Sync vs async execution

Workflows can run synchronously (the caller waits for completion) or asynchronously (the caller gets an execution_id immediately and the workflow runs in the background).

At a glance

	Sync	Async
Caller behavior	Waits for completion	Returns immediately with `execution_id`
Wait steps	Served inline, up to 5s each and 15s per run; longer fails	Suspend the execution, any duration
Max duration	~60s practical limit	Up to the workflow’s configured timeout (default 1 hour)
Retries	Not supported	Configurable per workflow
Used by	Agent tools, Ongoing Conversation	Timer, External Apps, Post Call, batch jobs

When to use sync

The caller needs the result immediately (agent tool during a live call)
Total expected duration is well under 30 seconds
No Wait steps
Low-latency response matters

When to use async

The workflow has Wait steps longer than a few seconds
The workflow has a Loop step over more than a handful of items — iterations run one after another, so the time adds up
The workflow has a Parallel step over more than 10 items — that is the sync ceiling; async allows 200
Total duration could exceed 30 seconds
Retry on failure matters
The caller doesn’t need the result synchronously
High-concurrency batch processing

Sync execution

curl -X POST https://api.anyreach.ai/workflow/workflow-executions \
  -H "Authorization: Bearer $ANYREACH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "workflow_id": "wf_...",
    "workflow_version": "latest",
    "input_data": { "customer_email": "alice@example.com" }
  }'

Success response:

{
  "status": "success",
  "execution_id": "exec_...",
  "output": { /* whatever the Output step returned */ }
}

Failure response:

{
  "status": "failed",
  "execution_id": "exec_...",
  "error": { "step_name": "Lookup contact", "message": "..." }
}

Async execution

curl -X POST https://api.anyreach.ai/workflow/workflow-executions/async \
  -H "Authorization: Bearer $ANYREACH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "workflow_id": "wf_...",
    "workflow_version": "latest",
    "input_data": { "customer_email": "alice@example.com" }
  }'

Immediate response:

{
  "status": "pending",
  "execution_id": "exec_..."
}

Poll for the result:

curl https://api.anyreach.ai/workflow/workflow-executions/$EXEC_ID \
  -H "Authorization: Bearer $ANYREACH_TOKEN"

Getting Started

Agents

Knowledge Bases

Telephony

Web Widgets

Email

Campaigns

Conversations

Evaluation & Metrics

Agent Assist

Workflows

Custom Data

Anyreach in Claude

Organizations & Billing

Sync vs async execution

At a glance

When to use sync

When to use async

Sync execution

Async execution

​At a glance

​When to use sync

​When to use async

​Sync execution

​Async execution

At a glance

When to use sync

When to use async

Sync execution

Async execution