Reference Library
The spec sheets I keep open in a tab: image sizes, character limits, ad formats, and the technical values worth checking before a launch rather than after. Every page links the official source, because platforms change these without telling anyone.
Ad Platform Specs
10Google Ads Specs
Google Ads character limits for responsive search ads, Performance Max assets, image sizes and video requirements.
Meta Ads Specs
Facebook and Instagram ad specs: image and video ratios, text limits, placement requirements and file constraints.
LinkedIn Ads Specs
LinkedIn ad formats and specs: single image, video, carousel, document and message ads with character limits.
TikTok Ads Specs
TikTok ad specs for In-Feed ads and Spark Ads: video dimensions, length, text limits and safe zone guidance.
Display Ad Sizes
Standard IAB display banner sizes, the highest inventory formats, and file size limits for HTML5 and static display ads.
Google Performance Max Specs
Asset group requirements for Google Performance Max: image counts and ratios, headline and description limits, video rules and logo specs.
YouTube Ads Specs
YouTube ad formats, skippable and non skippable length rules, bumper limits, companion asset sizes and the text fields for each format.
Amazon Ads Specs
Amazon Sponsored Products, Sponsored Brands and Sponsored Display specs: headline limits, logo and image requirements and campaign structure notes.
Reddit Ads Specs
Reddit ad formats, image and video sizes, headline limits, and targeting notes for teams buying against subreddits and interests.
Native Ad Specs
Common native advertising specs across Taboola, Outbrain and similar networks: image sizes, headline limits and disclosure requirements.
Email Specs
7Email Design Specs
Email template width, image sizes, font and file constraints, plus dark mode and accessibility guidance for HTML email.
Email Subject Line Length
How many characters of an email subject line and preheader are visible across Gmail, Outlook, Apple Mail and mobile inboxes.
Email Deliverability Checklist
Authentication, list hygiene and content checks that keep marketing email out of spam, including Gmail and Yahoo bulk sender rules.
Email Image Specs
Image widths, file formats, retina handling, alt text rules and file size guidance for HTML email that renders reliably across clients.
Email Client Support Reference
What HTML and CSS features the major email clients support, where Outlook breaks, and which techniques are safe to use in production.
Spam Trigger Words Reference
Words and patterns associated with spam filtering, why single words rarely cause filtering, and the signals that genuinely affect inbox placement.
Email Sending Frequency Reference
Sending frequency benchmarks by programme type, warm up guidance for new domains, and how to decide cadence from engagement data.
SEO Reference
7Meta Tag Length Guide
Title tag and meta description length limits, pixel widths, Open Graph tags, and what Google actually displays in results.
Schema Types for Marketers
The structured data types that matter for marketing sites, which ones earn rich results, and required properties for each.
HTTP Status Codes for SEO
What each HTTP status code means for crawling and indexing, when to use 301 versus 302, and how Google treats soft 404s.
Robots.txt Directives Reference
Robots.txt directives Google actually supports, correct syntax and wildcards, common mistakes, and how robots.txt differs from noindex.
Google Search Operators
Google search operators that still work, what each one does, and how to combine them for technical SEO audits and competitive research.
Core Web Vitals Thresholds
Core Web Vitals metrics and their good, needs improvement and poor thresholds, plus how field data is assessed and what moves each metric.
Canonical Tag Rules
How rel canonical works, correct implementation patterns, common mistakes, and when to use a canonical instead of a redirect or noindex.
Analytics Reference
4UTM Parameter Reference
The five UTM parameters, what each one is for, naming conventions that survive scale, and common tagging mistakes.
GA4 Metrics Glossary
Plain language definitions of GA4 metrics and dimensions, including engaged sessions, engagement rate and key events.
Conversion Tracking Reference
Conversion tracking methods across GA4, Google Ads and Meta, including client side, server side and enhanced conversions, and when to use each.
Attribution Models Reference
Attribution models compared: last click, first click, linear, time decay, position based and data driven, with guidance on when each is appropriate.
Social Media Specs
12Social Media Image Sizes
Current image dimensions and aspect ratios for Instagram, Facebook, LinkedIn, X, TikTok, YouTube and Pinterest, in one scannable table.
Social Media Character Limits
Character limits for posts, bios, captions and headlines across Instagram, LinkedIn, X, TikTok, Facebook and YouTube.
Instagram Specs
Instagram image sizes, Reels and Stories video specs, caption and bio limits, and file requirements in one reference.
LinkedIn Specs
LinkedIn image dimensions, video specs, character limits for posts, headlines and articles, plus document post requirements.
TikTok Specs
TikTok video dimensions, aspect ratio, length limits, caption and bio character counts, and safe zone guidance for creators.
YouTube Specs
YouTube video resolutions, thumbnail and banner sizes, title and description limits, and Shorts requirements in one table.
X (Twitter) Specs
X post character limits, image and video dimensions, header and profile sizes, and card requirements for marketers.
Facebook Specs
Facebook image and video sizes, Page asset dimensions, post and bio character limits, and link preview requirements in one reference.
Pinterest Specs
Pinterest Pin sizes, Idea Pin and video specs, title and description limits, and Rich Pin requirements for ecommerce and content teams.
Threads Specs
Threads post limits, image and video specs, link behaviour and profile fields, with notes on how Threads differs from Instagram and X.
Social Video Aspect Ratios
Which video aspect ratios each social platform supports, which crop cleanly across placements, and how to shoot once for multiple outputs.
Hashtag Limits by Platform
Maximum hashtags allowed per platform, the number actually worth using, and where hashtags still affect distribution in practice.