Decagon.ai vs. Sierra.ai vs. Crescendo.ai | 2025 Edition

If you are exploring AI to expand your customer support, you are not alone. Choosing between Decagon.ai, Sierra.ai, and Crescendo.ai is not a simple decision. Implementing an AI support platform requires significant time, money, and effort. Making the wrong choice can lead to high switching costs and operational disruption down the road. That’s why we’ve broken down the key differences between Decagon.ai, Sierra.ai, and Crescendo.ai. This guide is designed to help you make an informed and confident decision from the start.

Decagon.ai, Sierra.ai, Crescendo.ai: Similarities

All three platforms are solid picks for omnichannel AI support agents, giving you 24/7 channel coverage. Before exploring the differences, let’s talk about some similarities among Decagon.ai, Sierra.ai, and Crescendo.ai.

1. Channel coverage: They all offer omnichannel support through chat, voice, email, and SMS. 
2. Natural responses: All three have AI support agents that make conversations sound natural, human-like, and empathetic.
3. High efficiency: All three have AI support agents that are capable of handling customer queries 24/7 in multiple languages, 10x faster than real-human agents. 
4. Seamless handoffs: They all preserve full conversational context during human handoffs, so human agents can pick up where the AI left off without asking customers to repeat themselves.

Decagon.ai vs Sierra.ai vs Crescendo.ai: What’s the Difference? 

TL;DR? Here is a quick breakdown of the key differences in capabilities of Sierra.ai, Decagon.ai, and Crescendo.ai. 

Detailed Overview

Once these three are up and running, they function pretty similarly, but they each have their own twist, especially when it comes to setup, implementation, analytical dashboards, and a few standout features and services.

Difference 1: Main offerings

Here is the difference in the main offerings. 

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Difference 2: Technical configuration

This is how each platform is set up and customized.

Sierra.ai 

Sierra.ai offers two main deployment options, i.e., Agent SDK and Agent Studio. They are not separate products that you buy individually; they’re two interfaces within a single platform offered by Sierra.ai.

1. Agent Software Development Kit (SDK) - For developers

• Code-based interface to define logic, actions, integrations, and connect to CI/CD workflows.
• Create composable functions (aka “skills”) that connect to CRMs, APIs, databases, etc.
• Implement version-controlled workflows and safely deploy updates.
• Define business logic and fallback behavior.

2. Agent Studio -  For the CX team

• No-code interface to customize brand tone, define intent flows, monitor performance, and tune conversations.
• Set escalation paths and AI guardrails.
• Label training data, test scenarios, and monitor live performance.
• Make updates without needing to involve developers.

Decagon.ai

Decagon.ai provides Agent Operating Procedures (AOPs) that allow teams to blend natural-language instructions (authoritative business logic or SOPs) with code‑based guardrails.

• These AOPs define how an AI agent handles specific tasks, e.g., “process refund” or “book ticket”, and can be iterated rapidly for new business cases.
• ‍Technology teams build the guardrails, system integrations (CRM, knowledge bases, payments), and validation logic
• Business/CX teams define and tune AOP logic in natural language, without coding. 
• Supported by robust testing infrastructure: simulation tools, versioning, agent behavior validation, and monitoring ensure predictable and high-quality performance

Crescendo.ai 

Crescendo.ai is a fully managed CX operations platform. Advanced AI agents are deployed by experts with experience across 100+ omnichannel AI implementations.  

Implementation services: Their implementation team takes care of everything related to AI agents. It includes

• AI agent onboarding
• app integrations 
• data migration, 
• CRM, ticketing, and knowledge base connections,
• workflow creation. 

No heavy lifting required on your end.

CX services: Their CX experts will first understand your business requirements and outcomes and then customize the omnichannel AI agents to match your brand voice, preferred languages, and intent flows. They’ll also train and provide an operations team to monitor performance, generate analytics, and continuously optimize the deployment.

In short, Crescendo handles all the tech and deployment tuning, giving you a hands-free implementation experience.

Difference 3: CSAT calculations

Customer satisfaction score (CSAT) is one of the crucial indicators of the quality of customer support. There is an acute difference in CSAT calculation capacity among these three platforms. 

Sierra.ai: Manual customer surveys + AI-derived metrics

• Combines manual customer surveys with AI-derived metrics and performance indicators for CSAT, giving teams a multi-dimensional view of satisfaction and agent effectiveness.
• Provides a key metrics dashboard that tracks critical support metrics (e.g. CSAT, resolution rate) for the AI agent. 

Decagon.ai: Manual customer surveys

• Relies on traditional post-interaction surveys where users are prompted to rate their experience on a scale. Typically focused on satisfaction or likelihood to recommend. 
• Integrates CSAT with its analytics and alerting workflows (like Watchtower), enabling teams to monitor satisfaction trends, flag anomalies, and correlate satisfaction by channel or language cohort. 

Crescendo.ai: 100% automated, optional manual surveys

• Calculates CSAT scores completely automatically, without relying on manual surveys.
• Analyzes every conversation in real time, detecting emotional tone, specific keywords/categories, the speed and quality of resolution, and how the interaction ends. 
• These factors are combined with performance indicators like escalation rates and resolution success to generate accurate CSAT scores for 100% of conversations.
• Complete and unbiased view of customer satisfaction, even from customers who never respond to traditional feedback requests.

Difference 4: Managed services

Sierra, Decagon, and Crescendo.ai differ significantly in the level of support and additional outsourcing services they offer beyond just AI agents.

