9 best Sierra AI alternatives for AI customer support in 2026

The strongest Sierra AI alternatives in October 2026 are Robylon for an AI agent that takes action across email, chat, voice and WhatsApp with published prices and a free plan; Decagon for enterprises that want a sales-led voice and chat platform like Sierra’s; Fin and Salesforce Agentforce for teams already on Salesforce; and Ada for CX teams that want to run the agent themselves. Kore.ai and Cognigy suit large contact centers that want AI agents built around their telephony and contact center platforms. Zendesk and Gorgias cover teams staying on Zendesk and Shopify stores.

Sierra is a capable enterprise AI agent: it answers and acts in systems of record, covers voice and messaging in 59 languages, and holds certifications few vendors match. Teams evaluating it look elsewhere when they need a published price, a way to start without a sales contract, or an agent that runs inside the helpdesk their human team already uses. Every tool below is judged on three things: whether the agent takes the action a ticket needs, whether every channel runs from one setup, and whether it fits the stack you already run.

Sierra AI alternatives at a glance

Prices checked October 2026 on each vendor's pricing page. G2 ratings read October 2026, with the review count in brackets.

Robylon publishes this page and ranks itself first; every tool on the list, Robylon included, gets the same “Where it falls short” line.

What Sierra does

Sierra is an AI agent platform for large enterprises, founded by Bret Taylor and Clay Bavor and launched in February 2024. Its agents answer customers and take actions in systems of record, including returns, insurance claims and mortgage origination, over voice, chat, WhatsApp, Apple Business Chat, SMS, email and a ChatGPT app, in 59 languages. Teams build agents in Agent Studio without code or by prompting Ghostwriter with their procedures, alongside Sierra’s own agent development team. Sierra bills per outcome under contracts agreed with each customer and publishes no prices. It holds FedRAMP High and PCI DSS Level 1, and says it works with almost half of the Fortune 50.

Why teams look beyond Sierra

No published price

Sierra prices per outcome and agrees what counts as an outcome in each contract, according to its outcome-based pricing post. sierra.ai has no pricing page as of October 2026, so a team cannot estimate its bill before a sales process, or compare it with a tool that publishes a rate.

Sales-led access only

There is no free plan, free trial or self-serve signup. Access starts with a demo request, and the documentation at docs.sierra.ai is behind a login. A team that wants to test an agent on its own tickets this week, rather than this quarter, has no way in.

Built for the largest enterprises

Sierra says half of the companies using it have revenue over $1 billion and a fifth over $10 billion. Its contracts, deployment model and certifications are shaped for that scale. A mid-market team pays for a process and a compliance scope it may not need.

In front of the contact center

Sierra’s agent sits in front of the existing contact center and routes conversations to the human care team through partners that include Amazon Connect, Five9, Genesys and Twilio. Sierra’s public pages show no human-agent inbox of its own. A support team that works in a helpdesk such as Freshdesk or Zendesk looks for an agent that runs inside it.

Capabilities hard to check upfront

With docs behind a login and no public price, most of what a buyer can verify before talking to sales comes from Sierra’s product pages and blog. Teams that shortlist on documented capabilities and published limits find less to compare.

Four kinds of Sierra alternatives

Four kinds of product get called Sierra alternatives, and they solve different problems.

• AI agent platforms: an agent that answers and resolves across channels, standalone or alongside a helpdesk. Robylon, Decagon, Fin and Ada belong here. All four take actions in other systems; Robylon and Fin also run inside existing helpdesks, while Decagon and Ada hand conversations to one.
• Contact center AI platforms: AI agents built for large contact centers, with their own voice gateways, deterministic flows next to generative ones, and handover into contact center platforms. Kore.ai and Cognigy belong here. Both take actions in other systems and both hand over to Genesys Cloud and Salesforce Service Cloud; Kore.ai also sells its own contact center.
• Helpdesk and CRM suites with their own AI agent: ticketing, inbox and reporting for a human team, with an AI agent added and billed on top. Zendesk and Salesforce Agentforce belong here. Their agents run only inside their own helpdesk or CRM.
• E-commerce support tools: a helpdesk and AI agent built around the store. Gorgias belongs here, with AI Agent actions on Shopify orders.

