PatterAI/Patter

Open-source voice-AI SDK. The Vapi/Retell alternative for builders who want to own the stack. Give your AI agent a phone number in 4 lines — Python and TypeScript, MIT licensed, Twilio, Telnyx, and Plivo.

Python

1,075

159 commits

updated Oct 3, 2026

See the code

README

Patter SDK

Patter SDK

PyPI npm MIT License Python 3.11+ TypeScript 5+

About • How It Works • Documentation • Quickstart • Skills • Templates


About

Patter is the open-source SDK that gives your AI agent a phone number. You build the agent; Patter handles everything between it and the phone network — the agent loop, the language model, speech-to-text, text-to-speech, real-time voice, audio processing, and the telephony carrier.

  • Build with one API in Python or TypeScript — same surface, same hooks, same events, at full parity.
  • Choose the provider for every layer — LLM, STT, TTS, realtime engine, carrier — and swap any of them with one line.
  • Run locally with a built-in tunnel and dashboard, or simulate a whole call from your terminal — no phone required.

How It Works

Patter is the full voice stack between your application and the phone network — not just glue between an LLM and a carrier. It runs the agent loop and owns every layer of the call, and you pick the provider for each one. Compose them in Realtime, Pipeline, or Hybrid mode.

27+ provider integrations across the voice stack · 3 voice modes · 2 SDKs (Python & TypeScript) at parity.

LayerChoose from
LLM — text generationOpenAI · Anthropic · Google Gemini · Groq · Cerebras
STT — speech-to-textDeepgram · AssemblyAI · Cartesia · Soniox · Speechmatics · Whisper · Fish Audio
TTS — text-to-speechElevenLabs · OpenAI · Cartesia · LMNT · Rime · Telnyx · Fish Audio
Realtime — all-in-one voiceOpenAI Realtime · Gemini Live · Ultravox · ElevenLabs ConvAI
Telephony — phone carriersTwilio · Telnyx · Plivo
Audio — VAD & suppressionSilero VAD · Krisp · DeepFilterNet

On top of the stack: an automatic LLM fallback chain (provider failover mid-call), built-in tools / call transfer / guardrails that behave identically on every carrier, and a vendor-neutral OpenTelemetry trace of each call.

Documentation

Visit the docs, or jump straight to a quickstart: TypeScript · Python.

Skills for Coding Agents

Using Claude Code, Claude Desktop, OpenClaw, Hermes, Cursor, Codex, or another AI coding agent?

Install Patter skills for voice agents →

npx skills add patterai/skills

The bundle works in ~55 agent harnesses that consume the Anthropic Agent Skills standard. Install once; every agent on your machine learns the SDK. Skills live in their own repository: PatterAI/skills.

Quickstart

Provider and carrier credentials are read from environment variables (e.g. TWILIO_ACCOUNT_SID, OPENAI_API_KEY) — the docs list the full catalog. Swap Twilio for Telnyx or Plivo to change carrier.

TypeScript

npm install getpatter
import { Patter, Twilio, OpenAIRealtime } from "getpatter";

const phone = new Patter({ carrier: new Twilio(), phoneNumber: "+15550001234" });
const agent = phone.agent({
  engine: new OpenAIRealtime(),
  systemPrompt: "You are a friendly receptionist for Acme Corp.",
  firstMessage: "Hello! How can I help?",
});
await phone.serve({ agent, tunnel: true });

Python

pip install getpatter
from getpatter import Patter, Twilio, OpenAIRealtime

phone = Patter(carrier=Twilio(), phone_number="+15550001234")
agent = phone.agent(
    engine=OpenAIRealtime(),
    system_prompt="You are a friendly receptionist for Acme Corp.",
    first_message="Hello! How can I help?",
)
await phone.serve(agent, tunnel=True)

tunnel: true spawns a Cloudflare quick tunnel and points your number at it — ideal for local dev. For production, use a static webhook_url (or ngrok); see Tunneling.

