Moving from Retell AI to Calldesk

A step-by-step checklist for teams moving a phone agent from Retell AI to Calldesk, based on Retell AI's public pages as of October 10, 2026.

Last verified October 10, 2026.

Details about Retell AI come from its public pages as they were on October 10, 2026. Retell AI may have changed them since, and a page that was unclear to us may be clear to you. Corrections: support@calldesk.tech. We make Calldesk, so read this page with that in mind and check anything important with Retell AI directly.

Moving from Retell AI: what kind of move this is

How Retell AI positions itself: A pay-as-you-go voice agent platform with a visual flow builder and API, bundling voice infrastructure in the per-minute rate while LLM, voice and telephony are priced as selectable line items.

Platforms like Retell AI are driven by code or API calls, so your agent probably exists as configuration you can read back plus tools and webhooks you wrote. Calldesk flows use their own steps, so expect to translate each prompt and tool into a step rather than import a file.

Retell AI's pages and our reading of them suggest it fits: teams that want a self-serve, usage-priced voice agent platform with a visual builder and a wide choice of models and voices, from startups through regulated enterprises.

Before you leave Retell AI

  • Exporting your agents: Retell AI documents a way to read your agents back out (the steps below list it).
  • Connected tools: list what you connected to Retell AI (Twilio, Telnyx, Vonage, Genesys Cloud, Five9, Avaya, Make, n8n, HubSpot, Go High Level, Google Drive, OneDrive and Notion knowledge-base sync and Custom LLM over WebSocket) so you can reconnect each one.
  • Recordings and transcripts: download anything you need to keep from Retell AI before you cancel.

Steps to leave Retell AI

These steps come from Retell AI's public pages. Sources are listed at the end.

  1. Retrieve agent settings with the List/Get Voice Agent API and the prompt/states with the Get Retell LLM or conversation flow endpoints. (source: docs.retellai.com)
  2. List knowledge bases with the List Knowledge Bases API and keep your original source documents or URLs. (source: docs.retellai.com)
  3. List phone numbers with the List Phone Numbers API; numbers imported through SIP trunking remain with your carrier and can be repointed. (source: docs.retellai.com)
  4. Call and chat history can be exported to CSV from the dashboard. (source: docs.retellai.com)
  5. Recreate the prompt, tools and knowledge base in the new platform and test before cutting over. (source: docs.retellai.com)

Your phone numbers

What Retell AI's pages say about numbers: Retell sells US and Canada numbers ($2 per month; US toll-free $5 per month); custom telephony via SIP trunking or SIP URI is supported with no Retell charge for the trunk.

Retell AI describes SIP trunks, and Calldesk does not offer SIP trunking. A number that reaches Retell AI through a trunk therefore cannot be pointed straight at Calldesk. Keep the number with its carrier and forward calls from there, or use one of the other routes below.

Limits Retell AI's pages state about numbers or moving out:

  • Retell-purchased phone numbers are limited to the US and Canada, and outbound calls from them are supported to 15 countries; other countries need custom telephony. (source: docs.retellai.com)
  • Forward: keep the number with its carrier, register it in the dashboard at no extra charge, and forward calls to it. This is the easiest route to undo.
  • Buy a new number from Telnyx or Twilio, a priced extra.
  • Port: a dashboard form sends a port-in request to Twilio. Treat it as a later step, not a promise that a number can move.

Steps on the Calldesk side

  1. Create an agent in Calldesk, in the dashboard, the API or the MCP server, and lay the conversation out as a flow.
  2. Add what the agent should know to a knowledge base, and connect a Cal.com account if it books appointments.
  3. Choose a plan; the costs section below lists them, and a language other than English needs the Standard or Pro voice.
  4. Connect your number by one of the routes above.
  5. Run test calls and simulation test cases, then promote the tested version from staging to production. The Live Calls page shows calls in progress, not audio.
  6. Rebuild your Retell AI connections with webhooks, the REST API or the MCP server (/docs).
  7. When calls look right, point your number at the Calldesk agent and keep Retell AI available for a short overlap period.

