OG Image API Reference

The OG image API reference covers every endpoint, parameter, and template for generating dynamic Open Graph images with FastOG. The API is credit-based — you pay per render — and HMAC-signed URLs keep each request secure. Sign up free for 100 credits, then create your API key and HMAC secret in the dashboard; renders carry a FastOG watermark until your first payment. Copy an example, hit the endpoint, and ship.

Base URL

https://fastog.com/api/v1/og

Authentication

All requests require HMAC-SHA256 signature authentication. See the HMAC Documentation for details.

Endpoint

GET `/api/v1/og`

Generates a dynamic Open Graph image based on the provided parameters.

Query Parameters

Parameter	Type	Required	Description
`template`	string	No	Template name (default: `default`)
`title`	string	No	Main title text
`subtitle`	string	No	Subtitle or description text
`key`	string	Yes	Full API key
`s`	string	Yes	HMAC-SHA256 signature (64 hex chars)
`t`	number	Yes	Unix timestamp in seconds

Template-Specific Parameters

Every template accepts the shared parameters below plus its template-specific parameters (see the index table). The template query parameter selects which layout is used (default: default).

Shared parameters (all templates)

Parameter	Type	Description
`title`	string	Main heading text
`subtitle`	string	Supporting text
`tags`	list	Comma-separated tag labels
`theme`	string	`dark` \| `light` \| `glass`
`gradient_preset`	string	Named gradient preset (e.g. `indigo`, `ocean`, `sunset`, `cosmic`)
`gradient_direction`	number	Gradient angle in degrees (default `135`)
`bg_color`	hex	Solid background color
`pattern`	string	Background pattern (`grid`, `dots`, `noise`, `none`, …)
`pattern_color`	hex	Pattern color
`pattern_intensity`	number	Pattern opacity (1–30)
`font_family`	string	`font-sans`, `font-jakarta`, `font-dm`, `font-outfit`, `font-space`, `font-playfair`, `font-merriweather`, `font-instrument`, `font-jetbrains`, `font-fira`
`accent_color`	hex	Accent color for highlights
`auto_text_color`	bool	Derive text color from the background (default `true`)
`title_color`	hex	Override title color
`subtitle_color`	hex	Override subtitle color
`brand_name`	string	Brand/logo text (default `FastOG`)
`brand_logo`	string	Brand logo image URL
`layout_mode`	string	`split` \| `centered` \| `banner` (template-specific variants apply)

Template index — 41 templates:

