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Pressline

The protocol

An Engine is any HTTP service that serves, under a base URL the Operator configures:

Answer
GET /health { protocolVersion: "1" }
GET /designs/{id} { id, title?, sellable, previewUrl, aspect: { w, h }, offers?, mockups?, engineRef? } or 404 DesignNotFound
POST /designs/{id}/printfile with a Printfile Spec 200 { status: "ready", url, sha256, width, height, bytes, contentType, specHash }, or 202 { status: "rendering", retryAfterMs }, or 422 PrintfileRejected { code, message }

Every request carries Authorization: Bearer <shared secret>. The exact schemas are the normative source in @pressline/contract, which also ships a typed client and an Effect HttpApi you can implement directly.

A Printfile Spec is what Pressline derives from a Printful placement: { width, height, dpi, formats, colorSpace: "srgb", alpha: "allowed" | "forbidden" | "required", placement, technique }. Its Spec Hash (specHash(spec) in the contract) together with the Design ID identifies exactly one Printfile and is the idempotency key: the same request must return the same URL and echo the same specHash.

  • aspect is the design’s own shape; Pressline hides Offers whose print area does not fit it, and your Engine answers 422 aspect_mismatch to a Spec it cannot honor.
  • offers (Offer slugs) narrows which Offers the design may be sold on; omit it for “all”.
  • mockups[offerSlug] is an optional image of the design on that product, shown instead of Pressline’s overlay.
  • sellable: false stops new orders without deleting the design.