If you're trying to choose between Vapi, Synthflow, Bland AI, and Retell AI for your voice AI needs, you've come to the right place. We used Oden to analyze over 1500+ G2 reviews, dug through Reddit discussions, and compared current pricing across all four platforms to give you a clear picture of which one might work best for you.

This comparison covers everything from pricing and features to what real customers are saying. Whether you're a developer looking for flexibility, a business owner wanting something easy to use, or an enterprise needing enterprise-grade solutions, we break down the strengths, weaknesses, and true costs of each platform so you can make an informed decision.

Which voice AI platform has the best G2 rating?

G2 Performance Metrics

Source: Retell AI G2 Reviews, Vapi G2 Reviews, Synthflow G2 Reviews

How much do voice AI platforms really cost?

Vapi Pricing

Source: Vapi Pricing

Pay-As-You-Go: $0.05/min (platform fee only)

• 10 concurrent calls included
• $10 free credits to start
• Critical Note: Does NOT include STT, LLM, or TTS costs
• True Cost: $0.13-$0.31+/min when all services included

Enterprise: Custom annual contract

• Volume-based pricing
• Includes model provider costs
• SOC2, HIPAA available
• 99.99% uptime SLA
• Private Slack support

Hidden Costs:

• HIPAA compliance: $1,000/month add-on
• Additional concurrency: $10/line/month
• Must contract separately with: Twilio/Telnyx (telephony), Deepgram/AssemblyAI (STT), OpenAI/Anthropic (LLM), ElevenLabs/PlayHT (TTS)

Reddit Feedback: "Vapi is by far the best solution for simplicity but yea $0.05/minute is hefty (+ AI cost)" - Vapi AI Agent Cost and Alternatives Discussion

Synthflow Pricing

Source: Synthflow Pricing

Starter: $29/month

• 50 minutes included
• 5 concurrent calls
• All AI services bundled

Pro: $450/month ($375/month annual)

• 2,000 minutes, then $0.13/min overage
• 25 concurrent calls
• 8,000 custom workflows

Growth: $900/month ($750/month annual)

• 4,000 minutes, then $0.12/min overage
• 50 concurrent calls
• 25 subaccounts

Agency: $1,400/month ($1,250/month annual)

• 6,000 minutes, then $0.12/min overage
• 80 concurrent calls
• Unlimited subaccounts
• White-label platform

Enterprise: Custom pricing

• As low as $0.08/min for high volume
• SIP trunk integration
• SOC2, HIPAA, GDPR included

G2 Feedback: "Expensive (107 mentions), Cost Limitations (77 mentions)" as top cons. Multiple users requested "pay-as-you-go option" - Synthflow G2 Customer Reviews and Pricing

Reddit Complaint: "Synthflow rates aren't accurate, they hit me with a bait and switch after I paid for the '29/month' services half the tools I needed weren't even usable. Upgraded to a higher tier same story." - Synthflow AI Review: Small Business Call Automation

Bland AI Pricing

Source: Competitor research data

Start (Free): 100 calls/day

Build: $299/month

• 2,000 calls/day

Scale: $499/month

• 5,000 calls/day

Per-Minute Pricing: $0.09/min for active call time

Bland SMS: $0.02/message

Enterprise: Custom pricing

• Volume discounts available

Positioning: "Own your AI, don't rent it" - offers custom trained models, dedicated infrastructure, and protected data on customer's own servers - Bland AI

Retell AI Pricing

Source: Retell AI Pricing

Pay-As-You-Go: $0.07+/min for AI Voice Agents

• $0.002+/msg for AI Chat Agents
• $10 free credits
• 20 free concurrent calls
• 10 free knowledge bases

Component Breakdown:

• Conversation Voice Engine: $0.07-$0.08/min
• LLM costs: $0.003-$0.06/min (varies by model)
• Telephony: $0.015/min (Retell Twilio)

Enterprise: Starting at $8,000/month

• Discounted pricing based on volumes
• As low as $0.05/min
• Fully managed agent setup
• Premium Slack support

