Zapier API - The Complete Developer Guide to Building Integrations, Embedding Workflows, and Connecting AI Agents

Zapier Developer Platform (Build a Zapier integration)

The Developer Platform is how you create a Zapier “app” (integration) so that users can include your product in a Zap. Zapier’s docs note that all new integrations are built using Zapier Platform v3, and you can build them using either the Platform UI (visual builder) or the Platform CLI (local JavaScript development). (See docs: “How Zapier works”.)

Powered by Zapier Workflow API (Embed Zapier inside your product)

“Powered by Zapier” is Zapier’s embed solution. The Workflow API is described as a way to build “native feeling” workflow experiences for your end users and access Zapier’s integration directory within your product’s UI. This is the path if you want users to create and manage workflows without leaving your product.

Zapier MCP (Model Context Protocol)

Zapier MCP is a standardized way to connect AI assistants to Zapier’s actions. Zapier describes MCP as a way to connect AI assistants to thousands of apps, enabling the AI to take actions like creating tasks, updating records, and sending messages through natural language commands. Zapier MCP is currently in beta and is part of your existing Zapier plan.

Supporting “API-like” ways users automate

In addition to the official developer surfaces, Zapier users often interact with APIs using:

• Webhooks by Zapier (send/receive HTTP requests in Zaps).
• Custom API Request actions (build API calls inside Zap steps).
• Instant triggers via REST Hooks (Zapier subscribes to your server and your app pushes events to Zapier).

These aren’t “Zapier’s API” as a developer product, but they’re essential to understand because your integration might rely on webhooks or need to support instant triggers.

Platform UI (visual builder)

The Platform UI is a web-based visual builder. Zapier describes it as a visual way for builders who are comfortable with APIs but prefer a form editor to writing everything in code. It supports advanced calls and response parsing via “Code mode,” but it’s primarily designed as a visual configuration workflow.

Platform CLI (local JavaScript)

The Platform CLI is a command line workflow for building, testing, and pushing Zapier integrations from your local environment. Zapier’s docs describe it as your gateway to creating custom applications with a code-first approach (installable via npm). It supports version control, team collaboration, and CI-friendly deployment patterns.

Triggers

Every Zap begins with a trigger. Zapier describes triggers as how users start automated workflows when an item is added or updated in your app: new contacts, records, tasks, form entries, etc.

Actions

Actions are the steps a Zap performs after the trigger fires. Actions commonly create or update data: create a CRM lead, post a message, add a spreadsheet row, update a database record, generate a document, etc.

Searches

Searches are a special class of action that “finds” something rather than creating it. Zapier’s platform includes a dedicated “Search action” type so users can locate an existing record before deciding what to do next (e.g., “Find contact, then update it; otherwise create it”).

Polling vs instant triggers

Triggers usually come in two flavors:

• Polling triggers: Zapier calls your endpoint on an interval and checks for new items.
• Instant triggers (REST Hook triggers): Zapier subscribes to your server and your app pushes events to a Zap-specific URL.

Zapier’s docs for REST Hook triggers explain that Zapier uses a unique URL per activated Zap; your server sends a payload to that URL to trigger the Zap immediately.

Input fields and output fields

Integrations live or die on UX details:

• Input fields define what a user can configure in a Zap step (e.g., “Project,” “Assignee,” “Message”).
• Output fields define what data becomes available to later steps (e.g., record ID, timestamps, URLs).

A good practice is to model fields to match your API semantics, keep labels user-friendly, and include help text that explains where the user finds required values (especially API keys).

OAuth v2 (preferred)

Zapier’s platform docs state that OAuth v2 is the preferred scheme when possible because it simplifies account connection and matches modern integration expectations. Users authenticate via your app’s site (authorization flow), and Zapier stores the token for subsequent API calls.

// (Illustrative) OAuth v2 token exchange pattern in Zapier-style pseudo-code
// 1) User authorizes on your site (Zapier opens a popup)
// 2) Your app redirects back to Zapier with a code
// 3) Zapier exchanges code for token via your token endpoint
// 4) Zapier stores the token and includes it on future requests

API Key Auth (next best)

Zapier supports API key authentication as a common option after OAuth. Zapier’s docs recommend that if you use API keys, users should be able to obtain their key in your product without human intervention (no support tickets required). Your Zapier auth form should include clear help text so users can find the key quickly.

// Example of API key auth usage conceptually:
// Authorization: Bearer <API_KEY>
// or header: X-API-Key: <API_KEY>
// Zapier can store the key and include it in requests for the user’s Zaps.

Basic Auth

Zapier supports Basic Authentication for legacy or simple services. It’s usually a last resort because it requires the user to provide credentials directly (username/password), which many modern products avoid.

If you must use Basic Auth, consider offering app-specific passwords or “API passwords” to reduce risk.

Session Auth

Zapier also supports Session Authentication, described as combining elements of Basic Auth and OAuth-like flows: Zapier exchanges user credentials for a token (similar to a browser session cookie), then uses that token for subsequent calls.