Telemetry

Note Patter collects anonymous, opt-out usage data (SDK version, bucketed provider/model and call facts) to help us prioritise — never call content, prompts, phone numbers, keys, or free text.

Opt out any time: Patter(telemetry=False) (new Patter({ telemetry: false })), getpatter telemetry disable, or PATTER_TELEMETRY_DISABLED=1 (also honours DO_NOT_TRACK=1); auto-off in CI/tests. Inspect without sending: PATTER_TELEMETRY_DEBUG=1. Full details: Telemetry.

Templates

Each template is a self-contained repo — clone, add your .env, and run. Python and TypeScript both included.

TemplateDescriptionRepo
Inbound AgentAnswer calls as a restaurant booking assistantpatter-inbound-agent
Outbound CallsPlace calls with AMD and voicemail droppatter-outbound-calls
Tool CallingCRM lookup + ticket creation via webhook toolspatter-tool-calling
Custom VoicePipeline mode: Deepgram STT + ElevenLabs TTSpatter-custom-voice
Dynamic VariablesPersonalize prompts per caller using CRM datapatter-dynamic-variables
Custom LLMBring your own modelpatter-custom-llm
DashboardReal-time monitoring with cost + latency trackingpatter-dashboard
Production SetupEverything enabled: tools, guardrails, recording, dashboardpatter-production
git clone https://github.com/PatterAI/patter-inbound-agent
cd patter-inbound-agent
cp .env.example .env    # fill in your keys
cd python && pip install -r requirements.txt && python main.py

Star History

Star History Chart

Contributors

Thanks to all our amazing contributors!

License

MIT — see LICENSE.

ai-agent
ai-phone-agent
hermes-agent
llm
mastra
openai
openclaw
open-source
python
realtime-api
sdk
speech-to-text
telnyx
text-to-speech
twilio
typescript
vapi-alternative
voice-agent
voice-ai
voicebot

PatterAI/Patter

Open-source voice-AI SDK. The Vapi/Retell alternative for builders who want to own the stack. Give your AI agent a phone number in 4 lines — Python and TypeScript, MIT licensed, Twilio, Telnyx, and Plivo.

Python

1,075

159 commits

updated Oct 3, 2026

See the code

README

Patter SDK

Patter SDK

PyPI npm MIT License Python 3.11+ TypeScript 5+

About • How It Works • Documentation • Quickstart • Skills • Templates


About

Patter is the open-source SDK that gives your AI agent a phone number. You build the agent; Patter handles everything between it and the phone network — the agent loop, the language model, speech-to-text, text-to-speech, real-time voice, audio processing, and the telephony carrier.

  • Build with one API in Python or TypeScript — same surface, same hooks, same events, at full parity.
  • Choose the provider for every layer — LLM, STT, TTS, realtime engine, carrier — and swap any of them with one line.
  • Run locally with a built-in tunnel and dashboard, or simulate a whole call from your terminal — no phone required.

How It Works

Patter is the full voice stack between your application and the phone network — not just glue between an LLM and a carrier. It runs the agent loop and owns every layer of the call, and you pick the provider for each one. Compose them in Realtime, Pipeline, or Hybrid mode.

27+ provider integrations across the voice stack · 3 voice modes · 2 SDKs (Python & TypeScript) at parity.

LayerChoose from
LLM — text generationOpenAI · Anthropic · Google Gemini · Groq · Cerebras
STT — speech-to-textDeepgram · AssemblyAI · Cartesia · Soniox · Speechmatics · Whisper · Fish Audio
TTS — text-to-speechElevenLabs · OpenAI · Cartesia · LMNT · Rime · Telnyx · Fish Audio
Realtime — all-in-one voiceOpenAI Realtime · Gemini Live · Ultravox · ElevenLabs ConvAI
Telephony — phone carriersTwilio · Telnyx · Plivo
Audio — VAD & suppressionSilero VAD · Krisp · DeepFilterNet

On top of the stack: an automatic LLM fallback chain (provider failover mid-call), built-in tools / call transfer / guardrails that behave identically on every carrier, and a vendor-neutral OpenTelemetry trace of each call.