G2 Feedback: "Ease of Use (192 mentions), User Interface (66 mentions)" as top pros. "Pricing is a bit much. As a recent startup its forced me to be more conscious about spending" - Retell AI G2 Reviews and Product Overview

3. Positioning analysis

Vapi: Developer-First Infrastructure Platform

Core Positioning: "Voice AI agents for developers" - API-native platform for engineering teams

Key Differentiators:

• Maximum Flexibility: Bring-your-own models (STT, LLM, TTS)
• Developer Control: 4.2K+ configuration points, comprehensive API
• Production Scale: 150M+ calls processed, 99.99% uptime
• Sub-500ms latency: Custom real-time audio infrastructure
• Enterprise Security: SOC2, HIPAA, PCI compliant

Target Audience: Engineering-heavy teams at startups to Fortune 500 companies who need deep customization

Reddit Sentiment: "Vapi currently leads the market in voice agent performance" and "Vapi still wins for dev speed" - Vapi AI Agent Cost and Alternatives Discussion, Voice AI Bot Platform Comparison

Weaknesses:

• Complex pricing with multiple vendor bills
• Requires significant technical expertise
• Not suitable for non-technical teams
• "Too dev-heavy" per Reddit feedback

Synthflow: No-Code Enterprise Voice AI

Core Positioning: "No-code platform for deploying voice AI agents at scale" for BPO and contact centers

Key Differentiators:

• All-in-One Bundle: Voice API, LLM, transcriber included in pricing
• No-Code Builder: Visual workflow builder with 200+ integrations
• White-Label: Agency and reseller-friendly with unlimited subaccounts
• Sub-500ms latency: <500ms response time
• 30+ Languages: Multi-language support out of box

Target Audience: Agencies, BPOs, and businesses wanting turnkey solutions without engineering resources

G2 Strengths: "Ease of Use (265 mentions), Setup Ease (116 mentions)" - Synthflow G2 Reviews, Ratings, and Features Overview

G2 Weaknesses:

• "Expensive (107 mentions), Cost Limitations (77 mentions)"
• "Pricing could always be more affordable a pay as you go option would be nice"
• "Set up complexity as this needs to be more user-friendly"

Reddit Criticism: Multiple users report "bait and switch" pricing tactics, with starter plan features being "crippled unless you're paying enterprise" - Synthflow AI Review

Bland AI: Enterprise Conversational AI with Proprietary Models

Core Positioning: "The fastest conversational AI in the world" - enterprise-focused with custom AI models

Key Differentiators:

• Proprietary Models: Custom trained models (no OpenAI/Anthropic dependency)
• Conversational Pathways: Proprietary programming language for strict guardrails
• Massive Scale: Up to 1 million concurrent calls
• Omni-Channel: Voice, SMS, and Chat in one platform
• Forward-Deployed Engineers: Custom agent development with dedicated team

Target Audience: Large enterprises (Cleveland Cavaliers, Sears, Snapchat, Samsara) requiring custom models and dedicated infrastructure

Company Metrics:

• Founded: 2023
• Funding: $65M ($40M Series B, January 2025)
• Revenue: $3.8M (2024)
• Employees: 52

Unique Value: "Own your AI, don't rent it" - offers dedicated servers, custom voice actors, and protected data for IP-sensitive enterprises

Pricing Model: $0.09/min is competitive but requires understanding of call-day limits vs. minute-based pricing

Retell AI: Production-Ready Developer Platform

Core Positioning: "Developer-first platform for building, testing, deploying, and monitoring production-ready AI voice agents"

Key Differentiators:

• Highest G2 Rating: 4.8/5 with 780 reviews (best in category)
• Transparent Pricing: Clear component breakdown, true pay-as-you-go
• Conversation Flow Agent: Low margin of error, follows flows precisely
• ~500ms latency: Industry-leading response time
• 18+ Languages: Extensive language support
• Production Focus: Built for scale with 99.99% uptime

Target Audience: Developers and technical teams building production voice agents, from startups to enterprises

G2 Strengths:

• "Ease of Use (192 mentions)" - highest among all platforms
• "User Interface (66 mentions)"
• "The only platform with which you can develop production grade voice agents"
• "Very user friendly and intuitive...They offer a nice free version"

G2 Weaknesses:

• "Missing Features (45 mentions), Limited Features (32 mentions)"
• "Getting support has gotten a little more difficult now that it's more popular"
• Some users report "latency issues" and "bad dashboard"

Reddit Sentiment: "RetellAI feels steadier for production scale" and "Retell tends to be more developer-friendly and scalable" - Voice AI Bot Platform Comparison, Alternatives to Vapi for AI Phone Agents

How do Vapi, Synthflow, Bland AI, and Retell AI compare?

