# Modulate

> Build with the modulate.ai models — real-time speech-to-text, synthetic voice detection, and PII/PHI redaction at scale.

## Docs

- [Language Detection Batch](https://docs.modulate.ai/api-reference/language-detection/batch.md): Identify the spoken language of an audio file. Returns an ISO 639-1 language code, human-readable display name, and confidence score in a single synchronous response.
- [Language Detection](https://docs.modulate.ai/api-reference/language-detection/overview.md): Velma-2 language detection API — identify the spoken language of an audio file in a single synchronous HTTP POST.
- [Music Detection Batch](https://docs.modulate.ai/api-reference/music-detection/batch.md): Classify music and speech in an audio file. Returns frame-level probabilities, a primary label, and percentage breakdowns of content type.
- [Music Detection](https://docs.modulate.ai/api-reference/music-detection/overview.md): Velma-2 music detection APIs — batch classification and real-time streaming over WebSocket.
- [Music Detection Streaming](https://docs.modulate.ai/api-reference/music-detection/streaming.md): Real-time frame-level music and speech classification over WebSocket. Frames are emitted progressively as audio is streamed.
- [PII/PHI Redaction Batch](https://docs.modulate.ai/api-reference/redaction/batch.md): Transcribe a pre-recorded audio file and redact PII/PHI from both the transcript text and the returned audio.
- [PII/PHI Redaction](https://docs.modulate.ai/api-reference/redaction/overview.md): Velma-2 PII/PHI redaction — transcribe audio, replace sensitive spans with entity-type tags, and silence the matching audio ranges.
- [PII/PHI Redaction Streaming](https://docs.modulate.ai/api-reference/redaction/streaming.md): Real-time PII/PHI redaction over WebSocket — receive a redacted transcript and a redacted MP3 clip per utterance.
- [Speech-to-Text Transcription Batch Multilingual](https://docs.modulate.ai/api-reference/stt/batch.md): Multilingual batch transcription with automatic language detection, speaker diarization, emotion and accent detection, and PII/PHI tagging.
- [Speech-to-Text Transcription Batch English VFast](https://docs.modulate.ai/api-reference/stt/batch-english-vfast.md): Fast English-only batch transcription. Trades enrichment features for the lowest possible turnaround.
- [Speech-to-text Transcription](https://docs.modulate.ai/api-reference/stt/overview.md): Velma-2 speech-to-text APIs — multilingual batch transcription, fast English-only batch, real-time streaming, and low-latency English streaming.
- [Speech-to-Text Transcription Streaming Multilingual](https://docs.modulate.ai/api-reference/stt/streaming.md): Real-time speech-to-text over WebSocket, with optional speaker diarization, emotion detection, accent detection, and PII/PHI tagging.
- [Speech-to-Text Streaming English](https://docs.modulate.ai/api-reference/stt/streaming-vfast.md): Low-latency English speech-to-text over WebSocket. Emits rolling partial transcripts during streaming and a single final transcript at end-of-stream. No enrichments.
- [Deepfake Detection Batch](https://docs.modulate.ai/api-reference/svd/batch.md): Detect synthetic (AI-generated) voice in a pre-recorded audio file. Returns per-frame deepfake scores.
- [Deepfake Detection](https://docs.modulate.ai/api-reference/svd/overview.md): Velma-2 synthetic voice detection — deepfake detection on pre-recorded files (batch) or live audio (streaming).
- [Deepfake Detection Streaming](https://docs.modulate.ai/api-reference/svd/streaming.md): Real-time deepfake detection over WebSocket, with per-frame verdicts and confidence scores delivered as analysis windows complete.
- [Velma Batch](https://docs.modulate.ai/api-reference/velma/batch.md): Run full conversation analysis on an uploaded audio file — transcription, conversation type, participant roles, behaviors, topics, sentiment, and summary in one response.
- [Velma](https://docs.modulate.ai/api-reference/velma/overview.md): Velma-2 is an audio-native voice intelligence model over REST or WebSocket — surface behaviors and risks in voice conversations using pre-built or custom detectors.
- [List behavior presets](https://docs.modulate.ai/api-reference/velma/presets.md): List the catalog of behavior presets that can be referenced from a BatchConfig using the preset:<identifier> syntax.
- [Velma Streaming](https://docs.modulate.ai/api-reference/velma/streaming.md): Real-time conversation analysis over WebSocket — stream audio and receive clips, conversation type, participant roles, behaviors, topics, sentiment, and a summary as they are produced.
- [FAQ](https://docs.modulate.ai/faq.md): Frequently asked questions about authentication, models, audio formats, pricing, rate limits, streaming, errors, privacy, and support.
- [Deepfake detection](https://docs.modulate.ai/get-started/deepfake.md): Detect synthetic (AI-generated) voice in recorded files or live audio streams — per-frame verdicts with confidence scores.
- [Language detection](https://docs.modulate.ai/get-started/language-detection.md): Identify the spoken language of an audio file — confidence-scored results across 100 languages in a single synchronous API call.
