frappe-core-api

name	frappe-core-api
description	Use when building ERPNext/Frappe API integrations (v14/v15/v16) including REST API, RPC API, authentication, webhooks, and rate limiting. Covers external API calls, endpoint design, token/OAuth2/session authentication. Keywords: API integration, REST endpoint, webhook, token authentication,, how to connect, external API, send data to another system, API not working, 401 error. OAuth, frappe.call, external connection, rate limiting.
license	MIT
compatibility	Claude Code, Claude.ai Projects, Claude API. Frappe v14-v16.
metadata	{"author":"OpenAEC-Foundation","version":"2.0"}

Frappe API Patterns

Deterministic patterns for REST, RPC, and webhook integrations with Frappe.

---

Decision Tree

What do you need?
├── CRUD on documents (external client)
│   ├── v14: REST /api/resource/{doctype}
│   └── v15+: REST /api/v2/document/{doctype} (new) or /api/resource/ (still works)
│
├── Call custom server logic (external client)
│   └── RPC: POST /api/method/{dotted.path.to.function}
│
├── Notify external systems on document events
│   └── Webhooks (configured in UI or via DocType)
│
├── Client-side calls (JavaScript in Frappe desk)
│   ├── frappe.xcall() — async/await (RECOMMENDED)
│   └── frappe.call() — callback/promise pattern
│
└── Authentication method?
    ├── Server-to-server integration → Token Auth (RECOMMENDED)
    ├── Third-party app / mobile → OAuth 2.0
    ├── Browser session (short-lived) → Session/Cookie Auth
    └── Quick scripting / testing → Token Auth

---

Authentication Methods

Token Auth (RECOMMENDED for integrations)

headers = {
    'Authorization': 'token api_key:api_secret',
    'Accept': 'application/json',
    'Content-Type': 'application/json'
}

Generate keys: User > Settings > API Access > Generate Keys. ALWAYS store API secret immediately — it is shown only once.

Basic Auth (alternative token format)

import base64
credentials = base64.b64encode(b'api_key:api_secret').decode()
headers = {'Authorization': f'Basic {credentials}'}

OAuth 2.0 (third-party apps)

# Step 1: Authorization redirect
GET /api/method/frappe.integrations.oauth2.authorize
    ?client_id={id}&response_type=code&scope=openid all
    &redirect_uri={uri}&state={random}

# Step 2: Exchange code for token
POST /api/method/frappe.integrations.oauth2.get_token
    grant_type=authorization_code&code={code}
    &redirect_uri={uri}&client_id={id}

# Step 3: Use bearer token
Authorization: Bearer {access_token}

# Refresh token
POST /api/method/frappe.integrations.oauth2.get_token
    grant_type=refresh_token&refresh_token={token}&client_id={id}

Session/Cookie Auth

session = requests.Session()
session.post(url + '/api/method/login', json={'usr': 'email', 'pwd': 'pass'})
# Subsequent requests use session cookie automatically

Session cookies expire after ~3 days. NEVER use for long-running integrations.

---

REST API: Resource CRUD

Endpoints

Operation	Method	v14 Endpoint	v15+ v2 Endpoint
List	GET	/api/resource/{doctype}	/api/v2/document/{doctype}
Create	POST	/api/resource/{doctype}	/api/v2/document/{doctype}
Read	GET	/api/resource/{doctype}/{name}	/api/v2/document/{doctype}/{name}
Update	PUT	/api/resource/{doctype}/{name}	PATCH /api/v2/document/{doctype}/{name}
Delete	DELETE	/api/resource/{doctype}/{name}	DELETE /api/v2/document/{doctype}/{name}
Copy	—	—	GET /api/v2/document/{doctype}/{name}/copy [v15+]
Doc Method	—	—	POST /api/v2/document/{doctype}/{name}/method/{method} [v15+]

ALWAYS include Accept: application/json header — without it, Frappe MAY return HTML.

