# NextSign API Documentation
> Official NextSign API documentation for authentication, forms, cases, documents, webhooks, and test integrations.

NextSign publishes API documentation for authentication, forms, cases, documents, file handling, test integrations, versioning, rate limits, idempotency, and webhooks.

Important notes:

- Cases and forms are primarily documented under `https://www.nextsign.dk/api/v2/...`.
- File upload and file retrieval endpoints are documented under `https://api.nextsign.dk/v3/...`.
- Use the exact endpoint path documented for each operation instead of assuming that all resources share the same version or host.
- Older `v2` endpoints can return application-level errors in the JSON body, so integrations should validate both HTTP status codes and the response payload.

## Start Here

- [Introduction](https://docs.nextsign.dk/docs): Overview of the NextSign API surface, integration model, and reference index.
- [Authorization](https://docs.nextsign.dk/docs/authorization): How to create an API key, send bearer tokens, and locate the company ID.
- [API Versioning](https://docs.nextsign.dk/docs/versioning): How documented `v2` and `v3` endpoints differ and why they should be treated as separate contracts.
- [Test Environment](https://docs.nextsign.dk/docs/testenv): How to test safely before sending production traffic.
- [OpenAPI JSON](https://docs.nextsign.dk/openapi.json): Beta machine-readable contract for the documented API surface.

## Getting Started

Authentication, environments, and the fastest way to make your first request.

- [Introduction](https://docs.nextsign.dk/docs): Complete API documentation for automating forms, cases, document signing, and file retrieval using NextSign.
- [Authorization](https://docs.nextsign.dk/docs/authorization): Find your API key and companyId, and authenticate requests to the NextSign API.
- [Test Environment](https://docs.nextsign.dk/docs/testenv): Build and validate your NextSign integration safely without affecting production data.

## Platform

Versioning, rate limits, and idempotency guidance for reliable integrations.

- [API Versioning](https://docs.nextsign.dk/docs/versioning): Understand how NextSign versions endpoints and how to safely work with both v2 and v3 routes.
- [Rate Limits](https://docs.nextsign.dk/docs/rate-limits): Understand the current NextSign API request limit and how to build retry-safe clients around it.
- [Idempotency](https://docs.nextsign.dk/docs/idempotency): Understand the difference between request idempotency, resource IDs, and webhook deduplication in NextSign.

## Forms

Retrieve templates, inspect tags, and submit forms to create signing cases.

- [Forms Get](https://docs.nextsign.dk/docs/forms-get): Get a form by ID using GET /api/v2/{company}/forms/{form_id}/get.
- [Forms Tags](https://docs.nextsign.dk/docs/forms-tags): Get form tags using GET /api/v2/{company}/forms/{form_id}/tags/get.
- [Forms Submit](https://docs.nextsign.dk/docs/forms-submit): Submit a form using POST /api/v2/{company}/forms/{form_id}/submit.

## Cases

Create, list, inspect, and manage signing cases across their lifecycle.

- [Case List](https://docs.nextsign.dk/docs/cases): List cases with filters using GET /api/v2/{company}/cases/get.
- [Case Get Multiple](https://docs.nextsign.dk/docs/cases-get-multiple): Get multiple cases by ID using GET /api/v2/{company}/cases/{case_ids}/get.
- [Case Get](https://docs.nextsign.dk/docs/case): Get a single case by ID using GET /api/v2/{company}/case/{case_id}/get.
- [Case Create](https://docs.nextsign.dk/docs/case-create): Create a case using POST /api/v2/{company}/case/create.
- [Case Delete](https://docs.nextsign.dk/docs/case-delete): Delete a case using GET /api/v2/{company}/case/{case_id}/delete.

## Documents

Upload larger files, retrieve signed files, and convert source documents before they are sent.

- [Document Upload](https://docs.nextsign.dk/docs/documents-upload): Upload a file using POST /v3/company/{company}/file/upload.
- [Document Retrieve](https://docs.nextsign.dk/docs/documents): Retrieve a pre-signed document URL using POST /v3/company/{company}/file/view-presigned-url.
- [Document Convert](https://docs.nextsign.dk/docs/documents-convert): Convert documents using POST /api/v2/document/convert.

## Events

Subscribe to lifecycle notifications and understand webhook delivery retries.

- [Webhooks](https://docs.nextsign.dk/docs/webhooks): Receive real-time notifications when case and flow events occur in NextSign.
- [Webhook Retry Logic](https://docs.nextsign.dk/docs/webhook-retry-logic): Understand how NextSign retries failed webhook deliveries and how to build duplicate-safe handlers.