> ## Documentation Index > Fetch the complete documentation index at: https://docs.retellai.com/llms.txt > Use this file to discover all available pages before exploring further. # A/B Testing > Split traffic between multiple agents for inbound and outbound calls and chats to run experiments A/B testing lets you compare multiple agents or scripts by sending a percentage of traffic to each. You define a traffic split (for example, 80% to one agent and 20% to another) so you can test different prompts, voices, or flows without changing your main agent. ## Where A/B testing is available A/B testing is supported for: * **Inbound calls** — Calls received on a phone number * **Outbound calls** — Calls made from a phone number * **Inbound chats** — Incoming chat conversations * **Outbound chats** — Chat sessions you initiate ## How it works * **Multiple agents**: Bind or assign two or more agents to the same number or chat configuration. * **Traffic split**: Set the percentage of traffic each agent receives (e.g., 80% / 20%). Traffic is distributed according to this split. * **Use cases**: Test different scripts on marketing or support calls, try prompt or voice changes, or compare conversation flows in chat. ## Where to configure **Phone numbers (calls):** On the phone number configuration page, the A/B Testing toggle appears next to the Call Agent field. Turn it on to bind multiple agents and set a traffic split. The screenshot below shows the control with A/B testing disabled. Phone number configuration showing Call Agent dropdown and A/B Testing toggle in the off position After you turn the toggle on, you can add one or more agents and set the traffic percentage for each (for example, one agent at 100% or a split such as 80% / 20%). Call Agent section with A/B Testing on, showing one agent variant with 100% traffic and edit option Click **Edit** to open the A/B Testing modal. There you choose which agents to use and set a weight (percentage) for each. You can add multiple agents and remove or adjust them; the weights must total 100%. Click **Deploy** to save. A/B Testing modal with Agent and Weight columns, two agents at 50% each, Add button and Deploy/Cancel actions After you click **Deploy**, the configuration is active. The Call Agent section shows each agent and its traffic percentage (for example, a 50/50 split). You can click **Edit** anytime to change the agents or weights. Call Agent section with A/B Testing on, showing Agent A and Agent B each at 50% with Edit option | Context | Configure in | | ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Inbound calls** | Number configuration: bind multiple agents to the number and set the traffic split. See [Receive calls](/deploy/inbound-call). | | **Outbound calls** | Number configuration: bind multiple agents for outbound and set the traffic split. See [Outbound calls](/deploy/outbound-call). | | **Chat (inbound & outbound)** | Chat agent or widget configuration where you assign the chat agent; enable A/B testing and set the traffic split. See [Create Chat Completion](/deploy/create-chat-completion) and [Chat widget](/deploy/chat-widget). | ## View analytics by agent version After you deploy an A/B test, you can compare performance by specific agent versions in the Analytics dashboard. 1. Open **Analytics** in the Retell dashboard. 2. Set a date range that covers your experiment period. 3. In the filter bar, click **Agent** (or click **Filter** and add **Agent**). 4. In the left panel, select the agent(s) used in your A/B test. 5. In the right panel, select the specific version(s) you want to analyze (for example, `Version 3` vs `Version 4` of the same agent). 6. Click **Save** to apply the filter. All charts on the page will update to the selected agent-version scope, so you can compare metrics (such as call success rate, duration, and latency) for each variant. For more details on Analytics, see [Get analytics insight](/features/analytics-dashboard). ## A/B testing vs dynamic agent selection Use when you want a **random percentage-based split**. Traffic is distributed according to the percentages you set, with no per-call or per-chat logic. Use when you want to **choose the agent per call or per chat** based on caller, context, or other data. For inbound calls, use the [Inbound Call Webhook](/features/inbound-call-webhook). For outbound calls or chats, pass the agent (or other overrides) in the API when you create the call or chat.