- [Music detection](https://docs.modulate.ai/get-started/music-detection.md): Classify audio as music, speech, or neither — frame-level probabilities, batch and real-time streaming.
- [PII/PHI redaction](https://docs.modulate.ai/get-started/pii.md): Remove sensitive content from transcripts and silence the matching audio ranges — batch and real-time streaming.
- [Speech to text](https://docs.modulate.ai/get-started/stt.md): Transcribe audio with speaker diarization, emotion, accent, and PII/PHI tagging — batch or real-time streaming.
- [Audio formats and preprocessing](https://docs.modulate.ai/guides/audio-formats.md): Supported audio formats across all Velma-2 endpoints, with guidance on format selection, conversion, and the special requirements of the streaming SVD endpoint.
- [Authentication and rate limits](https://docs.modulate.ai/guides/authentication.md): How to authenticate Modulate API requests, what rate limits apply, and how to handle auth and rate limit errors.
- [Code examples by language](https://docs.modulate.ai/guides/code-examples.md): Working integration patterns in cURL, Python (sync, async, concurrent), and JavaScript / Node.js with WebSocket support.
- [Music detection quickstart](https://docs.modulate.ai/guides/music-detection-quickstart.md): Stream audio to the music detection API over WebSocket and receive frame-level music and speech probabilities in real time.
- [STT enrichment features](https://docs.modulate.ai/guides/stt-enrichment-features.md): Optional metadata you can request alongside transcription — speaker diarization, emotion, accent, PII/PHI tagging, and synthetic voice scoring.
- [How synthetic voice detection works](https://docs.modulate.ai/guides/synthetic-voice-detection.md): The mechanics behind Velma-2's synthetic voice detection — windowing, silence trimming, confidence scoring, and the no-content verdict.
- [Troubleshooting](https://docs.modulate.ai/guides/troubleshooting.md): Common errors organized by category, with causes and fixes — auth, rate limits, audio validation, timeouts, and server errors.
- [Which API should I use?](https://docs.modulate.ai/guides/which-api.md): Pick the right Velma-2 endpoint based on your latency needs, language requirements, audio format constraints, and required features.
- [Modulate developer docs](https://docs.modulate.ai/index.md): Build with Modulate's voice AI platform. Start with Velma for complete conversation intelligence, or use individual models for transcription, deepfake detection, music detection, emotion detection, PII redaction and more.
- [Quick start](https://docs.modulate.ai/quickstart.md): Get to your first successful API call for each Velma-2 model in about 5 minutes.
- [Support](https://docs.modulate.ai/support.md): How to reach the Modulate team for technical questions, bug reports, feature requests, or limit increases.
- [Best practices & what to avoid](https://docs.modulate.ai/velma/behaviors/best-practices.md): How to write behavior descriptions that produce consistent, accurate detection results — and the common patterns that cause false positives and missed detections.
- [Custom behaviors](https://docs.modulate.ai/velma/behaviors/custom-behaviors.md): Define your own behavior from scratch, or adapt a pre-built behavior's language for your specific context.
- [Using behaviors](https://docs.modulate.ai/velma/behaviors/using-behaviors.md): How to retrieve the preset catalog, apply preset slugs, and include BehaviorDef objects in your BatchConfig.
- [What are behaviors?](https://docs.modulate.ai/velma/behaviors/what-are-behaviors.md): Behaviors are the signals you tell Velma to listen for. Each one is a named, described detection target that Velma evaluates against the conversation audio.
- [Capabilities](https://docs.modulate.ai/velma/capabilities.md): A complete reference for the Velma-2 batch and streaming endpoints — configuration, all outputs, and how the analysis fits together.
- [What is Velma?](https://docs.modulate.ai/velma/overview.md): Velma-2 is an audio-native voice intelligence model over REST or WebSocket.
- [Playbooks](https://docs.modulate.ai/velma/playbooks.md): End-to-end configuration guides for common Velma-2 use cases — showing how to combine conversation types, participant roles, and behaviors into production-ready analysis pipelines.
- [Call center fraud detection & SOP compliance](https://docs.modulate.ai/velma/playbooks/call-center-fraud.md): Turn your SOPs into Velma behaviors that monitor every call in real time — detecting adversarial caller tactics and agent deviation from the procedures that keep credentials secure and CSAT high.
- [Sales QA and call coaching at scale](https://docs.modulate.ai/velma/playbooks/sales-qa-coaching.md): Post-call analysis that surfaces coaching signals, commitment indicators, and deal health — automatically, across every recording, without a human QA team reviewing each one.
- [Real-time trust & safety for live social audio](https://docs.modulate.ai/velma/playbooks/trust-and-safety.md): Deploy Velma's full safety behavior catalog against live voice chat — and layer platform-specific rules on top — to monitor conversations at a scale no human review team can match.

