SnapAPI · Controlled Vocabulary

SnapAPI Vocabulary

Normative vocabulary for SnapAPI, a headless-Chromium-powered REST API for website screenshots, metadata extraction, text extraction, and PDF generation. Covers the SnapAPI request surface, rendering options, usage signaling, and pricing tiers.

15 Terms Updated 2026-05-27
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SnapAPI Vocabulary is a controlled vocabulary published by SnapAPI on the APIs.io network, defining 15 terms.

Defined terms include API Key, Tier, Screenshot, Full Page, and Viewport.

A controlled vocabulary pins the words an API’s schemas, parameters and documentation use to one agreed definition each — the shared language a human or an agent needs to read the API the same way its authors do.

Terms

API Key
A `snap_`-prefixed secret string issued by POST /api/signup. Passed on every authenticated request via the `X-API-Key` header. Identifies the developer and binds usage to a tier and monthly quota.
Tier
A pricing plan that determines monthly request volume. SnapAPI offers four tiers: Free (50 req/mo, $0), Starter (500 req/mo, $5/mo — $2.50/mo launch special), Basic (2,000 req/mo, $15/mo), and Pro (10,000 req/mo, $39/mo).
Screenshot
A PNG or JPEG image of a rendered web page returned by POST /api/screenshot. Supports custom viewport dimensions (320-3840 wide, 240-2160 tall) and an optional full-page mode that captures the entire scrollable canvas.
Full Page
A screenshot rendering mode (`full_page: true`) that captures the entire scrollable page rather than only the viewport. Useful for long-form content captures.
Viewport
The simulated browser window dimensions used by headless Chromium when rendering a page. Controlled by the `width` and `height` request parameters.
Metadata
The structured page-level data extracted by POST /api/metadata: title, description, favicon, Open Graph tags, Twitter Card tags, and the full raw meta-tag list.
Open Graph
Meta tags conforming to the Open Graph protocol (ogp.me). SnapAPI surfaces these as the `og` object in metadata responses, keyed without the `og:` prefix.
Twitter Card
Meta tags used by Twitter/X to render rich link previews. SnapAPI surfaces these as the `twitter` object in metadata responses, keyed without the `twitter:` prefix.
Text Extraction
The visible text content of a web page returned by POST /api/text, with HTML markup stripped and a word count attached. Suitable for content analysis, NLP pipelines, and reading-time estimation.
PDF Generation
Conversion of a URL to a PDF document by POST /api/pdf. Supports A4, Letter, Legal, and Tabloid page formats and an optional landscape flag.
Paper Format
The page format used when rendering a PDF. One of A4 (default), Letter, Legal, or Tabloid.
Usage
The current calendar-month request count for an API key. Returned in the `usage` object of JSON responses and via the `X-Usage-Used` and `X-Usage-Limit` response headers on the screenshot endpoint. Also queryable directly via GET /api/usage.
Quota
The monthly request ceiling for a tier (50, 500, 2000, or 10000). Quotas reset at the start of each calendar month. Exceeding the quota returns HTTP 429.
Headless Chromium
The rendering engine that backs every SnapAPI endpoint. Each screenshot, metadata, text, or PDF request spins up a headless Chrome page to fetch and render the target URL.
Signup
Self-service issuance of an API key via POST /api/signup. Requires only an email address and an application name; no credit card. The returned key is shown once and must be stored by the caller.