List Parameters

Parameter	Type	Description	Default
fields	JSON array	Fields to return	["name"]
filters	JSON array	AND conditions	none
or_filters	JSON array	OR conditions	none
order_by	string	Sort expression	modified desc
limit_start	int	Pagination offset	0
limit_page_length	int	Page size	20
limit	int	Alias for limit_page_length [v15+]	—
debug	bool	Show SQL in response	false

Filter Operators

filters = [["status", "=", "Open"]]
filters = [["amount", ">", 1000]]
filters = [["status", "in", ["Open", "Pending"]]]
filters = [["date", "between", ["2024-01-01", "2024-12-31"]]]
filters = [["reference", "is", "set"]]       # NOT NULL
filters = [["reference", "is", "not set"]]   # IS NULL
filters = [["name", "like", "%INV%"]]
filters = [["status", "not in", ["Cancelled"]]]

Full operator list: =, !=, >, <, >=, <=, like, not like, in, not in, is, between.

Pagination Pattern

import json, requests

def get_all_records(doctype, headers, base_url, page_size=100):
    all_data, offset = [], 0
    while True:
        params = {
            'fields': json.dumps(["name", "modified"]),
            'limit_start': offset,
            'limit_page_length': page_size
        }
        resp = requests.get(f'{base_url}/api/resource/{doctype}',
                            params=params, headers=headers)
        data = resp.json().get('data', [])
        if not data:
            break
        all_data.extend(data)
        if len(data) < page_size:
            break
        offset += page_size
    return all_data

Create with Child Table

requests.post(f'{base_url}/api/resource/Sales Order', json={
    "customer": "CUST-001",
    "items": [
        {"item_code": "ITEM-001", "qty": 5, "rate": 100},
        {"item_code": "ITEM-002", "qty": 2, "rate": 250}
    ]
}, headers=headers)

Update (Partial)

# Only specified fields are changed
requests.put(f'{base_url}/api/resource/Customer/CUST-001',
             json={"customer_group": "Premium"}, headers=headers)

File Upload

requests.post(f'{base_url}/api/method/upload_file',
    files={'file': ('doc.pdf', open('doc.pdf', 'rb'), 'application/pdf')},
    data={'doctype': 'Customer', 'docname': 'CUST-001', 'is_private': 1},
    headers={'Authorization': 'token api_key:api_secret'})
# NOTE: Do NOT set Content-Type header — requests sets multipart boundary automatically

---

RPC API: Custom Methods

Server-Side Endpoint

@frappe.whitelist()
def get_balance(customer):
    """GET /api/method/myapp.api.get_balance?customer=CUST-001"""
    return frappe.db.get_value("Customer", customer, "outstanding_amount")

@frappe.whitelist(methods=["POST"])
def create_payment(customer, amount):
    """POST /api/method/myapp.api.create_payment"""
    if not frappe.has_permission("Payment Entry", "create"):
        frappe.throw(_("Not permitted"), frappe.PermissionError)
    pe = frappe.new_doc("Payment Entry")
    pe.party_type = "Customer"
    pe.party = customer
    pe.paid_amount = float(amount)
    pe.insert()
    return pe.name

@frappe.whitelist(allow_guest=True)
def public_status():
    """No authentication required."""
    return {"status": "ok"}

Decorator Options

Option	Effect	Version
allow_guest=True	No authentication needed	All
methods=["POST"]	Restrict HTTP methods	[v14+]
xss_safe=True	Skip XSS escaping on response	All

Response Structure

// RPC success
{"message": "return_value"}

// REST success
{"data": {...}}

// Error
{"exc_type": "ValidationError", "_server_messages": "[{\"message\": \"...\"}]"}

Client-Side Calls (JavaScript)

// RECOMMENDED: async/await with frappe.xcall
const result = await frappe.xcall('myapp.api.get_balance', {
    customer: 'CUST-001'
});

// Alternative: frappe.call with promise
frappe.call({
    method: 'myapp.api.get_balance',
    args: {customer: 'CUST-001'},
    freeze: true,
    freeze_message: __('Loading...')
}).then(r => console.log(r.message));

