Best HappyRobot alternatives

R

Retell AI

Free

Voice & speech

#1 AI Voice Agent Platform for Automating Phone Calls

$0.07–$0.31/min for AI Voice Agents; $0.002+/msg for AI Chat Agents. $10 free credits at signup, no annual contract. Enterprise plan available with custom pricing.

H

Hume AI

Free

Voice & speech

The data and evaluation layer for emotionally intelligent voice AI

Free plan at $0/month; Starter at $3/month; Creator at $7/month (1st month 50% off); Pro at $70/month; Scale at $200/month; Business at $500/month; Enterprise custom pricing. Usage-based overages apply for TTS characters and EVI minutes.

V

Vapi

Free

Voice & speech

Voice agents for builders

No-cost entry tier with $5 free credits and $0.05/min Vapi hosting (usage-based, models at cost). Core plan at $29/month. Pro at $999/month minimum (10% of Vapi hosting fee). Premier is custom/contact sales. Add-ons include HIPAA compliance ($2,000/month), additional concurrency ($10/line/month), and additional organizations ($20/org/month).

A

AssemblyAI

Free

Voice & speech

Voice AI infrastructure for builders — industry-leading speech-to-text and voice agent APIs

Free tier available · Enterprise pricing on request

S

Symbl.ai

Free

Voice & speech

LLM-powered real-time conversation intelligence for voice, video, and chat at enterprise scale

F

Fireflies.ai

Free

Voice & speech

AI meeting notes with search, sentiment analysis, and CRM integration for sales teams.

Free plan forever ($0); Pro at $10/seat/month (billed annually); Business at $19/seat/month (billed annually); Enterprise at $39/seat/month (annual only).

R

Rev AI

Free

Voice & speech

The world's most accurate speech-to-text API for developers, built for speed and global scale.

Pay-as-you-go with free credits (5 hours of Reverb ASR). Reverb Transcription: $0.20/hr (English); Reverb Foreign Language: $0.30/hr (57+ languages); Whisper Large: $0.005/min; Human Transcription: $1.99/min; Forced Alignment: $0.003/min; Language ID: $0.003/min; Translation: $0.002–$0.025/min; Sentiment Analysis: $0.0008/10 words; Summarization: $0.002–$0.025/min; Topic Extraction: $0.0008/10 words. Enterprise: volume-based pricing.

K

Kore.ai

Automation & agents

The AI-programmable agent platform for building, scaling, and optimizing enterprise AI agents

C

Cartesia

Free

Voice & speech

Architecting AI that learns and interacts like humans — ultra-low latency voice AI

Free plan at $0/mo (20K credits, $1 prepaid agents); Pro at $5/mo (100K credits, $5 prepaid agents); Startup at $49/mo (1.25M credits, $49 prepaid agents); Scale at $299/mo (8M credits, $299 prepaid agents); Enterprise custom. Voice agent calls at $0.06/min plus $0.014/min telephony for Cartesia-provided numbers.

H

HoneyHive

Free

AI observability

Agent Observability and Evaluation Platform

Free tier includes 10,000 events/month, up to 5 users, 30-day data retention, automated & human evaluations, prompt versioning, CI/CD integration, and community support. Enterprise tier offers custom usage limits, unlimited users & workspaces, SAML & custom SSO, custom data retention, uptime SLA, custom DPA and BAA, dedicated TAM & QBRs, and optional self-hosting/hybrid/single-tenant deployment.