Session Auth is useful when your API uses a “login endpoint → session token” pattern and OAuth isn’t available.

Build and test locally (CLI path)

The CLI tutorial walks through building an example app, testing, and pushing it to Zapier. The core idea is you define triggers/actions/searches in code, run tests (including manual “zap runs” in the editor), and then push versions.

# Typical CLI-style workflow (illustrative)
npm install -g zapier-platform-cli
zapier login
zapier init my-app
zapier test
zapier push

Treat every push as a versioned release. Use Git tags + release notes so your team can trace behavior changes.

Build in the Platform UI (visual path)

The Platform UI tutorial focuses on building an integration with authentication, a trigger, and an action using a browser-based builder. This can be a fast route to an MVP integration when your logic maps cleanly to HTTP requests.

What is the Workflow API?

Zapier’s “Powered by Zapier” docs describe the Workflow API as a tool for building workflow experiences for your end users, letting them discover and manage workflows directly within your product. The “Getting Started” page describes it as access to the industry’s largest integration directory (thousands of apps), enabling users to craft and manage workflows in your UI.

What you can build with Powered by Zapier

The embed toolkit is broader than endpoints. It typically includes:

• Workflow creation UI that matches your product’s look and feel
• Managed authentication flows so users can connect apps safely
• Zap discovery and templates relevant to your product
• Zap management (list, filter, inspect steps, enable/disable)

Zapier’s embed overview also notes that your integration must be published as a public integration in Zapier’s App Directory to use the embed solution.

Listing a user’s zaps (v2)

Zapier’s “retrieving a list of zaps” guidance mentions leveraging the /zaps endpoint, filtering by input values, using the expand parameter to include more detail (like step info), and using scopes such as zap:all to return all owned Zaps on a user’s account (depending on paired apps).

// (Illustrative) Fetch Zaps
GET https://api.zapier.com/v2/zaps
Authorization: Bearer <User Access Token>

# Optional: expand details
GET /v2/zaps?expand[]=steps

Authentications (managed auth objects)

The Workflow API includes authentication endpoints used to create and retrieve “Authentications” for a given app. The docs note that listing authentications returns those owned by the user (since you can’t create Zaps with authentications you don’t own).

// (Illustrative) List Authentications for an app
GET https://api.zapier.com/v2/authentications?app_id=123
Authorization: Bearer <User Access Token>

# Create an Authentication (server-side)
POST https://api.zapier.com/v2/authentications
Authorization: Bearer <User Access Token>
Content-Type: application/json

What Zapier MCP is

Zapier describes MCP as a standardized way to connect AI assistants to thousands of apps and services, enabling an AI to take real actions (send messages, create tasks, update records) through natural language commands. Zapier MCP is currently in beta and part of your existing Zapier plan.

Quickstart concept (how MCP works)

MCP integrations typically involve:

1. Configure a Zapier MCP server in Zapier’s dashboard
2. Connect it to an MCP client (an AI assistant / agent platform)
3. The client calls tools; Zapier executes actions and returns results

Zapier’s MCP quickstart describes getting up and running in minutes and notes it works similarly across MCP clients (Claude is a common example).

Webhooks by Zapier (user-facing API calls)

Many Zapier users rely on Webhooks steps when an app doesn’t have a dedicated action, or when they need a custom endpoint. This is important for you as a developer because:

• Your API should support clean JSON responses (and meaningful errors).
• You should document header auth patterns clearly (Bearer token, API key headers, etc.).
• You should provide stable IDs in response payloads so users can map outputs.

Instant triggers via REST Hooks

Zapier supports instant triggers using REST Hook subscriptions. Zapier’s docs describe that Zapier subscribes to your server with a unique URL per Zap, and your app posts event payloads to that URL when the trigger event occurs.

This model is often more real-time than polling and can reduce API load—if your webhook infrastructure is reliable and secure.

// (Illustrative) Your server pushes a trigger event:
POST https://hooks.zapier.com/hooks/catch/...unique-per-zap...
Content-Type: application/json

{
  "id": "evt_123",
  "type": "contact.created",
  "created_at": "2026-02-08T10:11:12Z",
  "contact": { "id": "c_999", "email": "user@example.com" }
}

Reliability checklist

• Idempotency: create actions should be safe to retry; use idempotency keys if your API supports them.
• Stable primary keys: keep a stable id field for dedup and record linking.
• Pagination: ensure triggers/searches support pagination (limit/offset/cursor).
• Rate limits: handle 429s gracefully; Zapier may retry; your API should return clear headers when possible.
• Timeouts: keep endpoints fast; avoid long-running synchronous operations; consider async job endpoints.

Security checklist

• Use OAuth v2 when possible and scope tokens minimally.
• Rotate secrets (client secrets, API keys) and support revocation.
• Webhook verification: sign webhook payloads or include shared secrets to prevent spoofing.
• Least privilege: do not over-request OAuth scopes “just in case.”
• Auditability: log action runs server-side with request IDs and user IDs (privacy-aware).