> For the complete documentation index, see [llms.txt](https://guide.letters.gov.sg/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guide.letters.gov.sg/for-agency-users/faqs.md).

# FAQs

## General

<details>

<summary>What is the difference between LetterSG, Postman, and Postman Legacy?</summary>

| LetterSG                                                                                                               | Postman                                                                                                                                       | Postman Legacy                                                                                                                    |
| ---------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------- |
| Helps public officers to issue and send personalised & verifiable digital official communications to citizens quickly. | Postman (postman.gov.sg) is a mass broadcasting communication tool for public officers to reach citizens via SMS, using the gov.sg sender ID. | Postman Legacy (legacy.postman.gov.sg) is a mass broadcasting communication tool for public officers to reach citizens via email. |

</details>

<details>

<summary>What is the difference between LetterSG and FileSG/ TrustDocs/ OpenAttestation?</summary>

| LetterSG                                                                                                               | FileSG/ TrustDocs/ OpenAttestation                                                                       |
| ---------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| Helps public officers to issue and send personalised & verifiable digital official communications to citizens quickly. | Offers tamper-proof certifications on the blockchain that meet international standards for verification. |

</details>

<details>

<summary>How can we check if the recipient has read the letter?</summary>

You will be able to check the read status of the letter via your LetterSG dashboard. After logging in,  click on **Dashboard** → Select the relevant batch → Find the relevant recipient letter → `Read` status column.

</details>

<details>

<summary>Is there a maximum limit for the number of letters that can be sent via LetterSG?</summary>

Currently, we support a maximum batch size of 500 letters. If you have more recipients, consider splitting your recipients into multiple batches of 500 for issuance.

</details>

<details>

<summary>How long will the letters be accessible for?</summary>

Letters issued will be accessible at all times and will not expire.

</details>

## Security

<details>

<summary>What is the security and sensitivity classification of LetterSG?</summary>

We can handle up to Restricted (Sensitive-Normal) data.&#x20;

Please note that letter links can be accessed by anyone who has them.

</details>

<details>

<summary>Is it safe to send out LetterSG links to citizens?</summary>

Links ending with ".[gov.sg](http://gov.sg/)" are allowed in SMSes to citizens.

</details>

<details>

<summary>When should/shouldn't I use LetterSG?</summary>

LetterSG should only be used for **documents that can be safely shared in public**, where any unintended exposure would have minimal impact on your agency or recipients. Anyone with the link can access the e-letter, so **please avoid using LetterSG for private or confidential documents**.

While we ensure the LetterSG platform is secure, we cannot prevent third parties (individuals or automated systems) from exposing links. This can happen if a recipient publishes the link, or if a third-party application on their device inadvertently “leaks” it. In such cases, LetterSG will not carry out remediation (e.g., proactive web scans or link takedowns). If removal is necessary, agencies may contact the relevant platforms or services directly.

</details>

<details>

<summary>Where is the data on LetterSG stored? </summary>

It is stored on servers in Singapore, complying with IM8 policy.

</details>

<details>

<summary>Can we attach our signature at the end of the letter?</summary>

We do not allow the hosting of digital signature images on our platform as it could be a potential security risk. Instead, we advise our users to use the Brush script font as a digital signature. The document is recognised as a valid e-document as it is issued on a .[gov.sg](http://gov.sg) domain.

</details>

## Getting started

<details>

<summary>I've issued a test letter and opened the letter link to check the contents. When viewing the dashboard, why doesn't the letter's read status change to "Read"?</summary>

If you're logged in as an agency user, we do not register an update to the read status for a letter. This is to allow agency users to check the contents of the letter without accidentally registering a "Read" count. \
\
To test for a status update, please open the letter in a separate device or log out of [letters.gov.sg](https://letters.gov.sg/) beforehand.

