> For the complete documentation index, see [llms.txt](https://docs.emudhradigital.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.emudhradigital.com/api-reference/esign-v2-api-online-aadhaar/esign-v2-api-overview.md).

# eSign v2 API Overview

The eSign v2 API implements **CCA eSign API 2.1 (Online Aadhaar & Others)**. One document hash is signed per request after Aadhaar authentication by OTP / T-OTP, fingerprint, iris or face.

{% hint style="info" %}
**Interactive reference (Swagger / OpenAPI):** [eSign v2 API — Swagger](https://todo-swagger-url/esign-v2)

*Placeholder link — to be replaced with the published Swagger URL.*
{% endhint %}

## Operations

| # | Operation             | Method / transport                           | Payload                  |
| - | --------------------- | -------------------------------------------- | ------------------------ |
| 1 | Submit sign request   | HTTPS POST (browser form, app intent or SDK) | Signed `<Esign>` XML     |
| 2 | Signer authentication | eMudhra-hosted pages / SDK                   | —                        |
| 3 | Receive response      | HTTPS POST to `responseUrl`                  | Signed `<EsignResp>` XML |

## Flow

1. ASP hashes the document and builds a signed `<Esign>` request.
2. Request is posted to the eMudhra eSign gateway.
3. Signer gives consent and authenticates with Aadhaar.
4. eMudhra issues a one-time DSC (≤ 30 min), signs the hash and destroys the key.
5. Signed `<EsignResp>` is posted to `responseUrl`.

## Key limits

| Item                  | Value                                                 |
| --------------------- | ----------------------------------------------------- |
| Documents per request | 1                                                     |
| Hash                  | SHA-256 (hex)                                         |
| AuthMode              | `1` OTP/T-OTP · `2` fingerprint · `3` iris · `4` face |
| Timestamp tolerance   | ±30 minutes                                           |