// Document method (frm.call)
frm.call('get_linked_doc', {throw_if_missing: true})
    .then(r => console.log(r.message));

Standard frappe.client Methods

Method	Endpoint	Purpose
frappe.client.get_value	POST	Get single field value
frappe.client.get_list	POST	List with filters
frappe.client.get	POST	Get full document
frappe.client.insert	POST	Create document
frappe.client.save	POST	Update document
frappe.client.delete	POST	Delete document
frappe.client.submit	POST	Submit document
frappe.client.cancel	POST	Cancel document
frappe.client.get_count	POST	Count documents

---

Webhooks

Configure via Webhook DocType in the UI. Events:

Event	Trigger
after_insert	New document created
on_update	Every save
on_submit	After submit (docstatus=1)
on_cancel	After cancel (docstatus=2)
on_trash	Before delete
on_update_after_submit	After amendment
on_change	On every change

Security: ALWAYS set a Webhook Secret. Frappe adds X-Frappe-Webhook-Signature header with base64-encoded HMAC-SHA256 of payload. Verify on receiving end.

Conditions: Use Jinja2 — {{ doc.grand_total > 10000 }}.

See references/webhooks-reference.md for complete handler examples.

---

HTTP Status Codes

Code	Meaning	Common Cause
200	Success	—
400	Bad request	Validation error
401	Unauthorized	Missing or invalid auth
403	Forbidden	No permission for operation
404	Not found	Document does not exist
417	Expectation failed	Server exception (frappe.throw)
429	Rate limited	Too many requests
500	Server error	Unhandled exception

---

Critical Rules

1. ALWAYS include Accept: application/json header in API requests
2. ALWAYS add permission checks in @frappe.whitelist() methods
3. ALWAYS validate and sanitize input in whitelisted methods
4. ALWAYS use parameterized queries — NEVER string-interpolate SQL
5. ALWAYS use timeout=30 on external requests calls
6. ALWAYS store credentials in frappe.conf or env vars — NEVER hardcode
7. ALWAYS verify webhook signatures with HMAC-SHA256
8. ALWAYS paginate list responses — NEVER return unbounded result sets
9. NEVER use allow_guest=True on state-changing endpoints
10. NEVER log credentials or sensitive data
11. NEVER use Administrator API keys for integrations — create dedicated API users

---

Anti-Patterns

Do NOT	Do Instead
No permission check in whitelist	frappe.has_permission() before action
frappe.db.sql(f"...{user_input}")	Parameterized %s queries
allow_guest=True + state change	Require authentication
Return all records without limit	Paginate with limit_page_length
Hardcode API credentials	frappe.conf.get("api_key")
Synchronous heavy processing	frappe.enqueue() for long tasks
No timeout on external calls	requests.get(url, timeout=30)
Inconsistent response format	ALWAYS return {"status": "...", "data": ...}

---

Version Differences

Feature	v14	v15	v16
/api/resource/ (v1)	Yes	Yes	Yes
/api/v2/document/ (v2)	No	Yes	Yes
/api/v2/doctype/{dt}/meta	No	Yes	Yes
/api/v2/doctype/{dt}/count	No	Yes	Yes
limit alias parameter	No	Yes	Yes
PKCE for OAuth2	Limited	Yes	Yes
Server Script rate limiting	No	Yes	Yes
Doc method via v2 URL	No	Yes	Yes

---

Reference Files

File	Contents
authentication-methods.md	Token, Session, OAuth2 with code examples
rest-api-reference.md	Complete REST CRUD with filters and pagination
rpc-api-reference.md	Whitelisted methods, frappe.call, frappe.xcall
webhooks-reference.md	Webhook config, security, handler examples
anti-patterns.md	Common mistakes with fixes
examples.md	Python/JS/cURL client implementations

Related Skills

• frappe-core-permissions — Permission system for API endpoints
• frappe-core-database — Database queries behind API methods
• frappe-syntax-hooks — Hook configuration for webhooks
• frappe-syntax-controllers — Controller methods called via API

---

Verified against Frappe docs 2026-03-20 | Frappe v14/v15/v16