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Everything you need to know about Blink PDF, answered in one place. If your question isn’t here, email us at [email protected] and we’ll get back to you promptly.

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General

No. Blink PDF takes Markdown as input and produces a PDF as output. You configure headers, footers, page size, margins, and branding through simple API parameters — there is no stylesheet to write and no LaTeX to learn.If you can write a README, you can use Blink PDF.

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Integration & Compatibility

Blink PDF ships a curated set of hosted families you select per request with the fontStack field — inter (body and headings), jetbrains-mono (code), and the emoji families noto-emoji-mono and twemoji-mozilla. On top of that, you can render body and headings in any Google Fonts family by passing a googleFontsUrl — available on every plan. Fonts are embedded in every PDF so it renders consistently on any device or viewer. Arbitrary custom font uploads are not supported today.For details on selecting fonts and binding roles, see Fonts & Typography.
The maximum input size depends on your plan:Images staged as blink://asset/<id> handles are fetched at render time and do not count toward this limit.If your payload exceeds the limit for your plan, the API returns 413 Payload Too Large. Upgrading your plan increases the limit.

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Privacy & Security

Your Markdown input is loaded into memory for rendering, the PDF is returned to you, and the input is immediately purged — it is never written to disk, logged in plaintext, or stored in a database. Rendered outputs (the PDF, its download link, and any images you stage as assets) are kept for at most 24 hours on every plan to serve delivery and caching, then purged automatically. See Zero Retention for the full breakdown.Enterprise customers can run on dedicated infrastructure with data isolation, a zero-retention output option, and on-premise / VPC deployment for full data sovereignty. See Enterprise.
API keys are hashed with SHA-256 before storage — we cannot retrieve your key in plaintext. If you believe a key has been compromised, rotate it immediately from your account dashboard. Rotating a key invalidates the old one instantly. All API traffic is encrypted with TLS.

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Billing & Plans

Yes — the Free plan is available with no credit card required. You get 250 render units per month (with no daily cap) to explore the API, test your integration, and evaluate output quality. A text render costs 1 unit; image-heavy renders cost more, up to 16. See how billing works.When you’re ready to remove the watermark and increase your volume, you can upgrade to a paid plan at any time from your account dashboard.
Usage is metered in render units, and it depends on your plan and settings:
  • Free — rendering stops once you hit 250 render units for the month. The API returns a 402 error (spend_cap_reached) until the calendar month resets. There is no daily cap.
  • Pro — additional units are billed at $0.004 per unit through Stripe metered billing. If you’ve set a spending cap, rendering stops when the cap is reached instead of incurring overage.
  • Business — additional units are billed at $0.001 per unit.
  • Enterprise — governed by your contract terms; typically dedicated capacity with no per-render metering.
Each paid plan also has a fixed hard cap at 2× its included volume (60,000 units for Pro, 2,000,000 for Business). Overage billing is otherwise soft — you are never abruptly cut off without warning, and you won’t face surprise charges unless you’ve opted into uncapped overage.
You can upgrade, downgrade, or cancel your plan at any time from the billing section of your account dashboard.
  • Upgrades take effect immediately.
  • Downgrades take effect at the start of your next billing cycle.
  • Cancellations — your plan remains active until the end of the current paid period. After that, your account reverts to the Free tier rather than being deleted, so you keep access to your API keys and usage history.
If you’re on an annual plan and need to cancel early, email [email protected] to discuss your options.
When you choose annual billing, the full year’s base subscription is charged upfront as a single payment. You save approximately 17% compared to monthly billing — roughly two months free.Any overage render units you use beyond your included allowance are still billed monthly at the end of each calendar month, at the same per-unit overage rate as the monthly plan.
No. Health-check requests and POST /v1/render/validate calls are free and never consume render units. Only successful POST /v1/render and POST /v1/templates/*/render responses billed as counted (in the X-BlinkPDF-Billing header) consume units — cache and idempotent replays on /v1/render do not. Note that validation has its own rate-limit bucket, so a validate burst can still return 429.