REST APIs in Networking Explained
A REST API lets you configure and query network devices over HTTP instead of the CLI — sending structured requests and receiving JSON back. It's how controllers (Cisco DNA Center) and modern platforms are programmed at scale, and the foundation of network automation beyond simple SSH scripting.
The HTTP methods map to actions
| Method | Action |
|---|---|
| GET | Retrieve data (read config/status) |
| POST | Create a new resource |
| PUT/PATCH | Update an existing resource |
| DELETE | Remove a resource |
You send a request to an endpoint URL (with authentication), optionally with a JSON body, and get a JSON response plus a status code (200 OK, 401 Unauthorized, etc.).
REST vs NETCONF/RESTCONF
Controllers and cloud platforms typically expose REST APIs. Network devices themselves increasingly offer RESTCONF (REST-style access to YANG data models) and NETCONF (XML-based, transaction-safe). All three replace screen-scraping the CLI with structured, reliable programmatic access — the shift SDN is built on.
Why it matters
CLI scripting parses human-readable text that can change format between versions — fragile. APIs return structured data with a defined schema — robust. This reliability is why automation-focused roles and the CCNP blueprint emphasise API-driven management. Pair with Python (the requests library) to call them.
Frequently asked questions
What is a REST API in networking?
A programmable HTTP interface for configuring and querying devices or controllers — sending structured requests and receiving JSON responses instead of using the CLI.
What do GET, POST, PUT and DELETE do?
GET retrieves data, POST creates a resource, PUT/PATCH updates one, and DELETE removes it — the standard REST operations mapping to read/create/update/delete.
What is the difference between REST, RESTCONF and NETCONF?
REST is the general HTTP API style (common on controllers); RESTCONF exposes YANG data models REST-style; NETCONF is an XML-based, transaction-safe protocol for device configuration.
Why are APIs better than CLI scripting?
APIs return structured data with a defined schema, so automation is reliable — unlike parsing human-readable CLI output, which can change format and break scripts.
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