Build with Sunesis
Build real-time characters, expressive voices, and capable agents from one platform.
Sunesis is the character, voice, video, and conversation layer for AI. Every capability is available three ways: in the Studio (no code), through the REST API, and via the official SDKs.
Authenticate every request with a bearer token in the Authorization header. Keys are issued from your dashboard, create a free account to generate one (free tier included, no card required).
Quickstart
Make your first request
Create a key in the dashboard, send one request, and receive audio back. Start with the language your team already uses.
curl https://api.sunesis.ai/v1/voice/generate \
-H "Authorization: Bearer $SUNESIS_KEY" \
-H "Content-Type: application/json" \
-d '{ "voice": "aria", "text": "Hello from Sunesis." }'Character generation
Create the person behind the conversation
A Sunesis character combines a visual presence, a signature voice, and an agent persona. Start from a preset or build a reusable character for your product.
Shape the presence
Choose a natural, stylized, or brand-led visual direction for the screen.
Give it a voice
Pair the character with a Sunesis voice or a consented voice clone.
Connect its mind
Attach an agent persona, memory, and the tools it needs to be useful.
Ready to design your first real-time character?
Open Character StudioVoice
Speech that sounds human
Synthesize, transcribe, clone, and stream speech, the voice building blocks behind every Sunesis product.
Capability guide
Text to Speech
Generate expressive spoken audio from plain text for narration, product UX, and a character's spoken turn.
What to configure
- The text to speak and its intended language
- A voice or approved clone
- Delivery controls such as pace, expression, and audio format
Implementation flow
- 1Create or select a voice in Studio
- 2Send text to the voice generation endpoint
- 3Stream playback immediately or store the returned audio with your asset
Production note. Keep the text you send concise for conversational turns. For long-form work, split at natural sentence boundaries and preserve the order in your own queue.
Open productCapability guide
Speech to Text
Turn recorded or live speech into structured text your product can search, summarize, or route to an agent.
What to configure
- An audio or video file, or an incoming live audio stream
- Optional language and vocabulary context
- Whether your downstream system needs timestamps or speaker turns
Implementation flow
- 1Upload audio or connect the stream
- 2Request a transcript with the metadata you need
- 3Store the transcript alongside the original session or hand it to an agent
Production note. Treat transcription as an event in your workflow. Persist segment and speaker metadata so reviews, corrections, and handoffs remain traceable.
Open productCapability guide
Voice Cloning
Create a reusable voice identity from a clearly consented recording for a person, brand, or approved performer.
What to configure
- A clean, consented recording
- Voice ownership and usage approval
- A name and description your workspace can recognize
Implementation flow
- 1Collect and verify consent before upload
- 2Create the voice in Studio
- 3Review a short test script before using the voice in a production flow
Production note. Build consent into the product flow, not a later review. Keep the original approval and the clone's intended use attached to the project record.
Open productCapability guide
Realtime Streaming
Use bidirectional streaming to make spoken experiences feel immediate in a call, a live agent, or an on-screen character.
What to configure
- A client audio source or text stream
- A selected voice and session context
- Your interruption, buffering, and reconnect rules
Implementation flow
- 1Open a session before the user speaks
- 2Send partial input as it arrives
- 3Play returned chunks incrementally and stop cleanly when the user interrupts
Production note. Design for interruption first. A great real-time experience stops, listens, and recovers without replaying stale audio to the user.
Open productVideo
Faces that speak
Turn a script into a talking digital character, generate scenes from a prompt, or train a reusable avatar.
Capability guide
Talking Avatars
Render an on-screen speaker that turns a voice or script into a responsive, lip-synced visual conversation.
What to configure
- A character or approved visual preset
- Spoken audio or a script and voice
- The destination aspect ratio and playback context
Implementation flow
- 1Choose a character in Character Studio
- 2Connect its voice and agent persona
- 3Launch it in your product's call or presentation surface
Production note. Match the visual presence to the user's task. High-trust support and training use cases benefit from restrained framing and clear disclosure.
Open productCapability guide
Video Generation
Produce generated video scenes for product storytelling, campaigns, and character-led creative work.
What to configure
- A scene brief with subject, setting, and action
- An aspect ratio and delivery format
- Optional brand, character, or reference direction
Implementation flow
- 1Draft the scene in Studio
- 2Generate an initial take and review the result
- 3Export approved shots or combine them with voice and character layers
Production note. Use short, intentional scene briefs. Treat every generated take as a reviewable asset before it reaches a public audience.
Open productCapability guide
Custom Avatars
Create a repeatable visual persona for a specific person or brand instead of selecting a general-purpose preset.
What to configure
- A properly authorized reference capture
- A character name and intended product role
- A review workflow for test conversations
Implementation flow
- 1Capture approved reference material
- 2Configure the character in Studio
- 3Run voice and video previews before assigning the persona to a live agent
Production note. Keep custom character access scoped to the people who need it. Establish an approval step for changes to appearance, voice, or knowledge.