## OpenAPI Specs

- [velma_2_stt_batch_english_vfast](https://docs.modulate.ai/api/velma_2_stt_batch_english_vfast.yaml)
- [velma_2_language_detection_batch](https://docs.modulate.ai/api/velma_2_language_detection_batch.yaml)
- [velma_2_batch](https://docs.modulate.ai/api/velma_2_batch.yaml)
- [language_detection_batch_openapi](https://docs.modulate.ai/api/language_detection_batch_openapi.yaml)
- [velma_2_synthetic_voice_detection_batch](https://docs.modulate.ai/api/velma_2_synthetic_voice_detection_batch.yaml)
- [velma_2_stt_batch](https://docs.modulate.ai/api/velma_2_stt_batch.yaml)
- [velma_2_pii_phi_redaction_batch](https://docs.modulate.ai/api/velma_2_pii_phi_redaction_batch.yaml)
- [velma_2_music_detection_batch](https://docs.modulate.ai/api/velma_2_music_detection_batch.yaml)
- [music_detection_batch_openapi](https://docs.modulate.ai/api/music_detection_batch_openapi.yaml)
- [music_detection_streaming_openai](https://docs.modulate.ai/api/music_detection_streaming_openai.yaml)
- [velma-2-synthetic-voice-detection-batch-openapi](https://docs.modulate.ai/api/velma-2-synthetic-voice-detection-batch-openapi.yaml)
- [velma-2-stt-batch-openapi](https://docs.modulate.ai/api/velma-2-stt-batch-openapi.yaml)
- [velma-2-stt-batch-english-vfast-openapi](https://docs.modulate.ai/api/velma-2-stt-batch-english-vfast-openapi.yaml)
- [velma-2-pii-phi-redaction-batch-openapi](https://docs.modulate.ai/api/velma-2-pii-phi-redaction-batch-openapi.yaml)
- [openapi](https://docs.modulate.ai/api/openapi.json)

## AsyncAPI Specs

- [velma_2_stt_streaming_english_v2](https://docs.modulate.ai/api/velma_2_stt_streaming_english_v2.yaml)
- [velma_2_streaming](https://docs.modulate.ai/api/velma_2_streaming.yaml)
- [velma_2_synthetic_voice_detection_streaming](https://docs.modulate.ai/api/velma_2_synthetic_voice_detection_streaming.yaml)
- [velma_2_stt_streaming](https://docs.modulate.ai/api/velma_2_stt_streaming.yaml)
- [velma_2_pii_phi_redaction_streaming](https://docs.modulate.ai/api/velma_2_pii_phi_redaction_streaming.yaml)
- [velma_2_music_detection_streaming](https://docs.modulate.ai/api/velma_2_music_detection_streaming.yaml)
- [music_detection_streaming_openai](https://docs.modulate.ai/api/music_detection_streaming_openai.yaml)
- [velma-2-synthetic-voice-detection-streaming-openapi](https://docs.modulate.ai/api/velma-2-synthetic-voice-detection-streaming-openapi.yaml)