The right kind depends on where your human team works and how you want to buy. If you want Sierra’s enterprise model with a different vendor, the first two kinds fit. If you want published prices or the agent inside your current helpdesk, Robylon, Fin and the suites fit.

How we compared the tools

We read each vendor’s pricing page, help centre or docs, product pages and trust page on 7 October 2026, and each tool’s G2 page the same day. Where a vendor publishes no price, the table says so rather than estimating one. We did not run hands-on tests for this page.

We compared them on what the AI agent can resolve, channels covered, where each runs, billing model, setup effort, and how each works for support agents and team leads.

The 9 best Sierra AI alternatives

1. Robylon

Best for: support teams that want an AI agent to resolve tickets end to end, taking actions in other systems, on every channel from one setup, with published prices.

What it is for: Robylon is an AI customer support platform that resolves tickets across email, chat, voice and WhatsApp. It works standalone or alongside an existing helpdesk. It takes the action a ticket needs: agents read the systems the answer lives in, including orders, accounts and bookings, act through tools built from your APIs and connected apps, and hand anything they cannot finish to a person with the checking already done. Every channel runs from one setup, sharing the same agents, knowledge base and analytics. And it fits the stack you already run, inside the helpdesk your team uses or standalone with its own inbox. A US logistics enterprise cut its query resolution time by 95% with Robylon.

What the AI does:

• A triage agent routes each conversation to the sub-agent for that topic, so refunds, order status and account changes each follow their own instructions.
• Agents call tools built from your APIs and from 32 pre-built integrations, among them Shopify, HubSpot, Salesforce and Google Sheets, to look up an order, issue a refund or update an account. Custom API integrations are on the Business plan.
• The knowledge base answers from your sources, and the KB gap report shows the questions it could not answer (Pro plan and above).
• Anything the agent cannot finish goes to a person with the conversation, intent and checks attached.
• Evaluations and bulk knowledge base testing score answers before and after a change, and version history restores an earlier version of an agent.
• Teams choose the AI model per agent from the models Robylon supports, and a failed model call retries on a backup model.

Channels: email, website and in-app chat, voice, WhatsApp, Instagram, Facebook, SMS through Twilio, YouTube comments, and reviews on Google Play, the App Store and Google My Business, all listed on the channels page. Robylon runs standalone with its own inbox and optional human seats, or inside Freshdesk, Zendesk, Zoho Desk, Salesforce, Vtiger, Intercom, Freshchat, SalesIQ and Gorgias. WhatsApp and email start on the Pro plan; voice phone calls and the Freshdesk, Zendesk, Zoho Desk, Intercom, Freshchat and Gorgias integrations start on Business.

Pricing: by AI credits rather than per outcome (see pricing). The Starter plan is free with 300 credits a month (about 40 conversations), paid plans start at $25 a month for 500 credits, Business starts at $180 a month, and yearly billing takes 10% off. Seats for a human team are optional, at $19 to $89 per seat a month. G2 rating: 5.0 from 42 reviews (G2, October 2026).

Where it falls short: voice phone calls start on the Business plan at $180 a month, and Robylon publishes no per-minute voice price. Credits per conversation vary with the AI model chosen, so the monthly bill is harder to forecast than an agreed price per outcome. Plan changes go through an account manager, because self-serve billing is not live yet.

Where Sierra does better:

• Compliance scope: Sierra holds FedRAMP High, PCI DSS Level 1, ISO 27001, ISO 42001, AIUC-1 and CSA STAR alongside SOC 2 Type II and HIPAA. Robylon’s site shows SOC 2 Type II, GDPR, HIPAA and CPRA/CCPA.
• Payments in conversation: Sierra takes PCI-compliant card payments in voice and chat.
• Billing on handover: an escalated case usually carries no charge under Sierra’s outcome pricing. Robylon spends credits on every conversation, resolved or not.
• Enterprise track record: Sierra reports $100 million in annual recurring revenue (November 2025) and almost half of the Fortune 50 as customers.
• Languages: 59 on Sierra’s product page, against Robylon’s over 40.
• Channels: Apple Business Chat and a ChatGPT app, neither of which is on Robylon’s channel list.

