Ultravox (formerly Fixie.ai) vs 11x
Detailed side-by-side comparison to help you choose the right tool
Ultravox (formerly Fixie.ai)
🔴DeveloperVoice AI Tools
Real-time, speech-native voice AI platform that processes audio directly without text conversion, enabling fast, natural voice conversations for AI agents with sub-second latency and preservation of paralinguistic signals.
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Starting Price
Free11x
🟢No CodeVoice AI Tools
11x provides AI digital workers for sales development, featuring Alice the AI SDR for autonomous outbound email prospecting and Julian the AI Phone Agent for intelligent voice conversations. The platform handles end-to-end sales development workflows including prospect identification, research, personalized outreach, follow-ups, and meeting scheduling — operating 24/7 to generate qualified pipeline at a fraction of the cost of human SDR teams.
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Starting Price
~$5,000/monthFeature Comparison
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Ultravox (formerly Fixie.ai) - Pros & Cons
Pros
- ✓Speech-native model processes audio directly, eliminating STT→LLM→TTS pipeline latency and producing sub-second response times that feel conversational rather than transactional.
- ✓Preserves paralinguistic information (tone, pace, hesitation) that traditional cascaded pipelines discard, leading to more natural turn-taking and barge-in handling.
- ✓Open-source Ultravox model published on Hugging Face gives teams the option to self-host for cost, latency, or compliance reasons instead of being locked into a proprietary API.
- ✓First-class integration path with telephony providers like Twilio plus WebRTC support, making it practical to ship real phone-call agents and in-app voice without building media plumbing from scratch.
- ✓Tool/function calling is supported inside live voice sessions, so agents can take real actions (lookups, transfers, bookings, CRM writes) rather than only chatting.
- ✓Developer-first surface area: API, JavaScript SDK, and clear primitives for building agents, which suits engineering teams already comfortable with LLM tooling.
Cons
- ✗Pure developer platform with no visual builder or no-code flow designer, so non-engineers cannot stand up an agent without writing code.
- ✗Voice and language coverage is narrower than long-established TTS/STT vendors that have spent years accumulating locales, accents, and voice libraries.
- ✗Speech-native architecture is newer than the cascaded STT+LLM+TTS approach, so tuning, debugging, and observability tooling around it is less mature than the pipeline ecosystem.
- ✗Costs at scale can be hard to predict for high-volume telephony workloads because pricing combines model usage with telephony minutes from third-party providers.
- ✗Branding/identity churn (Fixie.ai → Ultravox) means older documentation, blog posts, and integration guides on the public web can be inconsistent or outdated.
11x - Pros & Cons
Pros
- ✓Deploys true end-to-end autonomous SDR workflow (prospecting, enrichment, personalization, sequencing, and meeting booking) without requiring human operators to manage campaigns or write templates, freeing sales teams to focus on closing deals rather than top-of-funnel activities.
- ✓Two coordinated digital workers (Alice for written outbound, Julian for voice) cover both email/LinkedIn and phone channels under one platform, eliminating the need to stitch together separate tools for multi-channel prospecting and reducing vendor sprawl.
- ✓Marketed cost savings of roughly 50% versus a human SDR team make the ROI case clear for enterprise buyers — Alice costs approximately $50,000–$60,000 annually compared to $100,000+ for a fully loaded human SDR including salary, benefits, tools, and management overhead.
- ✓Built-in access to a large prospect database of over 200 million contacts eliminates the need for separate data providers like ZoomInfo or Lusha, reducing total stack cost and simplifying the workflow from prospect identification to outreach execution.
- ✓Enterprise-grade positioning with offices in San Francisco and London, CRM integrations with Salesforce and HubSpot, SOC 2 Type II compliance, and GDPR-compliant data processing gives procurement and security teams confidence during vendor evaluation and approval.
- ✓24/7 execution with continuous learning loops means campaigns optimize without manual A/B testing — Alice analyzes engagement data across all outreach to improve subject lines, messaging, and send timing automatically, compounding performance gains over time.
Cons
- ✗Enterprise-only annual pricing with no public self-serve tier shuts out SMBs, startups, and individual sales professionals who cannot commit $50,000+ annually or navigate a multi-week enterprise sales process just to evaluate the product.
- ✗AI-generated outbound at scale carries real deliverability and brand-reputation risk if email warm-up, domain rotation, and content quality are not carefully managed — some users report initial spam folder placement and inconsistent email quality across prospect segments.
- ✗Heavy reliance on automated outreach can trigger LinkedIn rate limits, account restrictions, or platform bans if volume thresholds are exceeded, particularly for users whose LinkedIn accounts lack established activity histories or connection networks.
- ✗The 'replace your SDR team' positioning has drawn public criticism from some early customers on Reddit and review sites who experienced underwhelming results, with complaints including poorly targeted prospects, generic-sounding personalization, and difficulty canceling annual contracts.
- ✗Limited transparency on pricing, contract minimums, and ramp expectations without going through a full sales process makes comparison shopping difficult and has eroded trust among prospects who feel pressured into commitments before fully understanding total cost of ownership.
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