What Retell AI does well, to test before you switch

These are strengths Retell AI's own pages describe. Test the ones you rely on in Calldesk before you cancel.

  • True pay-as-you-go with no contract and 20 concurrent calls included, so small teams can start without a sales call. (source: retellai.com)
  • Wide choice of LLMs (OpenAI, Anthropic, Google, custom LLM over WebSocket) and voice providers with transparent per-minute rates listed publicly. (source: retellai.com)
  • Broad telephony options: Retell-purchased numbers or custom telephony via elastic SIP trunking, with guides for Twilio, Telnyx, Vonage, Genesys, Five9 and Avaya. (source: docs.retellai.com)
  • Built-in tooling beyond calls: simulation testing, AI quality assurance, batch calling, call transfer, SMS and verified/branded caller ID. (source: retellai.com)

What may not carry over

Plan on rebuilding the flow by hand: no automatic import from Retell AI is described here. Re-check voices, prompts and custom functions afterwards.

  • Not confirmed about Retell AI: exact HIPAA/BAA availability by plan is shown in a comparison table whose cell values we could not read; the compliance documentation says BAA/DPA self-signing has no additional fee.
  • Not confirmed about Retell AI: whether Retell-provided numbers can be ported out was not found.
  • Not confirmed about Retell AI: the Vanta trust center was not opened.
  • Not confirmed about Retell AI: the pricing page lists future-dated model names; per-model rates should be re-checked on the live page before quoting a specific model price.

Comparing costs before you move

Retell AI's own description of its pricing: Pay as you go, no subscription: a voice infrastructure rate plus the chosen LLM, voice and telephony per minute, with optional add-ons; custom enterprise pricing. Its published starting point: $0.07 to $0.31 per minute depending on the model and voice chosen; voice infrastructure is $0.055 per minute, and the vendor's example configuration totals $0.11 per minute.

Charges Retell AI's pages list outside that starting point, which are worth finding on your own invoice:

  • LLM: per-minute, depends on model (examples: GPT 4.1 mini $0.0128, GPT 5 $0.04, Claude Sonnet $0.064 to $0.08).
  • Text-to-speech: $0.015 per minute for Retell platform voices; ElevenLabs voices $0.04 to $0.10 per minute.
  • Telephony: about $0.015 per minute on Retell Twilio/Telnyx numbers; no charge for custom telephony/SIP trunking.
  • Optional add-ons: Knowledge Base +$0.005/min, Advanced Denoising +$0.005/min, Safety Guardrails +$0.005/min, PII Removal +$0.01/min, Batch Call +$0.005/dial, Branded Call +$0.10 per outbound call.
  • Phone number $2/month, verified phone number $10/month, SMS $0.01 per message.

Pricing limits Retell AI's pages state:

  • Per-minute cost varies widely ($0.07 to $0.31) with model and voice, and several features (knowledge base, denoising, guardrails, PII removal) are priced as per-minute add-ons. (source: retellai.com)

Plan terms Retell AI lists, which decide what you pay while you run both side by side:

  • Pay-as-you-go includes full platform access and 20 concurrent calls free; additional concurrency is $8 per concurrent call per month.
  • Enterprise: custom pricing, custom MSA/DPA, SSO, role-based access control, no cap on concurrent calls.
  • Example from the page: Retell platform voice $0.015, LLM about $0.04 (varies by model), voice infrastructure $0.055 = $0.11 per minute.
  • Phone numbers: $2 per month for US and Canada numbers purchased from Retell; US toll-free $5 per month (docs).
  • Testing is billed at production rates (docs).

On trial terms, Retell AI states: $10 in free credits on sign-up. Calldesk's free offer is a free demo call, with no trial credit.

On the Calldesk side: per minute of call time on three plans: Lite 2¢, Standard 5¢, Pro 9¢. No monthly minimum. Phone carrier charges are billed separately. Ask both for a month at your own volume with every charge included.

Sources