Pick it if: you want an AI agent that takes actions across email, chat, voice and WhatsApp, with prices you can read today and a free plan to start, inside the helpdesk you keep or standalone. Choose Sierra if you are a large enterprise that needs FedRAMP High or PCI DSS Level 1 from the AI vendor and wants Sierra’s team to build the agent with you.

2. Decagon: best for enterprise voice

Best for: enterprise support and CX teams that buy through sales and want voice and chat agents built from written procedures.

Decagon’s agents follow Agent Operating Procedures, instructions written in natural language that verify identity, issue refunds and take payments in connected systems. Duet drafts, tests and refines those procedures, and Decagon Assist, launched on 19 August 2026, gives human reps summaries, replies and actions inside Salesforce, Zendesk and Front. Decagon offers single-tenant, customer-VPC and on-premises deployment as well as standard SaaS. It raised $250 million at a $4.5 billion valuation in January 2026.

What the AI does: answers and takes actions in connected systems through pre-built connectors, APIs, MCP and SIP trunking, with no published plan tiers.

Channels: voice (inbound and outbound), web chat, mobile app chat, SMS, WhatsApp, email, and a gateway for customers’ own AI agents. Voice supports more than 70 languages.

Pricing: per conversation or per resolution, quote only (Decagon’s pricing explainer). Per-resolution pricing charges nothing for escalations; per-conversation pricing, which Decagon says most customers choose, charges every incoming conversation. G2: 4.8 from 29 reviews (G2, October 2026).

Where it falls short: no public price, free plan or self-serve signup, and documentation behind a login, so it shares Sierra’s buying process. Escalations go to the team’s existing helpdesk; Decagon’s public pages show no human inbox of its own.

Pick it if: you want Sierra’s enterprise model from another vendor, with more voice languages and deployment in your own cloud or on premises.

3. Fin: best without a sales contract

Best for: support teams that want a per-outcome AI agent they can start on a trial, on the Intercom helpdesk or on top of another one.

Fin, formerly Intercom Fin, answers from your knowledge sources and takes actions through Procedures, plain-language instructions that call any REST API or MCP connector. It runs on Intercom’s own helpdesk, or on top of Salesforce Service Cloud, HubSpot, Freshdesk and other helpdesks. Salesforce completed its acquisition of Fin on 10 September 2026, so Fin and Agentforce now share an owner.

What the AI does: answers and takes actions through Procedures and data connectors; Fin bills at most one outcome per conversation.

Channels: chat, email, WhatsApp, SMS and social messaging; Fin Voice is sold to select customers through sales.

Pricing: $0.99 per outcome, with nothing charged when the customer asks for a person or Fin cannot answer. On the Intercom helpdesk, seats start at $85 a month billed annually (Advanced); on another helpdesk there is a 50-outcome monthly minimum (Fin pricing). G2: 4.5 from 3,918 reviews (G2, October 2026).

Where it falls short: voice is not sold on published terms, and the per-outcome bill rises in step with every resolution, so cost grows at the same rate as volume.

Pick it if: you want to start on a 14-day trial and pay a published price per outcome instead of negotiating a contract.

4. Ada: best for self-managed CX

Best for: enterprise CX teams that want to manage the AI agent themselves, without engineering.

Ada runs one Reasoning Engine across chat, email, voice and social, with Playbooks and Processes for multi-step workflows and Coaching to tune answers. Ada Computer, launched on 24 September 2026, lets the agent act through API tools, sandboxed Python code tools and MCP tools, and PII and PHI redaction is built in. Ada hands conversations to the team’s own helpdesk or contact center, including Zendesk, Salesforce, Genesys, NICE CXone and Amazon Connect.

What the AI does: answers from Knowledge in 60 languages for chat and email and takes actions through Ada Computer tools.