Documentation

Visit the docs, or jump straight to a quickstart: TypeScript · Python.

Skills for Coding Agents

Using Claude Code, Claude Desktop, OpenClaw, Hermes, Cursor, Codex, or another AI coding agent?

Install Patter skills for voice agents →

npx skills add patterai/skills

The bundle works in ~55 agent harnesses that consume the Anthropic Agent Skills standard. Install once; every agent on your machine learns the SDK. Skills live in their own repository: PatterAI/skills.

Quickstart

Provider and carrier credentials are read from environment variables (e.g. TWILIO_ACCOUNT_SID, OPENAI_API_KEY) — the docs list the full catalog. Swap Twilio for Telnyx or Plivo to change carrier.

TypeScript

npm install getpatter
import { Patter, Twilio, OpenAIRealtime } from "getpatter";

const phone = new Patter({ carrier: new Twilio(), phoneNumber: "+15550001234" });
const agent = phone.agent({
  engine: new OpenAIRealtime(),
  systemPrompt: "You are a friendly receptionist for Acme Corp.",
  firstMessage: "Hello! How can I help?",
});
await phone.serve({ agent, tunnel: true });

Python

pip install getpatter
from getpatter import Patter, Twilio, OpenAIRealtime

phone = Patter(carrier=Twilio(), phone_number="+15550001234")
agent = phone.agent(
    engine=OpenAIRealtime(),
    system_prompt="You are a friendly receptionist for Acme Corp.",
    first_message="Hello! How can I help?",
)
await phone.serve(agent, tunnel=True)

tunnel: true spawns a Cloudflare quick tunnel and points your number at it — ideal for local dev. For production, use a static webhook_url (or ngrok); see Tunneling.

Telemetry

Note Patter collects anonymous, opt-out usage data (SDK version, bucketed provider/model and call facts) to help us prioritise — never call content, prompts, phone numbers, keys, or free text.

Opt out any time: Patter(telemetry=False) (new Patter({ telemetry: false })), getpatter telemetry disable, or PATTER_TELEMETRY_DISABLED=1 (also honours DO_NOT_TRACK=1); auto-off in CI/tests. Inspect without sending: PATTER_TELEMETRY_DEBUG=1. Full details: Telemetry.

Templates

Each template is a self-contained repo — clone, add your .env, and run. Python and TypeScript both included.

TemplateDescriptionRepo
Inbound AgentAnswer calls as a restaurant booking assistantpatter-inbound-agent
Outbound CallsPlace calls with AMD and voicemail droppatter-outbound-calls
Tool CallingCRM lookup + ticket creation via webhook toolspatter-tool-calling
Custom VoicePipeline mode: Deepgram STT + ElevenLabs TTSpatter-custom-voice
Dynamic VariablesPersonalize prompts per caller using CRM datapatter-dynamic-variables
Custom LLMBring your own modelpatter-custom-llm
DashboardReal-time monitoring with cost + latency trackingpatter-dashboard
Production SetupEverything enabled: tools, guardrails, recording, dashboardpatter-production
git clone https://github.com/PatterAI/patter-inbound-agent
cd patter-inbound-agent
cp .env.example .env    # fill in your keys
cd python && pip install -r requirements.txt && python main.py

Star History

Star History Chart

Contributors

Thanks to all our amazing contributors!

License

MIT — see LICENSE.

ai-agent
ai-phone-agent
hermes-agent
llm
mastra
openai
openclaw
open-source
python
realtime-api
sdk
speech-to-text
telnyx
text-to-speech
twilio
typescript
vapi-alternative
voice-agent
voice-ai
voicebot

Project health

Latest release

0.0.1 · Apr 13, 2026

Releases this year

1

Significant stargazers

Peter Goldstein

153 followers · starred May 2026

svjack

102 followers · starred May 2026

Palash Debnath

1,085 followers · starred Jun 2026

Javi

1,125 followers · starred May 2026