Heyzine
DOCS & KNOWLEDGE · FILES & DOCS
Flipbooks converted from PDFs, their design, and bookshelves in the account they connected.
Connecting Heyzine in practice
Heyzine offers the same PDF-to-flipbook conversion in three shapes with different failure behaviour: a link that converts lazily on first access and so cannot report an error at call time, a synchronous POST that blocks for the whole conversion, and an async POST you poll. The free plan allows 5 flipbooks in total, so a handful of test conversions consumes the account.
Scopes that draw scrutiny
Authorization: Bearer <API key>The credential for the REST endpoints at /api1/rest and /api1/async.client_id, passed as the k query parameterThe link-conversion form of the API carries the account’s client id in the URL, so the credential ends up embedded in something designed to be shared.
Rate limits
- No numeric rate limit is published; Heyzine asks for fair use of the API.
- Free plan: up to 5 free flipbooks. Paid subscriptions allow unlimited conversions.
Worth knowing
- Only the async POST lets an agent set its own timeout and poll; the sync POST blocks until conversion finishes and the lazy link defers any error to whoever opens it first.
- The source has to be a direct PDF, DOCX or PPTX URL that Heyzine can fetch, so a document behind authentication must be published somewhere before it can be converted.
- Custom domains, lead generation and bookshelf collections are plan-gated to Professional or Premium, so an agent writing those fields needs the account on the right plan, not just a valid key.
- The base URL is https://heyzine.com/api1 with /rest and /async beneath it rather than a version path, so there is no version to pin a client against.
Checked against Heyzine developers (2026-09-29)
What an agent can do
Each action is granted on its own. An agent allowed to read is not thereby allowed to write, and the scope beside each row is what the acting user must have connected for it to run at all.
Often connected alongside
Put Heyzine behind one governed endpoint.
Same permissions, same audit trail, whatever else you connect next.