operating Procedures (AOPs) are written in natural language and owned by your CX team, engineers get Git-based versioning, and you can choose per-conversation or per-resolution pricing.
Top pick: Sierra for regulated, payment-heavy consumer brands that want to pay only for results.
Want your CX team rewriting agent logic weekly?
This is independent research from Sierra's and Decagon's own websites and published articles, read November 9, 2026. We did not test either product hands-on. Every result figure quoted here is vendor-reported. See the full ranked list.
Head to head
| Sierra | Decagon | |
|---|---|---|
| Pricing model | Outcome-based; may blend in per-conversation charges for routing or greeter interactions | Per conversation or per resolution; Decagon says most customers choose per conversation |
| Public rates | None | None |
| How you build | Ghostwriter builds agents from SOPs, transcripts, whiteboard photos, audio or plain English; Agent Studio is no-code | Natural-language AOPs, auto-generated from transcripts; Duet helps iterate |
| Guardrails | Supervisor models, deterministic access to systems of record, PII masking, topic and keyword filters | AOP rules for brand voice, escalations and hallucinations across channels |
| Testing | Multivariate Experiments, Monitors, Explorer deep research | Simulation testing, live A/B Experiments, Watchtower always-on QA |
| Observability | Every tool call, knowledge lookup and latency | Reasoning traces with runtime and latency |
| Compliance listed | SOC 2, HIPAA, GDPR, PCI, FedRAMP High, CCPA, CSA STAR, ISO 27001, ISO 42001 | Details in the Decagon Trust Center |
| Text channels | Chat, email, SMS, WhatsApp, ChatGPT (plus voice); 58 languages | Chat and email on one intelligence layer (plus voice) |
| Customers named | Rocket Mortgage, SiriusXM, ADT, CarMax, SoFi, Redfin | Chime, Duolingo, Notion, Hertz, Rippling |
Paying for a job well done vs paying per conversation
Sierra's pitch is simple: you pay when the agent delivers an outcome you agreed on upfront. Its pricing article lists resolved support conversations, saved cancellations, upsells and purchases as examples. Unresolved conversations generally aren't charged, though Sierra says routing or greeter interactions can be billed per conversation. Decagon offers both models: a fixed rate for every incoming conversation, or a higher fixed rate per resolved conversation with no charge for escalations. Both pricing articles date from December 2024 and were still live on the vendors' sites in November 2026. Per-conversation pricing is the easiest to forecast. Outcome pricing keeps the vendor tied to your resolution rate.
Who owns the agent's logic
Decagon built its product around AOPs. You write workflows the way you'd train a human on an SOP, and they combine the flexibility of natural language with the reliability of code. CX teams change behavior without waiting on an engineering sprint, while engineers keep Git-based version control. Sierra's Ghostwriter goes a step further on input: upload SOPs, transcripts or even whiteboard photos and audio, and it drafts a production-ready, multilingual agent with guardrails built in. It then suggests updates based on flagged issues, and you review each change before it ships.
Guardrails: wrapped models vs written rules
Sierra puts its controls in the architecture. Supervisor layers sit around the LLMs to reduce hallucinations and block abuse, and calls into your systems of record are deterministic. Cardholder data runs on separate PCI-certified infrastructure that never touches Sierra's LLMs. If one LLM provider has an outage, Sierra switches to another automatically. Decagon puts its controls in the procedures: you set rules for brand voice, escalation and hallucinations right in the AOPs, then trace any decision the agent made, step by step.
Proof before you scale
Both let you test before customers see changes. Decagon runs simulations at scale, live A/B experiments and Watchtower, which provides always-on QA. Its Chime case study reports 70% chat and voice resolution (vendor-reported). Sierra runs multivariate experiments, proactive monitors and Explorer, which does deep research on conversations. Ask both for a pilot on your own ticket mix and define what counts as resolved before you sign.
When to pick which
- Pick Sierra for financial services, healthcare, telecom or any brand that takes payments in conversation and needs FedRAMP High, HIPAA or PCI DSS Level 1 on the vendor's list.
- Pick Decagon if your CX operations team wants to own and edit workflows directly, and you prefer predictable per-conversation billing.
- Pick neither if you need a self-serve start this month; see Intercom Fin vs Decagon.
Voice is a big part of both platforms. For phone-first buying, see best AI phone agent. For the broader enterprise agent platform market, see enterprise agent platforms.
FAQ
Do Sierra or Decagon publish prices?
No. Both quote through sales. Sierra describes outcome-based pricing; Decagon offers per-conversation or per-resolution pricing.
Which is better for regulated industries?
Sierra publishes the longer compliance list: SOC 2, HIPAA, GDPR, PCI, FedRAMP High, CCPA, CSA STAR, ISO 27001 and ISO 42001, plus PCI DSS Level 1 for payments. Check Decagon's Trust Center for its current certifications.
Can non-engineers change the agent?
Yes, on both. Decagon's AOPs are written in natural language, and Sierra's Agent Studio and Ghostwriter let CX teams build and update agents without writing code.
Read next
Sierra review · Decagon review · Alternatives to Intercom Fin · How to choose · The ranked list
Sources
- Sierra
- Sierra trust and reliability
- Sierra: outcome-based pricing for AI agents (Dec 2024)
- Decagon
- Decagon Agent Operating Procedures
- Decagon: pricing the AI agent economy (Dec 2024)
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