Vapi's $0.05/min does not include STT, LLM, TTS, or telephony costs

What do customers say about each platform?

Reddit Discussion Themes

Vapi Feedback:

• ✅ "Best solution for simplicity" and "leads the market in voice agent performance"
• ✅ "Developer-friendly API-first approach"
• ❌ "Very costly" - true cost $0.13-$0.31/min with all services
• ❌ "Too dev-heavy" for non-technical teams
• ❌ "Confusing pricing layers"

Synthflow Feedback:

• ✅ "Easy to use" and "user-friendly interface"
• ✅ "Good for quick prototypes"
• ✅ "Lowest latency" (though "almost identical to Vapi's speed")
• ❌ "Bait and switch" pricing complaints
• ❌ "Platform is crippled unless you're paying enterprise"
• ❌ "Expensive" - multiple users want pay-as-you-go

Bland AI Feedback:

• ✅ "Better for more detailed issues"
• ✅ "Handles appointment scheduling really well"
• Limited Reddit discussion compared to others
• Positioned as premium enterprise solution

Retell AI Feedback:

• ✅ "Steadier for production scale"
• ✅ "More developer-friendly and scalable"
• ✅ "Enterprise ready with compliance"
• ✅ "Good voice quality, solid analytics"
• ❌ "Hard pass" from one user citing billing/support issues
• ❌ Some report "latency" and "bad dashboard"

Source: Reddit discussions across multiple documents

G2 Review Patterns

Retell AI (4.8/5, 780 reviews):

• Top Pros: Ease of Use (192), User Interface (66)
• Top Cons: Missing Features (45), Limited Features (32)
• Quote: "The platform is incredibly intuitive to use, even for someone without a technical background like me"
• Quote: "Retell AI's voice agents sound natural — not robotic — and adapt tone, pacing, and emotion"

Synthflow (4.5/5, 899 reviews):

• Top Pros: Ease of Use (265), Setup Ease (116)
• Top Cons: Expensive (107), Cost Limitations (77)
• Quote: "Easy to use and user docs are constantly updated"
• Quote: "Pricing could always be more affordable a pay as you go option would be nice"

What are the strengths and weaknesses of each platform?

Vapi

Strengths:

• Maximum Developer Control: 4.2K+ configuration points, bring-your-own everything
• Market Leader in Flexibility: Best for custom integrations and deep customization
• Strong Community: 350K+ developers, 250K+ in community
• Production Scale: 150M+ calls, 99.99% uptime SLA
• Enterprise Security: SOC2, HIPAA, PCI compliant

Weaknesses:

• Complex Pricing: Requires 4-6 vendor contracts, true cost 3-6x advertised rate
• Technical Barrier: Not suitable for non-technical teams
• Hidden Costs: HIPAA $1k/mo, support requires Enterprise plan
• No G2 Presence: Lack of public review validation
• Multiple Bills: Separate invoices from each provider

Proof Point: "Vapi is by far the best solution for simplicity but yea $0.05/minute is hefty (+ AI cost). Other platforms will charge you $0.09 but you don't have any control over models" - Reddit discussion

Synthflow

Strengths:

• True No-Code: Visual builder with 200+ integrations
• All-Inclusive Pricing: Voice, LLM, transcriber bundled
• White-Label Ready: Unlimited subaccounts on Agency plan
• Strong G2 Presence: 899 reviews, 4.5/5 rating
• Fast Setup: "Easy to use" mentioned 265 times in G2 reviews

Weaknesses:

