Sierra for enterprise white-glove. Decagon for mid-market chat. Intercom Fin for outcome-based pricing inside Intercom. Parloa for voice contact centers. Vapi for developer-first builds.
This is the buyer's guide for AI customer service agents in 2026. We focus on five names that consistently deliver real deflection rates in production deployments.
The 30-second comparison
| Sierra | Decagon | Intercom Fin | Parloa | Vapi | |
|---|---|---|---|---|---|
| Best for | Enterprise branded CX | Mid-market chat | Inside Intercom | Voice contact centers | Developer-first |
| Pricing | $150–500K/yr | $40–120K/yr | $1/resolution | $0.50–2/call | $0.05/min PAYG |
| Channels | Voice + chat | Chat-first | Chat-first | Voice-first | Voice |
| Deflection | 70–80% | 65–75% | Pay only for what deflects | 50–65% voice | Variable (you build) |
| Setup time | 4–12 weeks white-glove | 2–6 weeks | 1–2 weeks | 4–8 weeks | DIY |
| Languages | 100+ | 95+ | 45+ | 12+ | LLM-dependent |
All five are autonomous agents — they take action without per-step human approval. See our autonomous vs copilot framing for the autonomy tier.
When each one wins
Pick Sierra for enterprise white-glove deployments
Sierra is the consensus choice for enterprise brands where the customer experience defines the company. Built by Bret Taylor and Clay Bavor; concierge onboarding; voice + chat parity; consistent brand persona across channels.
Strongest on:
- Brand voice consistency across thousands of conversations
- Multi-channel parity (same persona on voice, chat, email)
- Enterprise compliance (SOC 2, HIPAA, regional data residency)
Tradeoffs: enterprise pricing (six figures), multi-week deployment, sales-led — not a SaaS sign-up.
Pick Decagon for mid-market chat
Decagon is the pragmatic option for mid-market companies with strong helpdesk infrastructure (Zendesk, Intercom, Salesforce). Chat-first; 65–75% tier-1 deflection in mature deployments.
Pricing is typically per-resolution metered, $40–120K/year for most deployments. Sales-led but faster to deploy than Sierra.
Pick Intercom Fin if you're already on Intercom
Intercom Fin is the lowest-friction option for Intercom customers. $1 per resolved conversation — you pay only for what actually deflects. No subscription, no annual commit.
Strongest on:
- Existing Intercom workspaces (deepest integration)
- Outcome-based pricing transparency
- Quick deployment (1–2 weeks)
Tradeoffs: ecosystem lock-in (less appealing if you live in Zendesk), per-resolution math gets unpredictable at burst-traffic spikes.
Pick Parloa for voice contact centers
Parloa is the leader for AI voice agents in contact-center deployments. Latency under 800ms, 12+ languages with natural-sounding voices, deep telephony integration (Twilio, Vonage, Genesys).
Strongest on:
- Voice-first deployments (50%+ of contact volume is phone)
- Multi-language voice quality
- Human handoff (preserves transcript + intent)
Tradeoffs: voice-first means chat is a secondary channel. Sales-led pricing.
Pick Vapi for developer-first voice builds
Vapi is the developer's choice for voice agents. SDK-first, $0.05/minute pay-as-you-go, bring your own LLM provider.
Strongest on:
- Custom voice agents (you build the conversation logic)
- Cost transparency (per-minute math, no surprise contracts)
- Provider flexibility (Anthropic, OpenAI, your private endpoint)
Tradeoffs: you build the product, not a turnkey deployment. Best for engineering-led organizations.
A practical decision tree
1. What's your support volume?
- Under 1,000 tickets/mo → maybe just chatbot + good KB (see AI agent vs chatbot)
- 1,000–5,000/mo → Intercom Fin (if you use Intercom) or Decagon
- 5,000+/mo → Decagon, Sierra, or Parloa depending on channel mix
2. What's your primary channel?
- Chat-heavy → Decagon or Intercom Fin
- Voice-heavy → Parloa or Vapi
- Multi-channel parity → Sierra (only one with true parity)
3. What's your buying motion?
- Self-serve / no procurement appetite → Intercom Fin or Vapi
- Mid-market sales OK → Decagon
- Enterprise sales required → Sierra
- Build it yourself → Vapi
Pricing reality (numbers worth knowing)
Real deployment costs from public sources + customer interviews:
| Tier | Volume | Annual cost | Per-resolution cost |
|---|---|---|---|
| Intercom Fin entry | 1K resolutions/mo | $12K | $1.00 |
| Decagon growth | 10K tickets/mo | $50–80K | $0.40–0.65 |
| Sierra mid | 50K tickets/mo | $150–250K | $0.25–0.40 |
| Sierra enterprise | 200K tickets/mo | $300–500K | $0.10–0.25 |
| Parloa voice | 50K calls/mo | $60–120K | $0.10–0.20/call |
Per-resolution math beats per-seat math at any meaningful volume. Five human reps fully loaded cost $200–400K/year and resolve 12–25K tickets/year combined — about $10–30 per resolution.
Setup time: what to plan for
The biggest variable in deployment time is knowledge base maturity, not agent vendor.
- KB is well-tagged, version-controlled, source-of-truth: deploy in 2–4 weeks
- KB is scattered across Notion, Confluence, internal docs, tribal: 8–16 weeks of cleanup before the agent gets useful
- KB doesn't exist yet: build the KB first, then deploy
This is true regardless of which vendor you pick. Sierra's white-glove team will sometimes help with KB cleanup; the rest don't.
What to evaluate during procurement
Don't fixate on demo flash. The actual procurement checklist:
- Deflection rate on YOUR data — every vendor will demo a 75% deflection rate. Test on 100 of your real tickets.
- Integration depth — what does it actually call in your stack? Salesforce records, order DB, refund flow, account merge?
- Failover quality — what happens when the agent can't help? Speed of escalation, completeness of context handed to the human.
- Cost predictability — model worst-case month at burst traffic.
- Auditability — can you replay any conversation? See exactly which tools were called?
The verdict
For most teams in 2026:
- Enterprise with brand-critical CX → Sierra
- Mid-market on Zendesk / Intercom / Salesforce → Decagon
- Already on Intercom, want low-friction start → Intercom Fin
- Voice-first contact center → Parloa
- Engineering-led, build your own → Vapi
For the broader category browse /category/support or our customer support agent buyer's guide for the longer treatment.