{Tech: Europe} Paris AI Hackathon

Welcome to the {Tech: Europe} Paris AI Hackathon! We brought voice AI APIs and Lego boxes. You bring the ideas. The SLNG team is here all weekend. Come say hi, grab a sticker, ask us anything.

Look for Ismael Ordaz (founder) and Nicolas Grenié (DevRel) — they’re around all weekend and happy to help you build.

What is SLNG?

SLNG is one API for real-time speech. Text-to-Speech, Speech-to-Text, and Voice Agents, all under 200ms. We aggregate providers like Deepgram, Rime, Cartesia, and Kugel behind a single endpoint. You switch models by changing the URL, not your code.

Text-to-Speech

Text in, audio out. Multiple voices and languages.

Speech-to-Text

Transcribe audio files or live streams.

Voice Agents

Full voice agents that make and receive phone calls.

Get your API key

Create an account

Generate an API key

Go to the API Keys page in your dashboard and create a new key. Copy it somewhere safe — you won’t be able to see it again.

Test it

Run this in your terminal to make sure everything works:

curl https://api.slng.ai/v1/bridges/unmute/tts/slng/deepgram/aura:2-en \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text": "Hello from Paris!"}' \
  --output hello.wav

You should get a hello.wav audio file. If you hear “Hello from Paris!” — you’re all set.

Start building

Grab the code for whatever you need.

Text-to-Speech
Speech-to-Text
Voice Agents
Unified API

Send text, get audio back.

# Change this to swap models (e.g. slng/rime/arcana:3-en, slng/rime/arcana:3-es)
MODEL="slng/deepgram/aura:2-en"

curl "https://api.slng.ai/v1/bridges/unmute/tts/${MODEL}" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Hello from Paris!"
  }' \
  --output hello.wav

Pick a different voice by adding "voice": "aura-2-theia-en" to the request body. See all available voices.

Other languages

Switch the model in the URL — the rest of the code is identical. Spanish via Rime Arcana v3:

curl https://api.slng.ai/v1/bridges/unmute/tts/slng/rime/arcana:3-es \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text": "¡Hola desde París!"}' \
  --output hola.wav

Spanish, Hindi, English (HTTP): slng/rime/arcana:3-es, slng/rime/arcana:3-hi, slng/rime/arcana:3-en
French (WebSocket only): Cartesia Sonic 3 or Kugel

See the Models page for the full language matrix.

Upload an audio file and get a transcription back.

# Change this to swap models (e.g. slng/deepgram/nova:3-multi for multilingual, soniox/soniox:latest)
MODEL="slng/deepgram/nova:3-en"

curl "https://api.slng.ai/v1/bridges/unmute/stt/${MODEL}" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -F "audio=@recording.wav"

Transcribing French, Spanish, or mixed-language audio? Switch the model to slng/deepgram/nova:3-multi — same code, auto-detects across 10+ languages.Need real-time transcription? Check out the WebSocket STT examples.

Voice Agents pair an LLM with STT and TTS so you get a full conversational agent that can take and make phone calls or run in a browser. Create one through the Agent Studio UI or via the API.You pick the models, write a system prompt, and optionally add tools (webhooks to your backend, hangup, human transfer, date/time lookup). The agent handles the rest.

curl -X POST https://api.agents.slng.ai/v1/agents \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Hackathon Demo Agent",
    "system_prompt": "You are a helpful assistant at a hackathon. Keep responses short, one or two sentences. Be friendly and direct.",
    "greeting": "Hey! I am your hackathon assistant. What can I help you with?",
    "language": "en",
    "models": {
      "stt": "slng/deepgram/nova:3-en",
      "llm": "groq/moonshotai/kimi-k2-instruct-0905",
      "tts": "slng/deepgram/aura:2-en",
      "tts_voice": "aura-2-thalia-en"
    },
    "tools": [
      {
        "type": "template",
        "id": "hangup-tool",
        "template": "hangup",
        "execution_policy": {
          "pre_action_message": { "enabled": true, "text": "Good luck with your project!" }
        }
      }
    ],
    "region": "eu-central",
    "slng_api_key": "YOUR_API_KEY"
  }'

You can also skip the API and build your agent visually in Agent Studio, then test it right in the browser.Want to go further? Add webhook tools to connect your agent to external APIs, or use template variables to make prompts dynamic. See the full Voice Agents guide.

