# Amplifier Health Developer Hub > Voice biomarker API for behavioral, cognitive, metabolic, and respiratory health signals. The API analyzes voice recordings and returns structured signals (scores, levels, recommended actions) usable in clinical and wellness workflows. ## Curated overviews - [User Guide](https://docs.amplifierhealth.com/user-guide.md): Concise, AI-agent-friendly guide for building applications against the v2 API. - [API Reference](https://docs.amplifierhealth.com/api-reference.md): Concise, AI-agent-friendly reference for v2 endpoints, schemas, and error codes. ## API Reference - [Error Reference](https://docs.amplifierhealth.com/api-reference/error-reference.md): Error codes, error response JSON object, and retry guidance for the API. - [Levels & Actions](https://docs.amplifierhealth.com/api-reference/levels-actions.md): Signal level definitions and recommended action trigger logic for the API response. - [Model API](https://docs.amplifierhealth.com/api-reference/models-api.md): List available models, get model details, and submit audio for model analysis. - [Model IDs Reference](https://docs.amplifierhealth.com/api-reference/models.md): All available voice biomarker sign IDs, evidence tiers, and which named model bundles include each sign. - [API Overview](https://docs.amplifierhealth.com/api-reference/overview.md): Base URL, authentication, and limits for the Amplifier Health Voice Biomarker API. - [Quick Start](https://docs.amplifierhealth.com/api-reference/quick-start.md): A complete working example: submit audio to the apex model and retrieve structured signal results. - [Jobs](https://docs.amplifierhealth.com/api-reference/results.md): Retrieve V2 analysis jobs — paginated list or individual job by ID. - [Response Schema](https://docs.amplifierhealth.com/api-reference/schema.md): Complete reference for the API response structure: model response (summary, signals array) and sign response (signal object). - [Sign API](https://docs.amplifierhealth.com/api-reference/signs-api.md): List available signs, get sign details, and submit audio for sign analysis. - [v2 API — Account](https://docs.amplifierhealth.com/api-reference/v2-account.md): Webhook configuration and credits for the v2 API. ## Guides - [Audio Requirements](https://docs.amplifierhealth.com/guides/audio-requirements.md): Supported formats, duration, sample rate, encoding, and recording environment guidelines for the Amplifier Health API. - [Billing & Cost](https://docs.amplifierhealth.com/guides/billing-and-cost.md): How audio tokens map to API usage and example costs for model, sign, and diarized requests. - [Interpreting Results](https://docs.amplifierhealth.com/guides/interpreting-results.md): Understand the structure of API responses, signal levels, recommended actions, and display rules for clinical and patient-facing UIs. - [Introduction](https://docs.amplifierhealth.com/guides/introduction.md): What the Amplifier Health voice biomarker API does, the two v2 analyze endpoints, job flow, and concepts you need to integrate. - [MCP Server](https://docs.amplifierhealth.com/guides/mcp.md): Connect any MCP-compatible AI client to the Amplifier Health voice biomarker API using the hosted Streamable-HTTP MCP server. - [Signs](https://docs.amplifierhealth.com/guides/models-all.md): Voice biomarker signs: established, emerging, and investigational — with evidence tiers, acoustic indicators, and detection rationale. - [Signs — Overview](https://docs.amplifierhealth.com/guides/models.md): Voice biomarker signs: evidence tiers, routing context, and which named model bundles include each sign. - [Production Checklist](https://docs.amplifierhealth.com/guides/production-checklist.md): Pre-deployment checklist for integrations going to production with the Amplifier Health API. - [Models](https://docs.amplifierhealth.com/guides/use-cases-all.md): Named model bundles for clinical and wellness contexts — signs, evidence tiers, and usage scenarios. - [Models — Overview](https://docs.amplifierhealth.com/guides/use-cases.md): Named model bundles for clinical and wellness contexts — available models, sign composition, and how to choose. - [Wellness Metrics](https://docs.amplifierhealth.com/guides/wellness-all.md): All 28 wellness metrics in five domains: mood & affect, arousal & tension, energy & fatigue, cognitive & behavioral, personality & social. - [Wellness Metrics — Overview](https://docs.amplifierhealth.com/guides/wellness.md): Acoustic wellness metrics: score interpretation and the full reference of 28 wellness metrics plus 3 VAD (Valence, Arousal, Dominance) dimensions. ## Optional - [Full corpus (llms-full.txt)](https://docs.amplifierhealth.com/llms-full.txt): All v2 pages concatenated into one file for offline ingestion.