Channels: web chat, in-app chat, voice, email and Instagram Direct natively; WhatsApp, Facebook Messenger, X DMs and SMS through Zendesk Sunshine Conversations. Voice supports 42 languages.

Pricing: per conversation for most customers, with a resolution-based model for some enterprises; quote only (Ada platform). G2: 4.6 from 174 reviews (G2, October 2026).

Where it falls short: under per-conversation pricing a handed-over conversation is still billed, and WhatsApp, Messenger and SMS depend on Zendesk Sunshine Conversations rather than a native connection.

Pick it if: your CX team wants to own the agent’s training and workflows and can buy through sales.

5. Salesforce Agentforce: best for Service Cloud

Best for: mid-market and enterprise service teams that already run Salesforce Service Cloud.

Agentforce answers from Salesforce Knowledge and Data 360 and acts through standard and custom actions built with Flows, Apex, prompts and MuleSoft API connectors. Casey, the help agent, schedules appointments, manages orders and escalates to a rep with full context. Like Sierra, it suits large organisations, but it lives inside the CRM instead of in front of the contact center.

What the AI does: answers and takes actions inside Salesforce and connected systems; Agentforce Voice updates records and creates cases on calls, in English (US, UK and Australia) as of October 2026.

Channels: web chat, in-app, help sites and portals, SMS, WhatsApp, Facebook Messenger, Apple Messages for Business, LINE and voice.

Pricing: $2 per conversation, $2 per resolution for Casey, or Flex Credits at $500 per 100,000 credits. Service Cloud Core, the first edition that runs Agentforce, costs $195 per user a month billed annually (Agentforce pricing). G2: 4.3 from 1,696 reviews (G2, October 2026).

Where it falls short: it runs inside Salesforce Service Cloud only, and chat handovers need Contact Center Digital at $75 per user a month on top of the Core seat.

Pick it if: your service team already lives in Salesforce and wants published per-conversation prices from the CRM vendor.

6. Kore.ai: best for full contact centers

Best for: large enterprises in regulated industries that want AI agents, a contact center and quality scoring from one vendor.

Kore.ai’s customer service line, AI for Service, runs on the Kore.ai Agent Platform, whose Artemis edition launched on 21 May 2026. Agents are written in Agent Blueprint Language or generated by the Arch AI architect from a plain-language description, and they mix LLM reasoning with deterministic flows while policies are enforced outside the model. Kore.ai also sells its own contact center, Contact Center AI, with agent and supervisor desktops, routing and workforce management; Agent AI coaches human reps and Quality AI scores every voice and chat conversation. Its launch release lists SOC 2 Type II, ISO 27001, PCI DSS, FedRAMP Moderate, HITRUST and GDPR, and Kore.ai says it serves 500+ Global 2000 organisations.

What the AI does: answers and takes actions in customer systems, among them updating accounts, scheduling appointments and setting up autopay, through prebuilt integrations with Salesforce, Microsoft Dynamics 365, HubSpot, ServiceNow, Zendesk, Shopify and Stripe, plus HTTP, code and MCP tools.

Channels: voice through Kore.ai’s own voice gateway or your SIP telephony, web and mobile chat, email, WhatsApp, Facebook Messenger, Instagram, LINE, Telegram, Slack and Microsoft Teams; SMS through Twilio. Agents hand off to Kore.ai’s contact center, Salesforce Service Cloud, Genesys Cloud, ServiceNow or Five9.

Pricing: AI agents are billed per 15-minute session of conversation, so a 31-minute conversation is 3 sessions, and contact center seats per agent; no rates are published, and kore.ai/pricing returns a not-found page (Kore.ai billing docs). G2: 4.6 from 505 reviews (G2, October 2026).

Where it falls short: no published rates, and the free tier of the new platform is open only to approved email domains. Two product generations and their plan sets coexist during a rebrand as of October 2026, so a quote has to say which one it covers.

Pick it if: you want AI agents and the contact center behind them from one vendor, with FedRAMP Moderate and self-hosted deployment available.

7. Cognigy: best for CCaaS contact centers

Best for: large enterprise contact centers, many on NiCE CXone or Genesys, that want AI agents in front of the contact center they already run.