All the TTS and STT examples above go through the Unified API. One endpoint covers every provider, and you swap a model by changing the URL. Handy when you want to try multiple providers without writing a different integration for each one.

https://api.slng.ai/v1/bridges/unmute/{stt|tts}/{provider}/{model}:{variant}

The bridges/unmute/ path segment is the legacy route name — same endpoint, same Unified API. Works over both HTTP and WebSocket on the same URL.Need fine-grained control over a specific provider’s features? Call each model directly.See the full Unified API documentation.

Try it live

Not ready to write code yet? Try the demos in your browser — drop in your API key and go.

Live TTS demo

Type something and hear it back. Try different models and voices.

Live STT demo

Speak into your mic and watch the transcription stream in.

Source code: github.com/slng-ai/examples

What we want you to build

Use voice and speech AI in whatever way gets you excited. Here are some starting points, but go wherever the idea takes you.

Voice assistants

An agent that books appointments, handles support, tutors students. Pick a task and nail it.

Accessibility tools

Speech interfaces, screen readers, audio descriptions. Make something more people can use.

Creative audio apps

Podcasts, storytelling, audio games, voice-driven art. Surprise us.

Real-time transcription

Live captioning, meeting notes, multilingual translation. Turn speech into something useful.

Prizes

Best overall project wins a Lego Star Wars set. Demo what you built, impress the judges, take home some bricks.

FAQ

How much API credit do I get?

€4 in free credits when you sign up. That covers roughly 80 hours of audio generation or transcription, so you won’t run out this weekend.

What if I run out of credits?

Come find us at the event. We’ll top you up.

Do my credits expire?

Nope. Keep building after the hackathon, polish your project, start a new one. They’re yours.

Which models should I use?

For most projects, start with:

English TTS: slng/deepgram/aura:2-en — low latency
English STT: slng/deepgram/nova:3-en — high accuracy
Spanish or Hindi TTS: slng/rime/arcana:3-es, slng/rime/arcana:3-hi
French TTS (WebSocket only): Cartesia Sonic 3 or Kugel
Multilingual STT: slng/deepgram/nova:3-multi — auto-detects 10+ languages

Full catalog on the Models page.

Can I use SLNG with my favorite framework?

Yes. It’s standard HTTP and WebSocket, so it works with anything. The Unified API follows the same URL pattern for every provider, so you can drop SLNG into an existing voice pipeline without rewriting your integration.

Do I need a paid account?

No. Sign up at app.slng.ai and you’re good to go. The free tier covers the whole hackathon.

Where can I get help?

Find us at the event, we’re around all weekend. You can also check the full docs.

Getting Started

SDKs & Tools

Dashboard

Guides

Voices

Examples

Changelog

What is SLNG?

Text-to-Speech

Speech-to-Text

Voice Agents

Get your API key

Start building

Other languages

Try it live

Live TTS demo

Live STT demo

What we want you to build

Voice assistants

Accessibility tools

Creative audio apps

Real-time transcription

Prizes

FAQ

Getting Started

SDKs & Tools

Dashboard

Guides

Voices

Examples

Changelog

Documentation Index

​What is SLNG?

Text-to-Speech

Speech-to-Text

Voice Agents

​Get your API key

​Start building

​Other languages

​Try it live

Live TTS demo

Live STT demo

​What we want you to build

Voice assistants

Accessibility tools

Creative audio apps

Real-time transcription

​Prizes

​FAQ

What is SLNG?

Get your API key

Start building

Other languages

Try it live

What we want you to build

Prizes

FAQ