`template`	Template	Category	Additional parameters
`default`	Default	Brand	—
`blog`	Blog Post	Content	`author`, `date`, `domain`
`ecommerce`	E-commerce	Commerce	`price`, `original_price`, `rating`, `rating_total`, `features`, `badge`, `image`, `domain`
`company`	Company	Brand	`domain`, `logo`, `tag`
`launch`	Product Launch	Brand	`kicker`, `version`, `tag`, `cta`, `domain`
`saaslaunch`	SaaS Launch	Brand	`kicker`, `cta`, `domain`
`devtool`	Developer Tool	Developer	`version`, `badge`, `domain`
`game`	Game	Content	`price`, `rating`, `image`, `domain`
`event`	Event	Social	`location`, `host`, `date`, `domain`
`quote`	Quote	Social	`quote`, `author_name`, `author_title`
`job`	Job Posting	Social	`location`, `department`, `salary`, `job_type`, `domain`
`stats`	Stats	Data	`metric`, `metric_label`, `delta`
`pricing`	Pricing	Commerce	`price`, `period`, `cta`
`podcast`	Podcast	Media	`episode_number`, `guest_name`, `guest_role`, `duration`
`video`	Video	Media	`duration`, `channel`, `views`
`editorial`	Editorial	Content	`kicker`, `author`, `date`, `domain`
`minimal`	Minimal	Brand	`domain`
`changelog`	Changelog	Developer	`version`, `tag`
`corporate`	Corporate	Brand	`kicker`, `tag`, `domain`
`hero`	Hero	Brand	`kicker`, `cta`, `status`, `domain`
`imageright`	Image Right	Commerce	`kicker`, `image`, `domain`
`logos`	Logo Wall	Brand	`kicker`, `brand_logos`, `domain`
`notice`	Notice	Social	`notice_status`, `notice_icon`, `notice_text`, `date`, `domain`
`testimonial`	Testimonial	Social	`quote`, `author_name`, `author_title`, `company`, `author_avatar`, `rating`, `rating_total`, `quote_style`
`logofocus`	Logo Focus	Content	`kicker`, `domain`
`xheader`	X Header	Social	`size`, `handle`, `followers`, `location`, `website`, `avatar`
`bento`	Bento	Data	`kicker`, `tiles`, `domain`
`comparison`	Comparison	Commerce	`kicker`, `left_label`, `left_desc`, `left_points`, `right_label`, `right_desc`, `right_points`, `verdict`
`timeline`	Timeline	Content	`kicker`, `milestones`, `domain`
`countdown`	Countdown	Brand	`kicker`, `target_date`, `cta`, `domain`
`news`	News	Content	`headline`, `byline`, `author`, `date`, `source`, `image`
`code`	Code	Developer	`code`, `language`, `terminal_title`, `author`, `domain`
`testimonialpro`	Testimonial Pro	Social	`quote`, `author_name`, `author_title`, `company`, `author_avatar`, `rating`, `rating_total`, `cta`
`product`	Product	Commerce	`badge`, `title`, `price`, `original_price`, `rating`, `rating_total`, `features`, `image`, `layout_mode`
`promo`	Promo	Brand	`brand_name`, `benefits`, `title`, `subtitle`, `domain`, `layout_mode`
`devblog`	Dev Blog	Content	`category`, `title`, `subtitle`, `tags`, `author`, `author_title`, `date`, `read_time`, `views`, `likes`, `comments`, `code`, `language`, `file_path`
`codepost`	Code Post	Content	`category`, `date`, `title`, `subtitle`, `author`, `read_time`, `code`, `file_path`, `language`
`statsbar`	Stats Bar	Data	`kicker`, `metric`, `metric_label`, `delta`, `stats`, `domain`
`changelogpro`	Changelog Pro	Developer	`version`, `tag`, `title`, `changes`, `features`, `domain`
`quotecta`	Quote CTA	Social	`quote`, `author_name`, `author_title`, `company`, `cta`, `domain`
`appscreenshot`	App Screenshot	Media	`badge`, `title`, `subtitle`, `app_name`, `rating`, `screenshot`, `domain`

Structured parameter types

Type	Format	Example
`list`	Comma-separated values	`features=Fast,Cheap,Secure`
`tiles`	Line-separated `label\|value` pairs	`tiles=Requests\|12.4M\nUptime\|99.99%`
`milestones`	Line-separated `date\|title\|description`	`milestones=Q3 2026\|Alpha\|Invite-only`
`changes`	Line-separated `type\|text` (`added`,`fixed`,`improved`,`removed`)	`changes=added\|Bento templates`

Response

200 OK — Returns PNG image data
401 Unauthorized — Invalid or missing authentication
422 Unprocessable — Invalid template parameters

Error Responses

Error Code	HTTP Status	Description
`missing_signature`	401	Missing `s`, `t`, or `key` parameter
`invalid_signature_format`	401	Signature not 64 hex characters
`expired_timestamp`	401	Timestamp older than 5 minutes
`invalid_signature`	401	Signature verification failed
`missing_api_key`	401	Missing API key

Example Request

GET /api/v1/og?template=blog&title=Hello%20World&subtitle=A%20test%20post&key=sk_quick_123abc&s=a1b2c3...&t=1722718800

Example cURL

bash

curl "https://fastog.com/api/v1/og?template=blog&title=Hello%20World&key=sk_quick_123abc&s=<signature>&t=<timestamp>"

Pricing & Limits

FastOG is credit-based: each image render costs 1 credit. There is no separate

requests-per-minute cap on the API — your credit balance is the limit.

Pack	Price	Credits	Per image
Starter	$2.00	1,200	~$0.0017
Pro (Popular)	$9.00	6,300	~$0.0014
Business	$40.00	32,000	~$0.0013

Per-image cost is price ÷ credits.

Cached images are free: requests served from the Cloudflare edge cache (same template +

params, regardless of the t/s signature) never reach the origin, so they cost 0 credits —

only the first render of a given image is charged.

Watermark: until your first completed payment, every rendered image carries a small FastOG

badge (the 100 free signup credits are a trial). After your first credit top-up the watermark is

removed from all future renders. The API sets an X-FastOG-Watermark response header

(1 = watermarked, 0 = clean) so you can detect it programmatically.

Documentation — All FastOG guides and references
Free OG Image Tester— Preview without an account
Quick Start Guide — includes the architecture flow (sign at render time)
HMAC Signature Guide
HMAC Validation
JavaScript Tutorial

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