Retell AI vs iSpeech TTS & Speech API

Comparing the features of Retell AI to iSpeech TTS & Speech API

Feature
Retell AI
iSpeech TTS & Speech API

Capability Features

Agent Builder
Agent Testing
API Access
API Requests per Month
100000000
Appointment Scheduling
Auto-Sync Knowledge Base
Automatic Scalability
Millions of concurrent calls
Batch Calls
Branded Caller ID
Call History
Call Monitoring
Call Transfer Options
Cloud and Embedded TTS
Create IVR Prompts
Custom Voice Cloning
Developer Signups
80000
Edge Case Handling
Global Reach
Industry Compliance
SOC 2 Type 1&2HIPAAGDPR
LLM-Powered
Low Latency
500ms latency
Multi-language Support
18+ languages
Multiple Deployment Channels
AI phone callsWeb callsSMSChat
Natural Language Conversations
Navigate Through IVR
No Concurrency Limits
Open Source SDKs
Platform Uptime
99.99% uptime
SDK Availability
Speech Rate Adjustment
SlowRegularFast
Speech Recognition
Supported Language List
US EnglishUK EnglishAustralian EnglishUS SpanishChineseHong Kong ChineseTaiwan ChineseJapaneseKoreanCanadian EnglishHungarianBrazilian PortugueseEuropean PortugueseEuropean SpanishEuropean CzechEuropean DanishEuropean FinnishEuropean FrenchEuropean NorwegianEuropean DutchEuropean PolishEuropean ItalianEuropean TurkishEuropean GreekEuropean GermanRussianSwedishCanadian FrenchArabic
Talking Stickers
Text to Speech
Verified Phone Numbers
Voicemail Detection

Integration Features

Audiobook Support
Chrome Extension
Connected Vehicle Integration
CRM/Automation Integrations
Cal.comn8nGoHighLevelTwilioVonageOpenAI
Integrates with Any CRM
Integrates with Any Telephony
Integrates with Automation Platforms
Integrates with Databases
Mobile Integration
SAPI Integration
Telephony Integration
TwilioVonageTelnyxPlivoRingCentral

Limitation Features

No Desktop App Mentioned
No Mentioned Self-hosting
No Public Pricing Listed
Registration Required for Downloads
TTS for Non-Commercial Use Only

Pricing Features

Free Tier
IVR Prompts Free Sample
Pricing Plan Details