---
headline: Version Control | Opik Documentation
og:description: Create, fetch, and compare Prompt Library versions using the Opik UI
and SDK
og:site_name: Opik Documentation
og:title: Prompt Library Version Control
title: Version control
---
Every change to a prompt in the Prompt Library creates a new immutable version, numbered
sequentially as `v1`, `v2`, `v3`, … Once created, a version can't be modified — you always have
a full audit trail.
You can create new versions from the Opik UI or from code using the SDK.
## Creating a new version
To create a new version from the Opik platform:
1. Navigate to the **Prompt Library** for your project
2. Open the prompt you want to edit
3. Click **Edit** and update the template
4. Click **Create new version**
The new version is available immediately.
Call `create_prompt` (or `create_chat_prompt`) again with the same `name` and the updated
template — the SDK creates the next sequential version automatically:
```python
import opik
client = opik.Opik()
# v1
client.create_prompt(
name="system_prompt",
prompt="You are a helpful assistant.",
project_name="my-agent",
)
# v2
client.create_prompt(
name="system_prompt",
prompt="You are a coding assistant specializing in {{language}}.",
project_name="my-agent",
)
```
If the template is identical to the latest version, no new version is created.
Call `createPrompt` (or `createChatPrompt`) again with the same `name` and the updated
template — the SDK creates the next sequential version automatically:
```ts
import { Opik } from "opik";
const client = new Opik();
// v1
await client.createPrompt({
name: "system_prompt",
prompt: "You are a helpful assistant.",
projectName: "my-agent",
});
// v2
await client.createPrompt({
name: "system_prompt",
prompt: "You are a coding assistant specializing in {{language}}.",
projectName: "my-agent",
});
```
If the template is identical to the latest version, no new version is created.
## Fetching a specific version
Pass the `version` parameter to fetch a specific version, or omit it to fetch the most recent:
```python title="Python"
import opik
client = opik.Opik()
# Fetch a specific version
v3 = client.get_prompt(name="system_prompt", version="v3", project_name="my-agent")
# Fetch the most recent version (omit `version`)
latest = client.get_prompt(name="system_prompt", project_name="my-agent")
```
```ts title="TypeScript"
import { Opik } from "opik";
const client = new Opik();
// Fetch a specific version
const v3 = await client.getPrompt({
name: "system_prompt",
version: "v3",
projectName: "my-agent",
});
// Fetch the most recent version (omit `version`)
const latest = await client.getPrompt({
name: "system_prompt",
projectName: "my-agent",
});
```
## Comparing versions
You can compare any two versions side-by-side in the Opik UI to see exactly what changed. This is
useful for reviewing changes before pointing your agent at a new version.