Controlled Vocabulary

Raw ↑ 
name: SnapAPI Vocabulary
description: >-
  Normative vocabulary for SnapAPI, a headless-Chromium-powered REST API for
  website screenshots, metadata extraction, text extraction, and PDF generation.
  Covers the SnapAPI request surface, rendering options, usage signaling, and
  pricing tiers.
version: "1.0"
created: "2026-05-27"
modified: "2026-05-27"
terms:
  - term: API Key
    definition: >-
      A `snap_`-prefixed secret string issued by POST /api/signup. Passed on every
      authenticated request via the `X-API-Key` header. Identifies the developer
      and binds usage to a tier and monthly quota.
    tags:
      - Authentication
      - Identity

  - term: Tier
    definition: >-
      A pricing plan that determines monthly request volume. SnapAPI offers four
      tiers: Free (50 req/mo, $0), Starter (500 req/mo, $5/mo — $2.50/mo launch
      special), Basic (2,000 req/mo, $15/mo), and Pro (10,000 req/mo, $39/mo).
    tags:
      - Pricing
      - Quota

  - term: Screenshot
    definition: >-
      A PNG or JPEG image of a rendered web page returned by POST /api/screenshot.
      Supports custom viewport dimensions (320-3840 wide, 240-2160 tall) and an
      optional full-page mode that captures the entire scrollable canvas.
    tags:
      - Core
      - Rendering

  - term: Full Page
    definition: >-
      A screenshot rendering mode (`full_page: true`) that captures the entire
      scrollable page rather than only the viewport. Useful for long-form
      content captures.
    tags:
      - Rendering
      - Screenshot

  - term: Viewport
    definition: >-
      The simulated browser window dimensions used by headless Chromium when
      rendering a page. Controlled by the `width` and `height` request parameters.
    tags:
      - Rendering

  - term: Metadata
    definition: >-
      The structured page-level data extracted by POST /api/metadata: title,
      description, favicon, Open Graph tags, Twitter Card tags, and the full
      raw meta-tag list.
    tags:
      - Core
      - Extraction
      - SEO

  - term: Open Graph
    definition: >-
      Meta tags conforming to the Open Graph protocol (ogp.me). SnapAPI surfaces
      these as the `og` object in metadata responses, keyed without the `og:`
      prefix.
    tags:
      - Metadata
      - Social

  - term: Twitter Card
    definition: >-
      Meta tags used by Twitter/X to render rich link previews. SnapAPI surfaces
      these as the `twitter` object in metadata responses, keyed without the
      `twitter:` prefix.
    tags:
      - Metadata
      - Social

  - term: Text Extraction
    definition: >-
      The visible text content of a web page returned by POST /api/text, with
      HTML markup stripped and a word count attached. Suitable for content
      analysis, NLP pipelines, and reading-time estimation.
    tags:
      - Core
      - Extraction
      - NLP

  - term: PDF Generation
    definition: >-
      Conversion of a URL to a PDF document by POST /api/pdf. Supports A4,
      Letter, Legal, and Tabloid page formats and an optional landscape flag.
    tags:
      - Core
      - Rendering
      - PDF

  - term: Paper Format
    definition: >-
      The page format used when rendering a PDF. One of A4 (default), Letter,
      Legal, or Tabloid.
    tags:
      - PDF
      - Rendering

  - term: Usage
    definition: >-
      The current calendar-month request count for an API key. Returned in the
      `usage` object of JSON responses and via the `X-Usage-Used` and
      `X-Usage-Limit` response headers on the screenshot endpoint. Also queryable
      directly via GET /api/usage.
    tags:
      - Observability
      - Quota

  - term: Quota
    definition: >-
      The monthly request ceiling for a tier (50, 500, 2000, or 10000). Quotas
      reset at the start of each calendar month. Exceeding the quota returns
      HTTP 429.
    tags:
      - Pricing
      - Quota

  - term: Headless Chromium
    definition: >-
      The rendering engine that backs every SnapAPI endpoint. Each screenshot,
      metadata, text, or PDF request spins up a headless Chrome page to fetch
      and render the target URL.
    tags:
      - Rendering
      - Infrastructure

  - term: Signup
    definition: >-
      Self-service issuance of an API key via POST /api/signup. Requires only an
      email address and an application name; no credit card. The returned key
      is shown once and must be stored by the caller.
    tags:
      - Authentication
      - Onboarding