One API.
Every voice provider.
240+ provider combinations. Zero way to know which stack is best. Speko benchmarks every combo and routes to the winner automatically.
Recommended: Deepgram + GPT-4.1 + Cartesia
195ms P50 · 4.2/5 UTMOS · $0.003/call
Universal voice infrastructure.
Connect once. We handle 18+ provider integrations, benchmark every combination, and route to the best one.
Universal Infrastructure
One API for every major STT, LLM, and TTS provider. Connect once, access 18+ providers instantly.
Smart Routing
Define your use case, language, and priority. We benchmark every combination and route to the best stack.
Quality Testing
Automated latency benchmarks, UTMOS scoring, and native speaker testing for true naturalness verification.
Provider-agnostic by design. ElevenLabs will never recommend Cartesia for Thai. We will.
How It Works
Three steps to the perfect stack.
Define
Set your language, use case, latency targets, and budget. Takes 30 seconds.
Benchmark
Speko runs 50+ STT+LLM+TTS combinations against your criteria automatically.
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.
Unified API across all providers
Others lock you to their stack
Cross-provider benchmarking
Others only benchmark themselves
Human naturalness testing
Others rely on automated metrics alone
Automatic cross-provider failover
Others have no failover across providers
Every major provider.
18+ voice AI providers across the full pipeline. New providers added monthly.
240+ possible combinations
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.