Pre-Call Data Fetch & Dynamic VariablesCopy Anchor Link

A voice agent feels dramatically smarter when it already knows who is calling, what language they prefer, and why you are reaching out before speaking its opening line.

Talkar gives you three ways to inject dynamic data into initial_context prior to the Start Call node greeting:

1. Pre-Call HTTP Data Fetch (automatic HTTP request fired at call initialization — ideal for inbound calls and dynamic CRM lookups)
2. External Trigger API initial_context (for API-initiated outbound calls and embedded tests)
3. Campaign CSV columns (for bulk outbound campaigns)

Configuring Pre-Call Data Fetch (Start Call Node)Copy Anchor Link

On the Start Call node, enable Pre-Call Data Fetch (pre_call_fetch_enabled) and supply:

• Endpoint URL (pre_call_fetch_url): Any https:// endpoint (such as your n8n.talkar.in webhook or CRM middleware).
• Credential (pre_call_fetch_credential_uuid): Optional Credentials Vault entry. If using oauth2_client_credentials and the endpoint returns HTTP 401, Pre-Call Fetch automatically invalidates the cached token, refreshes it once, and retries.

What Talkar Sends to Your EndpointCopy Anchor Link

Talkar dispatches an HTTP POST request with a 10-second timeout immediately before the call begins:

{
  "event": "call_inbound",
  "call_inbound": {
    "agent_id": 42,
    "from_number": "+919876543210",
    "to_number": "+918061234567"
  }
}

Required JSON Response Format (initial_context / dynamic_variables)Copy Anchor Link

Talkar only merges keys wrapped under initial_context (canonical) or dynamic_variables (legacy fallback)—either at the top level or nested inside call_inbound. Flat top-level keys or "data": {...} wrappers are ignored!

{
  "initial_context": {
    "customer_name": "Rohan Sharma",
    "crm_lead_id": "LEAD-8492",
    "account_tier": "Enterprise",
    "open_ticket": "TKT-104"
  }
}

Inside your Start Call greeting and downstream Agent prompts, you can immediately reference any key returned inside initial_context:

Hi {{customer_name | fallback:there}}, thanks for calling support regarding ticket {{open_ticket | fallback:your account}}.

Always-Available System & Telephony ContextCopy Anchor Link

Every call automatically populates runtime telephony values before any prompt renders—even without Pre-Call Fetch:

Fallback & Error Handling BehaviorCopy Anchor Link

What happens if your Pre-Call Fetch endpoint times out (past 10s) or returns HTTP 4xx / 5xx?

• Talkar treats Pre-Call Fetch as fail-safe / non-fatal so callers are never dropped during temporary CRM outages.
• The returned keys simply remain absent from initial_context.
• Writing `{{var \| fallback:default}}` on every Pre-Call Fetch variable guarantees clean spoken phrasing even when a CRM lookup misses or returns null.

Good prompt pattern:

Address the caller as {{customer_name | fallback:there}}.
If {{open_ticket | fallback:none}} is not "none", ask if they are calling about ticket {{open_ticket | fallback:none}}.

Injecting Context on Outbound API & Campaign CallsCopy Anchor Link

For outbound calls, you rarely need Pre-Call Fetch because you already know the lead record when initiating the call:

• External Trigger API (POST /api/v1/public/agent/{uuid}): Pass all known CRM fields inside the request's initial_context object alongside phone_number.
• Campaigns CSV: Include any required variable referenced in your prompts (such as first_name, crm_id, renewal_date) as non-empty columns in your CSV upload alongside phone_number (+E.164). Each row populates initial_context for that lead's call.

See the Talkar Service API Reference and Nodes, Prompts & Variables for complete syntax rules.