Code review should be fast

Agents are forcing a change in how we review code. Diffs brings code reviews directly inside Summar AI, so that the review lives alongside all of your product context.

Prerequisites

Before you start, you'll need a SummarAI account and an API key. If you don't have one, create a free account — no credit card required. Your API key is available from the Dashboard → Settings → API Keys.

Installation

Install the official SDK for your language. We provide first-party clients for Node.js, Python, and Go. All SDKs wrap the same underlying REST API — you can also call it directly.

Authentication

All API requests are authenticated using Bearer tokens. Pass your API key in the Authorization header of every request.

Request Parameters

The POST /v1/summaries endpoint accepts the following parameters in the request body as JSON.

Parameter	Type	Required	Description
`input`	`string`	`Required`	A URL (http/https), file path, or raw text string. Accepted types: PDF, DOCX, TXT, YouTube URL, Loom URL, MP3, M4A.
`format`	`string`	`Optional`	Output format. One of `paragraph`, `bullets`, `tldr`, `structured`, `action_items`. Defaults to `paragraph`.
`language`	`string`	`Optional`	BCP-47 language tag for the output. E.g. `en`, `fr`, `es`. Defaults to the detected input language.
`length`	`string`	`Optional`	Controls output verbosity. One of `short`, `medium`, `long`. Defaults to `medium`.
`features`	`string[]`	`Optional`	Array of additional features to run. Values: `sentiment`, `key_quotes`, `topics`, `data_extraction`. Pro plan required.
`webhook_url`	`string`	`Optional`	A URL to receive a `POST` callback when processing completes. Recommended for files over 50 pages or audio over 30 minutes.
`metadata`	`object`	`Optional`	Arbitrary key-value pairs attached to the summary object. Returned as-is on retrieval. Useful for your internal IDs or tags.

Async Processing

Large files and long audio recordings process asynchronously. When you submit a request, it returns immediately with status: "processing". Poll the summary's ID or use a webhook to know when it's done.

Supported Input Types

SummarAI automatically detects the content type from the URL or file extension. You can also force a specific type with the input_type parameter.

Type	Accepted Values	Max Size	Plan
`Document`	PDF, DOCX, TXT, HTML, MD	`500 pages`	Free (50p) · Pro+
`Video URL`	YouTube, Loom, Vimeo	`4 hours`	All plans
`Audio file`	MP3, M4A, WAV, FLAC	`500 MB`	Pro+
`Web article`	Any public HTTP/HTTPS URL	`—`	All plans
`Raw text`	Plain string in `input` field	`100,000 chars`	All plans

Error Handling

Errors return a non-200 status code with a JSON body containing a code, human-readable message, and optional details.

POST/v1/summaries422 Unprocessable

{
  "error": {
    "code":    "file_too_large",
    "message": "The uploaded file exceeds the 50-page limit for your plan.",
    "details": {
      "pages_detected": 127,
      "plan_limit":     50
    }
  }
}

{
  "error": {
    "code":    "file_too_large",
    "message": "The uploaded file exceeds the 50-page limit for your plan.",
    "details": {
      "pages_detected": 127,
      "plan_limit":     50
    }
  }
}

{
  "error": {
    "code":    "file_too_large",
    "message": "The uploaded file exceeds the 50-page limit for your plan.",
    "details": {
      "pages_detected": 127,
      "plan_limit":     50
    }
  }
}

Common error codes

Code	Status	Description
`invalid_api_key`	`401`	Key is missing, malformed, or revoked.
`insufficient_plan`	`403`	Feature requires a higher-tier plan.
`rate_limit_exceeded`	`429`	Too many requests. Retry after the `Retry-After` header value.
`file_too_large`	`422`	File exceeds the page or size limit for your plan.
`unsupported_format`	`422`	Input type or file format is not supported.
`processing_failed`	`500`	An internal error occurred. Retry once. Contact support if it persists.

Next Steps

Authenticate and make your first call

You've completed this step. Your API key is working and you can create summaries.

Explore output formats

Try format: "action_items" for meeting recordings or format: "structured" for research papers. Each format shapes the response differently.

Set up a webhook

For production workloads, use webhooks instead of polling. Pass a webhook_url and we'll push the completed result to your server.

Enable features

Add sentiment, key_quotes, or topics to the features array to enrich your summaries without making extra calls.