Fixa.dev
Fixa.dev is an open-source Python platform for testing, evaluating, and monitoring AI voice agents through automated simulated calls and real-time production analysis.
https://fixa.dev/?ref=producthunt
Product Information
Updated:Apr 20, 2026
What is Fixa.dev
Fixa.dev is a comprehensive testing and monitoring solution specifically designed for AI voice agent developers. Created by former PlayHT voice agent developers, Fixa addresses the challenge of manually testing voice agents by providing automated testing capabilities and production call monitoring. The platform is fully open-source and offers a Python package (fixa-dev) that enables developers to run simulated tests where one AI voice agent calls another, with conversations evaluated by LLMs to identify bugs and performance issues. It supports integration with popular services like Twilio, Deepgram, Cartesia, and OpenAI, making it accessible for developers working with various voice AI technologies.
Key Features of Fixa.dev
Fixa.dev is a comprehensive platform for AI voice agent testing, monitoring, and development. It offers automated testing capabilities using AI voice agents to call and evaluate other voice agents, real-time production call monitoring with metrics like latency and interruptions, and actionable bug detection. The platform is fully open source and provides both local and cloud-based evaluation options. Additionally, Fixa includes a no-code software builder that enables users to create full-stack apps, APIs, and workflows from idea to production without coding.
Automated Voice Agent Testing: Uses AI voice agents to automatically call and test your voice agents, with LLM-powered evaluation of conversation quality and outcomes, eliminating manual testing hours
Real-time Production Monitoring: Monitors latency, interruptions, and correctness of production calls in real-time with customizable Slack alerts for specific metrics or failures
Automated Bug Detection: Automatically identifies bugs in both test and production environments, providing precise and actionable insights with root cause analysis
Open Source Framework: Fully open source Python package (fixa-dev) with integration capabilities for Twilio, Deepgram, Cartesia, and OpenAI, supporting transparent development and community trust
No-Code Software Builder: Enables building full-stack applications, APIs, and workflows from idea to production without requiring coding skills
Flexible Evaluation Options: Offers both LocalEvaluator for development testing and CloudEvaluator for advanced analytics with UI visualization in Fixa Observe
Use Cases of Fixa.dev
Voice Agent Quality Assurance: Software development teams can run automated simulated test scenarios with customizable agent personas to ensure voice agents handle various customer interactions correctly before deployment
Customer Service Performance Monitoring: Enterprises can monitor production voice agent calls in real-time to track key metrics like response latency, conversation interruptions, and successful data collection (e.g., email addresses)
Voice Agent Debugging and Optimization: Developers can identify and fix bugs faster by analyzing detailed call transcripts and automated bug reports, reducing time spent on manual call reviews
Multi-language Voice Agent Testing: Companies operating globally can test voice agents across all languages supported by Deepgram to ensure consistent quality in international markets
Rapid Prototyping for Startups: Tech startups can quickly build and deploy voice-enabled applications and APIs without extensive coding, accelerating time-to-market
Compliance and Quality Alerts: Organizations can set up automated Slack alerts for specific failure conditions or performance thresholds to maintain service level agreements and compliance standards
Pros
Fully open source, promoting transparency, developer trust, and community-driven improvements
Pay-as-you-go pricing model with no demos or commitments, making it accessible for projects of all sizes
Comprehensive testing and monitoring solution that eliminates hours of manual voice agent testing
Seamless integration with popular tools like Twilio, Deepgram, OpenAI, and Slack for easy implementation
Cons
Primarily focused on voice agents, with limited support for text-based chatbots
Requires multiple API keys and services (OpenAI, Deepgram, Cartesia, Twilio, ngrok) for full functionality
May have limitations in advanced features compared to more specialized enterprise testing tools
Requires Python 3.10+ and technical setup knowledge for initial implementation
How to Use Fixa.dev
1: Install the fixa-dev package using pip: pip install fixa-dev
2: Set up required environment variables: OPENAI_API_KEY, DEEPGRAM_API_KEY, CARTESIA_API_KEY, TWILIO_ACCOUNT_SID, TWILIO_AUTH_TOKEN, and NGROK_AUTH_TOKEN
3: Import necessary modules: from fixa import Test, Agent, Scenario, Evaluation, TestRunner; from fixa.evaluators import LocalEvaluator (or CloudEvaluator for UI visualization); from dotenv import load_dotenv; import ngrok, os, asyncio
4: Load environment variables using load_dotenv(override=True)
5: Configure your Twilio phone numbers: set TWILIO_PHONE_NUMBER (the number to initiate calls from, must be owned by you) and PHONE_NUMBER_TO_CALL (your voice agent's phone number)
6: Define a test agent by creating an Agent object with a name and prompt (e.g., Agent(name='jessica', prompt='you are a young woman named jessica...'))
7: Create test scenarios, evaluations, and configure the TestRunner to execute automated voice agent tests
8: Run your tests asynchronously using async/await pattern with the main() function
9: Monitor production calls through fixa observe to track latency (TTFW, p50/p90/p95), interruptions, and correctness metrics
10: Set up Slack alerts for custom notifications when your voice agent encounters issues like high latency or fails to collect required information
11: If using a paid ngrok plan, add your ngrok domain to the listener variable for proper webhook configuration
12: Review test results and call recordings to identify bugs including hallucinations, interruptions, transcription errors, and sentiment errors
Fixa.dev FAQs
Fixa is an AI software builder that helps you build real software from idea to production with no coding required. It can create full-stack apps, APIs, workflows, and more.
Popular Articles
Nano Banana SBTI: What It Is, How It Works, and How to Use It in 2026
Apr 15, 2026
Atoms Review — The AI Product Builder Redefining Digital Creation in 2026
Apr 10, 2026
Kilo Claw: How to Deploy and Use a True "Do‑It‑For‑You" AI Agent(2026 Update)
Apr 3, 2026
OpenAI Shuts Down Sora App: What the Future Holds for AI Video Generation in 2026
Mar 25, 2026
Latest AI Tools Similar to Fixa.dev
ExoTest
ExoTest is an AI-driven product testing platform that connects startups with expert testers in their specific niche to provide comprehensive feedback and actionable insights before product launch.
AI Dev Assess
AI Dev Assess is an AI-powered tool that automatically generates role-specific interview questions and assessment matrices to help HR professionals and technical interviewers evaluate software developer candidates efficiently.
Tyne
Tyne is a professional AI-powered software and consulting company that helps businesses streamline their everyday needs through data analysis, yield improvement systems, and AI solutions.
MTestHub
MTestHub is an all-in-one AI-powered recruitment and assessment platform that streamlines hiring processes with automated screening, skill evaluations, and advanced anti-cheating measures.
Popular AI Tools Like Fixa.dev
Web Accessibility Testing MCP
A11y MCP is a Model Context Protocol server that enables AI language models to perform automated web accessibility testing by integrating with Deque's Axe-core API and Puppeteer to analyze web content for WCAG compliance.
rep+
rep+ is a powerful Chrome DevTools extension that brings Burp Suite Repeater functionality directly into your browser, enabling HTTP request testing, security analysis, and AI-powered attack suggestions without proxy setup.
Gatling AI Assistant for VS Code
Gatling AI Assistant is an AI-powered extension for Visual Studio Code that helps developers create and manage load testing scenarios using Gatling's load testing framework.
KaneAI
KaneAI is the world's first end-to-end AI-powered software testing agent that enables users to create, debug, and evolve tests using natural language.