--- title: "Lead Reply API - Auto-Respond Docs" description: "A lightweight API for posting replies back into Auto-Respond from an external system, authenticated with a per-source secret key." source: https://auto-respond.com/docs/integrations/lead-reply-api/ last_updated: 2026-04-21 --- ![Lead Reply API documentation guide](https://auto-respond.com/assets/docs/integrations-lead-reply-api.svg "Lead Reply API Documentation") A visual guide to the Lead Reply API documentation, covering the setup, configuration, and workflow details explained on this page. Documentation illustration for Lead Reply API. # Lead Reply API The Lead Reply API lets an external system **send replies back into Auto-Respond** so they’re delivered to the lead as if your team sent them from inside the app. This is the pair of the [REST Webhook](https://auto-respond.com/docs/integrations/rest-webhook/) integration: the webhook sends lead data **out**, the Lead Reply API posts replies **back in**. Together they let a developer-owned workflow fully own the conversation. ℹ️ The Lead Reply API card is on any source’s **Messaging Settings** → **Integrations** tab. Use it alongside the REST Webhook if you want a full outbound-plus-inbound integration. ## What you’ll get - A **Secret key** for this source that your external system uses to authenticate when sending replies. - The ability to post outbound messages back to the lead from your own software. - Inbound activity from the lead still shows up in Auto-Respond (and in your webhook receiver if you have one wired up). ## Connecting the Lead Reply API ### Open the integration In Auto-Respond, open the source → **Messaging Settings** → **Integrations** tab → **Lead Reply API** card. ### Copy the Secret key Auto-Respond generates a **Secret key** when the card is set up. Copy it and store it as a credential in your external system. Your system will include this key on every call it makes to the Lead Reply API so Auto-Respond can confirm the call really came from you. You can **Regenerate** the secret at any time. Regenerating invalidates the old key immediately - update your caller before regenerating in production. ### Validate and save Click **Validate Connection** to confirm the secret is active. ### Turn on the Enable toggle The API won’t accept replies for this source until **Enable** is on. ## Options ### Enable Turns the integration on or off for this source. Default: **off**. When off, calls to the Lead Reply API for this source are rejected. ### Inherit from parent Only shown on a location with a parent business. When **on**, the location uses the parent’s secret key. When **off**, it has its own. ### Secret key The credential your external system uses to authenticate. Keep it secret and rotate it (via **Regenerate**) if it’s ever exposed. The old key stops working the moment a new one is generated. ### Validate Connection Confirms the current secret is active. ### Disconnect Clears the secret and turns the integration off. Confirmation required. ## Typical setup Most customers use the Lead Reply API together with the [REST Webhook](https://auto-respond.com/docs/integrations/rest-webhook/): 1. Wire up the REST Webhook so your system gets notified of new leads and messages. 2. Enable the Lead Reply API on the same source and copy its secret. 3. In your system, when you want to reply to a lead, call the Lead Reply API with the secret and the reply text. The reply is delivered to the lead. If you’re taking over the conversation entirely, turn on **Skip welcome and follow-ups** on the REST Webhook card so Auto-Respond’s automated messages don’t interfere with yours. ## Disconnecting Open the Lead Reply API card → click **Disconnect** → confirm. The secret is cleared. Any external system still calling with the old secret will get rejected. ## Troubleshooting - **Calls being rejected** - Confirm **Enable** is on and that your caller is sending the current secret. If you regenerated it, old callers need to be updated. - **Replies aren’t reaching the lead** - Make sure you’re identifying the correct lead in your call, and that the lead’s conversation is still open on the source. - **I want the reverse direction too** - Enable the [REST Webhook](https://auto-respond.com/docs/integrations/rest-webhook/) on the same source so your system also gets notified of inbound activity. *** Questions about the Lead Reply API? Email . Last updated: April 21, 2026