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Now in private beta — 18+ providers integrated

One API.
Every voice provider.

240+ provider combinations. Zero way to know which stack is best. VoiceForge benchmarks every combo and routes to the winner automatically.

$100 free credits · No credit card
voiceforge optimize --language thai --usecase sales
STTDeepgram
LLMGPT-4.1
TTSCartesia
RankStackLatency
#1Deepgram + GPT-4.1 + Cartesia195ms
#2Cartesia STT + GPT-4.1 + Cartesia245ms
#3Deepgram + Claude + ElevenLabs312ms

Recommended: Deepgram + GPT-4.1 + Cartesia

Latency: 195ms (P95: 280ms) | Naturalness: 4.2/5 UTMOS | Cost: $0.003/call

Universal voice infrastructure.

Connect once. We handle 18+ provider integrations, benchmark every combination, and route to the best one.

Universal Infrastructure

Connect your app once. VoiceForge acts as a unified abstraction over every major STT, LLM, and TTS provider.

Your App / Agent
VoiceForge API
Smart Routing Engine
STT
Multiple
LLM
Multiple
TTS
Multiple

Smart Routing

Tell us your use case, language, and priority. We benchmark every combination and return the best stack.

Optimize for Latency
Optimize for Cost
Optimize for Quality

Automatic Failover

If Deepgram goes down, VoiceForge instantly routes to the next-best ranked combination. Zero downtime.

Deepgram: 503 Timeout
Re-routing...
Cartesia STT: Connected

Quality Testing & Benchmarking

Automated latency benchmarks (P50, P95, P99) alongside UTMOS scoring and native speaker marketplace testing for true naturalness verification.

Latency (P95)Fast
Naturalness4.2/5
Cost$0.003

Provider-agnostic by design. ElevenLabs will never recommend Cartesia for Thai. We will.

How It Works

Three steps to the perfect stack.

01

Define

Set your language, use case, latency targets, and budget. Takes 30 seconds.

02

Benchmark

VoiceForge runs 50+ STT+LLM+TTS combinations against your criteria automatically.

03

Deploy

Get ranked results with data. Apply the winning config with one click.

Providers can't build this.

Neutrality is the moat. Vapi benchmarks within their stack. ElevenLabs recommends ElevenLabs. We recommend whoever's best.

Capability
Platforms & Providers
VoiceForge
Unified API (all providers)
Locked to their stack
Yes
Cross-provider benchmarking
Only benchmark themselves
Yes
Human naturalness testing
Automated metrics only
Yes
Automatic failover
No cross-provider failover
Yes

Every major provider.

18+ voice AI providers across the full pipeline. New providers added monthly.

240+ possible combinations

Speech-to-Text
DeepgramCartesiaWhisperAssemblyAIAzure SpeechGoogle STT+ more
Language Models
GPT-4.1Claude 4Gemini ProLlama 3MistralCommand R++ more
Text-to-Speech
CartesiaElevenLabsPlayHTAzure TTSGoogle TTSRime+ more

Frequently asked questions

We run your actual prompts through every STT + LLM + TTS combination you select. Each combo is measured on latency (P50, P95, P99), audio quality (UTMOS score), language accuracy, and cost per call. Results are ranked by the priority weights you set, so you get the best stack for your specific use case.