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eSigKit · v1

Developer documentation

Everything you need to build with the eSigKit signature-management API — endpoints, authentication, webhooks, and language SDKs. Always in sync with the live spec.

Open API reference Live status

API reference

Every endpoint, request schema, and response shape — generated directly from the production OpenAPI spec.

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Quickstart

Authenticate, render your first signature, and embed it in Gmail in under five minutes.

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Authentication

Cognito JWTs for browser apps, API keys for server-to-server. PKCE flow, token rotation, and the dashboard / admin client split.

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Errors

The full error envelope, status-code catalog, retry guidance per status, and the correlationId pattern for debugging.

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Rate limits

100 RPS stage-wide with 200 burst, plus the 429 + Retry-After contract and exponential-backoff client recipe.

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Idempotency

Optimistic concurrency on every mutable resource — version-based 409 handling and the read-modify-write loop pattern.

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Pagination

Cursor-based pagination on every list endpoint. Opaque base64 cursors, default + max page size, and the loop pattern.

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Webhooks

Stripe-event handling: HMAC signing scheme, 7-day dedup, retry semantics, and the event-type catalog.

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Node SDK

New

Official @esigkit/node — typed client for server-side resolution, users CRUD, optimistic concurrency, and an in-process cache for tight email-send loops.

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Browser SDKs

Drop-in patterns for HTML email signatures, React hooks (useSignature), and Next.js server-component rendering — no API key required.

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Base URLs

Three environments matching the SDLC. Use staging for integration tests; never run automated tests against production.

Stage Base URL Notes
Production https://api.esigkit.com/v1 Live customer traffic.
Staging https://api-test.esigkit.com/v1 Pre-prod validation.
Development https://api-dev.esigkit.com/v1 Sandbox — may break at any time.