SDK API

The SDK API is organized by invocation context — each page documents the wrappers available during that entry point.

• Common — available in all contexts (ServiceData, Preimages)
• Refine — RefineContext, RefineFetcher, RefinePreimages, Machine
• Accumulate — AccumulateContext, AccumulateFetcher, AccumulatePreimages
• Authorize — AuthorizeContext, AuthorizeFetcher
• Utilities — Logger, LogMsg, ByteBuf, Decoder, Byte Types
• Host Calls (ecalli) — raw host call reference table

Example services

Each example in examples/ is a self-contained service that exercises a particular slice of the SDK. Browse the source for end-to-end patterns.

• fibonacci — minimal refine + accumulate, starter template.
• authorizer — standalone is_authorized service with gating logic.
• ecalli-test — dispatches every ecalli host call for smoke-testing the SDK surface.
• all-ecalli — self-authorizing service that invokes every ecalli across refine, accumulate, and authorize entry points.
• pastebin — open-submission paste service. Refine hashes the payload with Blake2b-256; accumulate solicits the preimage and records metadata in a storage-backed ring buffer plus a slot-bucketed TTL index. Preimage bytes arrive via the xtpreimages block extrinsic — accumulate never calls provide. Good reference for the solicit-only preimage lifecycle and slot-bucket cleanup patterns.
• library — hosts reusable PVM verification blobs as SPI-encoded preimages keyed by name, resolved and executed via ctx.nestedPvmFromSpiChecked(...).
• nested-pvm-spi — minimal smoke test for the inner PVM: loads an embedded SPI blob and runs it through ctx.nestedPvmFromSpiChecked.