• Pricing Complaints: "Expensive" (107 mentions), "bait and switch" accusations
• Limited Flexibility: Cannot bring own models, locked into their stack
• Starter Plan Limitations: $29 plan reportedly has unusable features
• Setup Complexity: Despite "no-code" claims, users report complexity
• Support Issues: "Support needs to be faster"

Proof Point: "Synthflow rates aren't accurate, they hit me with a bait and switch... half the tools I needed weren't even usable. Upgraded to a higher tier same story. Feels like the whole platform is crippled unless you're paying enterprise" - Reddit review

Bland AI

Strengths:

• Proprietary Technology: Own models, no dependency on OpenAI/Anthropic
• Conversational Pathways: Unique programming language for strict control
• Massive Scale: Up to 1M concurrent calls
• Enterprise Focus: Forward-deployed engineers, custom development
• Strong Funding: $65M raised, backed by major VCs

Weaknesses:

• No G2 Reviews: Zero public review presence
• Enterprise-Only: Not accessible for SMBs or startups
• Complex Setup: Requires forward-deployed engineers
• Limited Transparency: Pricing and features less publicly documented
• Young Company: Founded 2023, less proven track record

Proof Point: "Bland AI is a conversational AI platform that automates phone calls for enterprises using hyper-realistic AI agents... $65M ($40M Series B, January 2025)" - Competitor research data

Retell AI

Strengths:

• Highest G2 Rating: 4.8/5 with 780 reviews - best in category
• Transparent Pricing: Clear component breakdown, true pay-as-you-go
• Production-Ready: "The only platform with which you can develop production grade voice agents"
• Ease of Use: "Incredibly intuitive" even for non-technical users
• Natural Voice Quality: "Sound natural — not robotic"

Weaknesses:

• Limited Features: "Missing Features" (45 mentions), "Limited Features" (32 mentions)
• Support Scaling Issues: "Getting support has gotten a little more difficult now that it's more popular"
• Dashboard Complaints: Some users report "bad dashboard"
• Occasional Latency: Reports of "voice calling lags sometimes"
• Billing Issues: One user reported "hard pass" due to billing problems

Proof Point: "The platform is incredibly intuitive to use, even for someone without a technical background like me. I was able to set up and deploy AI voice agents without needing to write code" - G2 Review

7. Market positioning map

Key takeaways for sales assets

Pricing Messaging:

• Vapi: "True cost is 3-6x advertised rate when you add required services"
• Synthflow: "Users report 'bait and switch' - starter features don't work"
• Bland AI: "Enterprise-only pricing, not accessible for most businesses"
• Retell AI: "Most transparent competitor, but limited features"

Positioning Messaging:

• Vapi: "For developers who want maximum control but can manage complexity"
• Synthflow: "For agencies wanting white-label, but expect pricing surprises"
• Bland AI: "For Fortune 500 enterprises with custom model requirements"
• Retell AI: "For developers wanting ease of use, but may hit feature limits"

Competitive Proof Points:

• G2 Ratings: Retell (4.8/5, 780 reviews) > Synthflow (4.5/5, 899 reviews) > Vapi/Bland (no presence)
• Reddit Sentiment: Vapi praised for flexibility but "costly"; Synthflow criticized for "bait and switch"; Retell "steadier for production"
• True Pricing: Vapi $0.13-$0.31/min | Synthflow $0.12-$0.13/min | Bland $0.09/min | Retell $0.07+/min

9. Sources & links

Competitor Research Data:

• Bland AI Tracked Competitor Data
• Retell AI Tracked Competitor Data
• Synthflow AI Tracked Competitor Data

G2 Reviews:

• Retell AI G2 Reviews (780 reviews, 4.8/5)
• Synthflow G2 Reviews (899 reviews, 4.5/5)

Reddit Discussions:

• Vapi AI Agent Cost and Alternatives
• Synthflow AI Review: Small Business Call Automation
• Voice AI Bot Platform Comparison
• Alternatives to Vapi for AI Phone Agents

Current Pricing Pages:

• Vapi Pricing
• Synthflow Pricing
• Retell AI Pricing
• Bland AI