Open productConversation
Agents that listen and reply
Give agents a persona, memory, and tools, then talk to them over text, voice, or video.
Capability guide
Agents
Build an agent that can speak, listen, remember the current session, and take action through the tools you connect.
What to configure
- A role, operating instructions, and opening message
- A knowledge source or approved context
- The functions the agent is allowed to call
Implementation flow
- 1Define a persona with a clear job
- 2Connect knowledge and tools
- 3Test the full conversation path with expected and edge-case questions
Production note. Give each agent one clear responsibility. Route complex or sensitive requests to a human instead of expanding a single agent beyond a safe scope.
Open productCapability guide
Memory & Sessions
Maintain useful context between turns so the user does not have to repeat their goal, preferences, or previous answer.
What to configure
- A session identifier from your application
- The context that should persist
- Retention and deletion rules appropriate to the experience
Implementation flow
- 1Create a session when a conversation begins
- 2Attach relevant context on each turn
- 3Close or clear the session according to your product's policy
Production note. Store only the context that makes the next response better. Give users a clear path to restart or remove a conversation when that is appropriate.
Open productCapability guide
Tools & Actions
Let an agent move beyond conversation by calling your own verified services, from account lookups to appointment booking.
What to configure
- A narrowly scoped function schema
- Validated parameters and a trusted backend
- A user-facing response for success and failure
Implementation flow
- 1Describe the action and its required fields
- 2Validate the request on your server
- 3Return a concise result the agent can explain to the user
Production note. Do not give an agent direct authority over sensitive actions. Put validation, permissions, and audit logging behind every tool call.
Open productModels
The models behind each interaction
Select the right surface for the moment. Sunesis handles the real-time infrastructure underneath.
The flagship text-to-speech model, expressive, multilingual, and quick to first byte (~180ms).
Speech recognition with diarization, timestamps, and strong accuracy on noisy, real-world audio.
Generates talking-head video and trains custom avatars from a short reference clip.
The reasoning model behind agents, with tool use and memory that persists across sessions.
Cross-lingual dubbing that keeps the original speaker's voice, timing, and emotion intact.
Ways to build
Choose the path that fits your team
Use Studio for a fast prototype, then bring the same primitives into your product with the SDKs or API.
Capability guide
Web App
Use Sunesis Studio to prototype a complete voice, video, or character flow before you commit it to code.
What to configure
- A product goal or conversation brief
- The voices, characters, or media assets to explore
- A small test script or scenario
Implementation flow
- 1Create the experience in Studio
- 2Preview it with real prompts and controls
- 3Carry the chosen configuration into your application integration
Production note. Use Studio as the shared review space between product, design, and engineering. Ship only the settings your team has tested together.
Open productCapability guide
SDKs
Use the official SDKs when you want typed requests, clear integration patterns, and a straightforward upgrade path.
What to configure
- A server-side Sunesis API key
- Your chosen language runtime
- A place to store generated media or session state
Implementation flow
- 1Install the SDK for your runtime
- 2Initialize it with a server-held key
- 3Call the product primitive and handle the result in your own application
Production note. Never place long-lived API keys in a browser bundle. Keep credentials on your server and issue your client only the access it needs.
Open productCapability guide
REST API
Use the REST API when you need direct control over HTTP requests, webhooks, or an integration language without an SDK.
What to configure
- A bearer token from your workspace
- A JSON request body for the selected product primitive
- Your own timeout, retry, and idempotency strategy
Implementation flow
- 1Authenticate with a server-side bearer token
- 2Send a focused request to the relevant endpoint
- 3Persist the result or stream it into the next stage of your workflow
Production note. Log request identifiers and outcomes, not sensitive customer content. Add retry behavior only where repeating the operation is safe.
Open productCapability guide
MCP Server
Connect Sunesis capabilities to an MCP-compatible development environment so your team can explore and automate the platform from its tools.
What to configure
- An approved MCP client
- A scoped workspace credential
- A clear set of actions the client is permitted to perform
Implementation flow
- 1Add the Sunesis MCP connection
- 2Authenticate with a limited-scope credential
- 3Use tool calls to inspect, prototype, and document your integration
Production note. Use separate credentials for development and production. Review the tools exposed to each environment before granting a team-wide connection.
Open productOperations
Run Sunesis with confidence
Controls for the team that owns the integration: keys, usage visibility, and enterprise safeguards.
Keep generation spend visible
See workspace credits, compare production needs, and choose the plan that matches your character, voice, and agent volume.
View pricingScale with clear controls
Give teams the access and operational support they need when real-time AI becomes part of a customer-facing workflow.
Explore enterpriseNext steps
Continue building
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