COMPARISON · PDFRELAY VS SELECTPDF · 2026-07-14
SelectPdf alternative: PDFRelay vs SelectPdf (2026)
SelectPdf has long converted HTML and URLs to PDF, with deep roots in the .NET ecosystem: a self-hosted .NET library (millions of NuGet downloads) sold under perpetual per-developer licenses, plus a cloud REST API for teams that don't want to run .NET themselves. The REST API is language-agnostic, but the product's documentation and heritage are .NET-first.
PDFRelay is API-first from the ground up, with no library-vs-API decision to make. It renders with Chromium by default — SelectPdf's REST API defaults to its older WebKit engine and requires explicitly selecting Blink or Chromium to get browser-current output. Metering also differs: SelectPdf's REST API charges by page count (50 pages per credit), while PDFRelay counts a document as one unit no matter how many pages it has, and identical re-renders are served from cache for free.
Feature by feature
| Feature | PDFRelay | SelectPdf |
|---|---|---|
| Default rendering engine | Chromium (browser-faithful, on by default) | WebKit (Chromium/Blink available, opt-in) |
| Metering | Flat per document | Page-count credits (50 pages = 1 credit) |
| Cached repeats | Free, never counted | Counted per conversion |
| Deployment model | API only | Self-hosted .NET library or cloud REST API |
| HTML + URL modes | Yes (SSRF-guarded) | Yes |
| Free tier | 150 docs/mo, no card, ongoing | 7-day trial, 200 conversions, no card |
| Quota transparency | X-Pdfrelay-Quota-* headers on every response | Dashboard |
Pricing
| Tier | PDFRelay | SelectPdf |
|---|---|---|
| Free | Free — 150 docs/mo, no card | 7-day trial — 200 conversions |
| Entry | $12/mo — 1,500 docs | $19/mo — 2,000 conversions (Entry) |
| Mid | $29/mo — 5,000 docs | $29/mo — 5,000 conversions (Standard) |
| Upper | $79/mo — 20,000 docs | $59/mo — 20,000 conversions (Advanced) |
| High volume | Contact us | $119–$449/mo — 50k to unlimited (Premium, Ultra, Dedicated) |
Where SelectPdf shines — and where it hurts
STRENGTHS · SELECTPDF
- Long track record with a large .NET install base and millions of NuGet library downloads
- Self-hosted .NET library option under a perpetual license — documents never leave your infrastructure, no per-conversion metering
- Multiple selectable rendering engines and high-volume ceilings (100,000/mo Ultra, unlimited Dedicated)
TRADE-OFFS · SELECTPDF
- REST API defaults to the older WebKit engine — Chrome-exact output requires explicitly selecting Chromium
- Page-count credit metering (50 pages/credit) is less predictable than flat per-document pricing
- Only a 7-day free trial, not an ongoing free tier
- Documentation and positioning are .NET-centric, which can slow adoption for other stacks
Frequently asked
Should I use SelectPdf's .NET library or its REST API?
The self-hosted .NET library is the stronger SelectPdf option if you're already on .NET and want documents to stay on your infrastructure under a perpetual license. If you're not on .NET, or want to avoid running the rendering engine yourself, SelectPdf's REST API and PDFRelay both work as HTTP-only alternatives — PDFRelay defaults to Chromium without needing an engine selection.
How does PDFRelay's pricing compare to SelectPdf's?
PDFRelay counts documents, not pages: a document is one unit regardless of length, within the request cap, and cached repeats are free. SelectPdf's REST API meters 50 pages per credit, so multi-page documents consume more of your quota. At entry tiers, PDFRelay is $12/month for 1,500 documents versus SelectPdf's $19/month for 2,000 conversions, and PDFRelay's free tier is ongoing rather than a 7-day trial.
How hard is it to migrate from SelectPdf's REST API to PDFRelay?
Both take a JSON request with HTML or a URL and options like page size and margins. Typical migrations swap the endpoint and auth header and drop the engine-selection parameter, since PDFRelay always renders with Chromium — usually under an hour for a REST API integration.
TRY IT · FREE · NO SIGNUP
See your own markup rendered
Paste your template into the free playground and render a proof in seconds — the exact engine the API uses.
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