Sierra.ai

• AI agent technology only, no managed services 

Decagon.ai 

• AI agent technology only, no managed services  

Crescendo.ai 

AI agents + Human-backed services.

It provides fully managed services which include,

• AI agent setup and continuous tuning (AI deployment engineer -AIDE, AI training, Knowledge management, technology implementation, AI optimization.
• The AIDE acts as the technical lead for the deployment, partnering closely with the partner to ensure a successful setup.They collaborate with project management, Launch Success, product, QA, Customer Success, Knowledge Management, and other teams throughout the deployment.
• 3,000+ customer support representatives, global team with multilingual capacity.
• Technology platform system integrations
• Brand-aligned staffing (Operations manager, team lead, associates, QA experts)

These services come bundled into Crescendo’s per-outcome pricing model, with no hidden fees or add-ons.

Difference 5: Cost

Pricing structure and key cost considerations.

Sierra.ai

• Outcome-based pricing: standard price tiers or per-unit rates not published. 

Decagon.ai 

It has two pricing models. 

• Per-conversation pricing: a flat rate per interaction, regardless of resolution outcome.
• Per-resolution pricing: a higher rate is paid only when the AI fully resolves the request without escalation.

Crescendo.ai 

• Outcome-based pricing: plans start at $2.99 per outcome (includes fully-managed service)

Difference in the pricing explained: Sierra.ai is likely more expensive, given its outcome-based structure and enterprise-focused positioning. Decagon.ai falls into mid-range and predictable pricing, especially with its per-conversation billing, allowing easier forecasting and control. Crescendo.ai tends to be the most budget-friendly option among all, where its per-resolution pricing floats around $2.99/resolution (subject to vary on the basis of ticket volume and technical complexity), which includes everything, from AI agents to onboarding and human-backed outsourcing services. 

Difference 6: Handoff techniques 

While all these platforms offer seamless handoffs, the technique they use is somewhat different. 

Sierra.ai: 

• Define escalation paths via Agent Studio
• Seamlessly transfers the customer to a human agent, complete with an AI-generated summary of the conversation and context.

Decagon.ai: 

• The hand-off logic is written as AOPs, so you can define conditions when to escalate (e.g., low confidence, specific intents, timeouts).
• Full context (conversation history, customer data, what it has done so far) passed to the human agent.
• Supports flexible handoff patterns, e.g. escalating in the middle of a chat or call, or even returning the conversation back to the AI after human fixes part of the problem.

Crescendo.ai: 

• Hand-off logic configurable via sentiment cues, pre-defined hand-off rules, or other custom-defined escalation criteria.
• If a customer expresses frustration, anger, or disappointment, whether through specific keywords or emotional tone, the AI agent can trigger a handoff, even if the situation doesn’t match a typical escalation condition.
• Hand-off is continuously monitored by the Crescendo operations team on a daily basis and routed based on expertise and availability of associates. This ensures customers are routed to the right person at the right time, without delays, dead ends, or repetition.

Difference 7: Language support 

While all these platforms, Decagon.ai, Sierra.ai, and Crescendo.ai, offer multilingual capabilities for AI agents, there are slight differences in their offerings.
Expanders

Sierra.ai 

• Supports 30+ languages across omnichannels 
• Language-agnostic reporting that automatically tags and analyzes multilingual interactions

• Supports dynamic agent translation, enabling responses in multiple languages drawn from a single knowledge source without pre-translated content.

Decagon.ai 

• Delivers global omnichannel language support, but does not publish a specific count.

• Does not offer native knowledge-base translation; multilingual responses rely on runtime interpretation of a base content repository.

Crescendo.ai

• Supports 50 languages across omnichannels
• Multilingual reporting and analytics 
• Supports dynamic agent translation via Automatic Speech Recognition (ASR), enabling responses in multiple languages drawn from multiple knowledge-base sources without pre-translated content.

Difference 8: Business-level details

• Sierra.ai: Founded in early 2023 by ex‑Salesforce co‑CEO Bret Taylor and former Google exec Clay Bavor. Raised $285 M to date, including a $175 M Series A at a $4.5 B valuation. Served Eventbrite, Duolingo, Chime, Curology, etc.; resolution rate is around 90%.
• Decagon.ai: Founded in 2023 by Jesse Zhang and Ashwin Sreenivas. Raised ~$100 M (seed + Series A), currently in the process of raising at a $1.5 B valuation by mid‑2025. Works with Sonos, WeightWatchers, SiriusXM, ADT, Casper; around 70% auto-resolution rate. 
• Crescendo.ai: Born in 2024 via General Catalyst, co‑founded by Anand Chandrasekaran, Andy Lee, Matt Price, and Slava Zhakov. Acquired PartnerHero, hit ~$91 M ARR, and raised a $50 M Series C at a $500 M valuation. Major clients include Lovepop, Rachio, Rio, and Webconnex.Crescendo.ai resolves 100% of support tickets—up to 90% handled by AI agents, and the rest seamlessly managed by their own human support reps.

Final words on Decagon.ai vs Sierra.ai vs Crescendo.ai

• Pick Sierra.ai if your business needs deep integrations, values tight engineering control, and has the time and budget for a customized rollout. It’s best suited for enterprises with dedicated engineering teams to build and maintain custom AI agents.
• Choose Decagon.ai if you need faster deployment than Sierra.ai, strong AI autonomy, and transparent control over logic.
• Choose Crescendo.ai if you want advanced AI support agents with hands-free deployment, fully managed end-to-end services, and brand-aligned human-backed services to handle escalations during off-hours, holidays, or seasonal spikes.