Businesses use AI voice agents to handle or assist with phone-based interactions such as customer inquiries, appointment scheduling, lead qualification, and routine service requests. Building a reliable voice experience requires expertise across conversational AI, telephony, integrations, and testing. The right AI voice agent developer can help businesses design a system that fits their workflows, customer needs, and existing technology.
What does an AI voice agent developer do?
New An AI voice agent developer builds and integrates systems that use artificial intelligence to conduct spoken conversations over the phone or other voice channels. Depending on the project, they may work with speech recognition, large language models, text-to-speech, technology, voice-agent platforms, telephony services, and business applications. They also design how agents respond, take actions, transfer conversations, and handle situations that require human assistance.
These are typical AI voice agent developer tasks:
- Design conversation flows, prompts, guardrails, fallback behavior, and escalation paths
- Build voice agents using platforms and frameworks such as Vapi, Voiceflow, or other conversational AI tools
- Integrate agents with customer relationship management (CRM) systems, calendars, databases, and APIs so they can retrieve information and complete approved actions
- Connect AI agents with phone systems and telephony providers such as Twilio, Telnyx, or Plivo
- Configure speech recognition and text-to-speech technology for responsive, natural responses
- Test for edge cases like interruptions, background noise, accents, ambiguous requests, failed integrations, and call transfers
- Implement authentication, privacy, logging, and data-handling requirements appropriate to the use case
- Monitor call outcomes, transcripts, latency, and failure patterns and refine agent behavior after deployment
How to hire an AI voice agent developer on Upwork
Upwork makes it straightforward to find, vet, and collaborate with the right developer. 89% of first-time clients complete a contract on Upwork, demonstrating that many new clients successfully move from hiring to project completion. Follow these four steps to move from job post to launch.
Step 1: Post a job
Start by describing your voice use case, technical environment, and the workflows the AI agent needs to support.
- Name your preferred voice AI platforms or frameworks, such as Vapi, Retell AI, LiveKit, or Voiceflow
- List required integrations, such as your CRM, calendar, APIs, databases, or telephony provider
- Describe your use case, such as inbound customer support, lead qualification, appointment scheduling, or outbound calls
- Define the actions the agent needs to perform, such as retrieving account information, scheduling appointments, or transferring calls
- Specify language, geographic, call-volume, latency, authentication, or privacy requirements when relevant
- State whether you need a prototype, an integration with an existing system, or a production-ready deployment
- Adapt this AI developer job description to your project
The Job Post Generator powered by Uma™, Upwork's Mindful AI, turns a few sentences about your needs into a ready-to-edit post. On Upwork, the average time from job post to first proposal is just three hours.
Step 2: Evaluate candidates
Review candidates for relevant voice AI experience and evidence that they can build reliable conversational workflows.
- Look for demos, recordings, or case studies of voice agents handling use cases similar to yours
- Confirm hands-on experience with relevant voice AI platforms, speech technologies, large language models (LLM), or orchestration tools
- Confirm experience integrating telephony providers and the CRM, calendar, APIs, or other systems your agent needs
Review candidates for relevant voice AI experience and evidence that they can build reliable conversational workflows.
- Look for demos, recordings, or case studies of voice agents handling use cases similar to yours
- Confirm experience with relevant voice AI platforms, speech technologies, LLMs, or orchestration tools
- Check experience integrating telephony providers and the CRM, calendar, APIs, or other systems your agent needs
- Look for evidence of handling interruptions, failed integrations, unexpected requests, and human handoffs
- Review how candidates test and monitor latency, task completion, transcription quality, and other relevant performance measures
- Check client feedback for technical ability, reliability, and communication
Uma can run instant video interviews and return shortlists with side-by-side candidate comparisons, so you can focus on the strongest fits.
Step 3: Interview your top choices
Use interviews to understand how candidates design reliable conversations, integrations, and escalation paths.
- Ask how they diagnose and reduce voice-agent latency without compromising reliability or response quality
- Explore how they design fallback behavior and human-handoff logic when the agent can’t complete a request
- Ask how they handle interruptions, background noise, ambiguous requests, and failed API calls
- Discuss how they protect sensitive customer data and authenticate callers when required
- Request a walkthrough of a voice agent they deployed and ask how they tested and improved it
- Ask which metrics they would use to evaluate your specific voice agent after launch
- Adapt these AI developer interview questions to guide the conversation
Schedule and hold interviews inside Upwork Messages. Uma will give you an automatic transcript and summary right after each conversation.
Step 4: Agree on scope and begin work
Define functionality, integrations, performance requirements, and acceptance criteria before development begins.
- Set milestones for stages such as conversation design, prototype development, integrations, testing, pilot deployment, and launch
- Define the call scenarios, business actions, integrations, languages, and escalation paths included in the scope
- Establish measurable acceptance criteria such as task completion, latency, transfer accuracy, and failure rates
- Confirm ownership and access requirements for source code, prompts, configurations, phone numbers, accounts, and other project assets
- Define testing requirements for expected workflows, edge cases, integrations, and human handoffs
- Agree on monitoring, reporting, incident handling, and postlaunch tuning responsibilities
Use messaging and the contract workroom to collaborate on the build, and lean on identity verification, payment protection, hourly tracking, and project funds to keep the engagement secure. Uma can also help you track milestones and next steps.
Upwork is not affiliated with and does not sponsor or endorse any of the tools or services discussed in this article. These tools and services are provided only as potential options, and each reader and company should take the time needed to adequately analyze and determine the tools or services that would best fit their specific needs and situation.
The rates and information provided in this article are based on current data and industry sources available at the time of publication. Freelance rates can vary depending on factors such as experience, location, project scope, and market conditions. Readers are encouraged to conduct their own research to confirm current rates and trends, as this information may change over time.