Cognigy has been owned by NICE since 8 September 2025 and is sold on its own or inside NiCE CXone. Its AI agents are given Jobs with Tools that call APIs, retrieve data, start workflows and hand over to people, and LLM-driven agents can be mixed with deterministic flows in one conversation. Teams choose models from OpenAI, Anthropic, Google or AWS, or a privately hosted one, with fallback between them. Named customers include Lufthansa Group, Toyota, DHL and Mercedes-Benz.

What the AI does: answers and takes actions in other systems, among them authentication, payments, bookings and record updates, through 110+ prebuilt tools and integrations plus MCP. Knowledge AI (answers from documents) is licensed separately, and Agent Copilot assists human agents on voice and chat.

Channels: web chat, voice over SIP through Cognigy Voice Gateway, WhatsApp, Facebook Messenger, LINE, Microsoft Teams and Slack; SMS through Twilio. Conversations hand over to NiCE CXone, Genesys Cloud, Salesforce Service Cloud, RingCentral Engage or 8x8.

Pricing: per billable conversation, counted as up to 50 user inputs in 24 hours, with voice billed by concurrent lines through Voice Gateway; quote only, and cognigy.com/pricing returns a not-found page (Cognigy billing docs). G2: 4.6 from 13 reviews (G2, October 2026).

Where it falls short: an escalated conversation is still billed, because human-agent turns that flow through Cognigy count. Voice Gateway, Knowledge AI and Ops Center each need their own licence, and Cognigy’s own agent workspace, Live Agent, is in maintenance mode, so the human team needs a contact center platform.

Pick it if: your contact center runs on NiCE CXone or Genesys and you want enterprise AI agents that mix generative answers with fixed, auditable flows.

8. Zendesk: best for Zendesk teams

Best for: support teams that run, or plan to run, the Zendesk helpdesk and want its own AI agent.

Since a rollout in May and June 2026, Zendesk’s AI agents are on every Suite and Support plan, built from natural-language procedures with actions that read and write data in external systems. Each agent serves one channel type: messaging, email or voice. Voice AI agents became generally available in September 2026.

What the AI does: answers and takes actions through integrations, replying in more than 80 languages.

Channels: email, web form, web messaging and live chat, mobile SDKs, voice (Zendesk Talk), WhatsApp, Facebook Messenger, Instagram, X DMs, LINE, WeChat and Slack; SMS through the Text add-on.

Pricing: $1.50 per committed automated resolution or $2.00 pay-as-you-go, on top of seats from $19 per agent a month billed annually (Support Team) or $55 (Suite Team) (Zendesk pricing). G2: 4.3 from 7,093 reviews (G2, October 2026).

Where it falls short: two billing models run at once, and the newer resolution allowances introduced on 18 May 2026 have unpublished tier prices. The AI agent works only inside Zendesk.

Pick it if: you are staying on Zendesk and want the AI agent from the same vendor as the helpdesk, on published prices.

9. Gorgias: best for Shopify stores

Best for: Shopify brands that want a helpdesk and AI agent built around the store.

Gorgias AI Agent answers from the help center, website, documents and Shopify data. On Basic and above it takes Shopify actions with no extra setup: cancel an unfulfilled order with a refund and restock, edit a shipping address, remove or replace items, reship an order and add an order note. App Actions extend it to Loop Returns, Recharge, ShipStation and other store apps.

What the AI does: answers and acts on Shopify orders and connected store apps; it needs a connected Shopify store.

Channels: email, chat, help center, contact forms, Facebook Messenger, Instagram and WhatsApp; voice and SMS through paid add-ons. AI Agent on WhatsApp, Instagram and Messenger is in open beta as of October 2026.

Pricing: $0.90 per automated interaction on annual plans or $1.00 monthly, and each AI-resolved ticket also carries the helpdesk ticket fee; plans start at $10 a month for 50 tickets (Gorgias pricing). G2: 4.6 from 582 reviews (G2, October 2026).

