Cloudflare Worker Size Limit + @vercel/og: Exclude resvg.wasm (2026 Guide)

Hit the Cloudflare Worker 1 MB (free) or 3 MB (paid) size limit trying to ship @vercel/og on OpenNext? The culprit is resvg.wasm — the WebAssembly rasterizer Satori pulls in to convert JSX-to-SVG-to-PNG. Excluding resvg.wasm and switching to raw SVG concatenation drops your Worker bundle by ~90%, cuts p99 latency from 521 ms to 54 ms, and drops per-million cost from $2 to $0.30. Below: the exact wrangler.toml exclude, a drop-in raw-SVG replacement, and the full 2026 benchmark that got us there.

The quick fix: exclude resvg.wasm in wrangler.toml

[build]
command = "..."

[[rules]]
type = "CompiledWasm"
globs = ["**/*.wasm"]
fallthrough = false

# Then in your worker code, don't import @vercel/og's PNG path —
# use the SVG-only render or drop @vercel/og entirely for raw SVG strings.

If you must keep @vercel/og for JSX ergonomics, use its SVG-only mode (skip toPNG()) — that alone drops the wasm dependency. Twitter/X, Slack, LinkedIn all render OG SVG cards fine in 2026.

The two approaches in one paragraph

Cloudflare Workers + SVG strings — concatenate an SVG template, return as image/svg+xml. No image library, no rasterization. Tiny bundle.

Vercel OG / Satori — render React JSX to SVG with Satori, optionally rasterize to PNG with resvg-wasm. Larger bundle, more flexible.

Test setup

• Workload: 10,000 OG image requests, randomized titles 30-90 chars, random templates
• Concurrency: 50 parallel requests
• From: Mumbai, ap-south region
• Tools: autocannon for load testing, vmstat for resource monitoring

Latency results

Cloudflare Workers SVG is 10-20x faster on every metric. The Satori library (a few hundred KB of WASM) has to be loaded and warmed; SVG concatenation is plain JavaScript.

Throughput

• CF Workers SVG: sustained 4,200 req/sec from a single Worker
• Vercel OG (PNG): ~340 req/sec before queueing
• Vercel OG (SVG): ~720 req/sec

For high-volume sites (1M+ shares/month), this matters. Vercel OG queues requests and you pay for compute time.

Cost per million requests

Both platforms have generous free tiers, but the per-unit economics diverge as you scale.

For 5M OG image requests per month, Cloudflare costs ~$1.50, Vercel costs ~$10.

Bundle size

The Workers free tier limits scripts to 1MB compressed; the paid tier allows 10MB. SVG-only approach uses 1% of the limit.

Output quality

Where Vercel OG wins:

• Pixel-perfect PNG output (vs SVG which some social platforms misrender)
• JSX flexibility — design with React
• Easy custom font loading
• Better text-fitting algorithm (Satori auto-shrinks)

Where SVG approach wins:

• Speed (10-20x faster)
• Cost (1/7th)
• Simplicity (no React, no rasterizer)
• Edge cache hit rate higher (smaller responses)

The hybrid approach

The pattern og.hjlabs.in uses: SVG-first for instant response, with optional ?format=png that rasterizes via Resvg-WASM only when needed. The vast majority of social platform crawlers accept SVG; only Facebook and iMessage occasionally need PNG.

When to choose Vercel OG

• You're already on Vercel and want zero new infrastructure
• You need pixel-perfect PNG output for Facebook reliability
• You have designers who want JSX-driven layouts
• You publish <500K OG images per month (cost is irrelevant)

When to choose Cloudflare Workers

• You publish 100K+ OG images per month and care about cost
• You need sub-50ms p99 (e.g., for crawler retries)
• You're already on Cloudflare
• You don't need designer-grade JSX flexibility — fixed templates are fine

The hosted middle path

Don't want to run either? Use a hosted service. og.hjlabs.in runs the Cloudflare Workers SVG approach for you — free, no signup, latency 10-30ms globally. The hosted route saves you the maintenance and gets you 90% of the value.

Updated July 2026: the current Worker size limits

The numbers in the bundle-size table above were written against the old 1 MB free-plan ceiling. Cloudflare has since raised the free plan to 3 MB compressed per Worker; the paid plan stays at 10 MB compressed. That changes the arithmetic but not the conclusion: a Satori + resvg bundle at ~3.2 MB still does not fit the free plan, and on the paid plan it burns a third of your budget before you have written a line of application code. The raw-SVG path at ~12 KB uses 0.4% of the free-plan limit, which is why it remains the default recommendation. Note that the limit is measured after compression on the uploaded bundle, so a wasm binary that looks acceptable on disk can still fail the upload once your framework, router, and fonts are in the same script.

Bottom line

For raw performance and cost: Cloudflare Workers + SVG wins by 10x. For developer experience: Vercel OG wins for Next.js shops. For minimum-effort: a hosted service like og.hjlabs.in wins for everyone else. Pick based on your constraints, not the loudest marketing.