Retell AI
AIPut Retell AI voice agents to work inside FlowRunner. Agents place phone and web calls, fetch transcripts and recordings, and manage Retell agents, LLM configurations, voices, and phone numbers end to end.
What This Integration Enables
The phone is the highest-stakes channel in your stack. A bad email gets ignored. A bad call is your brand's voice in a customer's ear, in real time, and every minute of it is billed. Retell AI puts capable voice agents on that channel, and this connector puts them under orchestration: FlowRunner agents place phone and web calls with per-lead dynamic variables, collect transcripts, sentiment, and success outcomes when calls end, archive recordings to FlowRunner file storage, and manage the Retell agents, LLM configurations, voices, and phone numbers behind it all. This is the clearest case in the catalog for the FlowRunner thesis. The Retell API itself warns that Create Phone Call places a real, billable outbound call. A capability like that should not run as an unattended loop, and here it does not have to: [human-in-the-loop](/concepts/human-in-the-loop/) approval is a native step, so voice automation ships with a person holding the dial button by default, not as an afterthought bolted on later.
Without FlowRunner
With FlowRunner
Use Case Scenarios
Qualification calls driven by the CRM
Overnight, the CRM marks a batch of leads call-ready. The agent pulls each lead's phone number and context from [HubSpot](/integrations/hubspot), verifies the script version with Get Agent, and screens the list against List Calls so nobody gets called twice in a week. The batch posts for approval, and once the ops lead clears it, Create Phone Call dials each lead with their details injected as dynamic variables. As calls end, Get Call returns the transcript, sentiment, and outcome, and qualified leads route straight to reps with the conversation attached.
Post-call intelligence and the compliance archive
On a schedule, the agent runs List Calls for the day, writes each call's duration, outcome, and sentiment to [Google Sheets](/integrations/google-sheets) for the volume and cost dashboard, and posts flagged calls to the sales channel in [Slack](/integrations/slack): negative sentiment on top, each with its summary. Download Call Recording archives the audio of completed calls to FlowRunner file storage, so the compliance trail exists whether or not anyone asks for it this quarter. Calls where the customer asked for a human get routed to a rep for a personal callback.
Appointment reminders that reschedule themselves
When tomorrow's bookings come up, the agent places reminder calls through Create Phone Call with the appointment details as dynamic variables. The voice agent confirms, and when a customer wants to reschedule, the outcome comes back through Get Call and the flow rebooks the slot in [Calendly](/integrations/calendly). For web visitors, Create Web Call issues the access token that opens a browser-based voice session with the same agent. No-show rates stop being a problem someone manages by hand.
Human-in-Loop Highlight
Create Phone Call is the most consequential action on this page, and Retell's own API says so: it places a real outbound telephone call and incurs real, billable charges, per minute, across voice, LLM, and telephony. An agent that dials a list is spending money and your reputation with every ring. So no campaign in FlowRunner starts itself. The agent assembles the batch, verifies the script binding with Get Agent, and asks the ops lead in Slack: "Ready to dial 212 leads with script v14 on the Dallas number. List and talking points attached. Approve the batch or hold?" Nothing dials until the approval lands. The same gate covers the other standing commitments: Create Phone Number adds a recurring monthly charge, and Delete Agent permanently destroys an agent and every version of it, dropping calls on any number still routing to it. Money spent and voices retired are human decisions. The agent just makes them easy to take.
Agent Capabilities
20 actionsCalls
5- Create Phone Call Places a real outbound telephone call with per-lead dynamic variables, incurring billable per-minute charges. Always run behind batch approval.
- Create Web Call Registers a browser-based voice call and returns the access token the Retell Web SDK uses to open the session. Used for on-site voice assistants.
- Get Call Retrieves a call's full record: status, transcript, sentiment, and outcome. The step that turns a finished call into CRM data.
- List Calls Retrieves call history with filters by agent, status, direction, sentiment, and time window. Used for dedup screens and reporting sweeps.
- Download Call Recording Fetches a completed call's audio into FlowRunner file storage and returns a URL. Used to build the compliance archive.
Voice Agents
5- List Agents Lists every voice agent with its published configuration. Used to audit what can pick up the phone.
- Get Agent Retrieves a single agent's full configuration including voice, language, and response engine binding. The pre-dial verification step.
- Create Agent Creates a voice agent by pairing a response engine with a voice and speech configuration. Used to stand up new call programs.
- Update Agent Applies a partial update, swapping the voice, retargeting the engine, or tuning speech settings. Used for staged, reviewed iteration.
- Delete Agent Permanently deletes an agent and all its versions; numbers bound to it stop routing. Cannot be undone; always behind human sign-off.
Retell LLMs
5- List Retell LLMs Lists every conversational engine in the account. Used to audit prompts in production.
- Get Retell LLM Retrieves an engine's full definition: general prompt, begin message, model, and tools. Used to review before changes.
- Create Retell LLM Creates the conversational engine behind an agent, defining persona, goals, and guardrails. Used when launching a new call program.
- Update Retell LLM Partially updates an engine to iterate on the prompt or swap the model. Used with review, since it changes what the voice says live.
- Delete Retell LLM Permanently deletes an engine and its versions; agents still bound to it stop working. Kept behind approval.
Voices
2- List Voices Lists every available text-to-speech voice, built-in and cloned. Used to select the program's voice.
- Get Voice Retrieves a voice's details with a preview audio URL for auditioning. Used before assigning a voice to an agent.
Phone Numbers
3- List Phone Numbers Lists every number in the account with its inbound and outbound agent bindings. Used to audit routing.
- Create Phone Number Purchases a real number and adds a recurring monthly charge. A spend decision, so it waits for human approval.
- Get Phone Number Retrieves a number's configuration including which agents handle its calls. Used to verify routing before a campaign.
Frequently Asked Questions
What can FlowRunner do with Retell AI?
FlowRunner agents can run Create Phone Call, Create Web Call, and Get Call in Retell AI, plus 17 more actions.
Does connecting Retell AI to FlowRunner require OAuth?
No. Retell AI connects to FlowRunner with an API key, no OAuth flow required.
Can Retell AI trigger a FlowRunner workflow automatically?
Retell AI doesn't currently expose triggers in FlowRunner. It connects as an action step inside workflows started by another trigger.
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