Where it falls short: AI Agent works only for Shopify stores and only inside Gorgias’s own helpdesk, and an AI-resolved ticket is billed twice, as a ticket and as an automated interaction.

Pick it if: you run a Shopify store and want order actions handled inside a store-focused helpdesk.

Alternatives by situation

What to decide before switching

Actions versus answers

Count what share of your tickets need the agent to act in another system, such as a refund, an order change or a booking, rather than answer from help content. Every tool on this list takes actions, but they reach your systems differently: Robylon, Fin, Decagon and Ada through APIs and connectors, Agentforce through Salesforce Flows, and Gorgias through Shopify.

Channels your customers use

List the channels your customers actually use today, including voice. Voice narrows the field: Decagon and Sierra lead on languages, Agentforce Voice is English only as of October 2026, Fin sells voice through sales, Gorgias sells it as an add-on, and Robylon includes voice phone calls from its Business plan.

Where your team works

Decide whether your human team stays in its current helpdesk or contact center. A team in Freshdesk, Zendesk, Zoho Desk, Intercom or Salesforce can keep it with Robylon. A contact center on NiCE CXone or Genesys Cloud can keep its platform with Cognigy or Kore.ai, or move to Kore.ai’s own contact center. A team changing helpdesk anyway can take Zendesk or Gorgias, which replace both at once.

Pricing at your volume

Sierra, Decagon and Ada publish no prices, so compare published options at your own volume and treat the rest as quotes. On published prices for 3,000 chat and email conversations a month, 60% resolved by the AI (1,800 resolutions), 3 human agents and monthly billing:

Robylon’s figure is 3,000 conversations at about 7.5 credits each (22,500 credits): the Business 10,000-credit tier at $300 plus 13 extra 1,000-credit bundles at $25, and 3 Basic seats at $19. Agentforce publishes yearly prices only: on annual billing, Casey at $2 per resolution with 3 Service Cloud Core plus Contact Center Digital seats comes to about $4,410 a month. Kore.ai bills its AI agents per 15-minute session and Cognigy per conversation of up to 50 inputs, but neither publishes a rate.

When to stay on Sierra

• Your security review requires FedRAMP High, PCI DSS Level 1 or AIUC-1 certification from the AI vendor.
• You take card payments inside voice or chat conversations and need the AI vendor to be PCI compliant for them.
• You want the vendor’s own agent development team to design and build the agent with you.
• You want to pay per agreed outcome, with escalated cases usually not charged.
• Your agents already run in production on Sierra, and rebuilding the procedures and integrations elsewhere would take months.

What usually drives a switch is the buying model rather than the agent: no published price, no way to start without a contract, or a team that works in a helpdesk Sierra does not run inside. If none of those applies, Sierra is a strong place to stay.

Moving off Sierra

1. Baseline the current numbers: resolution rate, CSAT, billed outcomes and cost per resolved conversation.
2. Export the procedures, knowledge sources and integration list behind each live Sierra agent.
3. Decide where your human team works after the move: the current contact center, a helpdesk, or the new vendor’s inbox.
4. Connect the systems the agent must act in: order management, billing, CRM and booking.
5. Build the top intents first and test them in bulk against real past conversations.
6. Run the new agent on one channel or one queue while Sierra handles the rest.
7. Compare resolution rate, CSAT and cost per resolution against the baseline, then move the remaining channels.
8. Keep Sierra available until the contract term ends in case you need to roll back.

Choosing a Sierra alternative

Sierra is one of the strongest enterprise AI agents available: it acts in systems of record, covers voice and messaging in 59 languages, and holds FedRAMP High and PCI DSS Level 1. For a large, regulated enterprise that wants the vendor to build the agent alongside its team, it remains a sound choice.

Move when the buying model stops fitting: no published price, no way to start without a contract, or a team that works in a helpdesk Sierra does not run inside. Decagon and Ada suit enterprises that want the same model from another vendor, Agentforce and Fin suit Salesforce teams, and Zendesk and Gorgias suit teams staying on those tools. Robylon suits teams that want the agent to take the action a ticket needs, run every channel from one setup and fit the stack they already run, and its Starter plan is free to try.