<figure><img src="https://4097645561-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FUGChNUU8J3OerY8QoGh6%2Fuploads%2FP055quwlygvPA45hEhrl%2FScreenshot%202024-09-24%20at%209.46.09%E2%80%AFAM.png?alt=media&amp;token=9636bfbe-716a-4d7c-904e-eb3a49f123e4" alt=""><figcaption><p>If you see this at the top of the letter, you will not see an update to the read status as you are logged in as an agency user. Log out of letters.gov.sg or open the letter link in incognito to test the read receipt.</p></figcaption></figure>

</details>

## Sending letters via email and SMS

<details>

<summary>Can we change the title name and content in the letter email and SMS notifications?</summary>

Outgoing emails sent via LetterSG will have the email title *”**Letter from {{template\_name}}**” .* We are unable to customise the body of the email any further as it is intentionally standardised for all outgoing emails from LetterSG to improve legitimacy and readership of letters.&#x20;

However, if you need to change the copy in the outgoing email/SMS to your recipients, you could choose to create letter links in bulk using "Other services". You could then subsequently use [Postman](https://postman.gov.sg) (for SMS) or [Postman Legacy](https://legacy.postman.gov.sg) (for email) where you would be able to set your own email/SMS copy, and embed the generated LetterSG letter link within the email/SMS.

</details>

<details>

<summary>Can we customise the logo and agency information in the letter email and SMS notifications?</summary>

The logo and agency name cannot be customised as it is automatically determined based off your user email domain.&#x20;

If you'd like to update the logo or have other concerns, please write to our team via this [form](https://go.gov.sg/lettersg-support).&#x20;

</details>

<details>

<summary>Can we change the reply-to email address in the letter email notification?</summary>

The reply-to email address will correspond to the email address of the user who sent the letters. Users can consider using a shared team email address to issue the letters.

</details>

<details>

<summary>Can we resend a letter to the same recipient?</summary>

We do not support resending of the same letter to recipients to prevent spamming. If you wish to use the same letter, you can consider sharing the original letter link with the recipient, or using Postman to send another SMS or email containing this letter link, to the same recipient.&#x20;

Alternatively, you may issue a new letter to the recipient which will generate a new letter link.

</details>

<details>

<summary>Can we use our agency sender ID to send SMSes?</summary>

From June 2024, all SMSes will be sent using [gov.sg](https://gov.sg) sender ID under securing government wide communications initiative. This is only applicable to users under the BTN mandate, which does not apply to schools or Public Healthcare Institution users.

For schools or Public Healthcare Institution users, you may be able to use an approved custom sender ID if you are sending SMSes from your own system/SMS service provider.

</details>

<details>

<summary>How are SMSes sent from LetterSG?</summary>

LetterSG supports sending of letter links via SMS directly through the platform. This is done by linking LetterSG to [Postman](http://postman.gov.sg/) in the backend. SMSes are then sent from the [gov.sg](http://gov.sg/) sender ID.

</details>

<details>

<summary>What is the cost involved with using the SMS function?</summary>

Today, LetterSG sends each user’s SMSes through OGP’s [Postman](https://postman.gov.sg) account, with cost covered by OGP. This means that SMSes are currently free.

{% hint style="warning" %}
**\[Updated 29 Oct 2026]** SMSes sent from LetterSG will be chargeable **from 1 Apr 2027**. This will be done by allowing users to connect a Postman SMS campaign to their LetterSG templates.

* With the current arrangement, users cannot control SMS sending access for each template. This is especially since LetterSG templates can be shared across agencies.
* The Building Trusted Networks (BTN) mandate requires all government users to send SMS from the [gov.sg](http://gov.sg) sender ID. [Postman](http://postman.gov.sg) already manages [gov.sg](http://gov.sg) SMS this way.
* Hence, we are aligning LetterSG with Postman in 3 areas:
  * **Access control:** Users decide who can send SMSes on LetterSG as they are in control of the SMS campaign.
  * **Accountability:** Every SMS is tied to your/your agency’s Postman SMS campaign.
  * **Billing:** Each agency pays for its own SMS sending needs.
    {% endhint %}

</details>

<details>

<summary>Can we add attachments / images / files / PDFs to letters?</summary>

We do not support attachments in the letter currently. If you would like to add files which are not of a sensitive nature, we recommend uploading the files on [GoGov](https://go.gov.sg) first, generating a GoGov link and then adding that link into the letter content itself.

</details>

<details>

<summary>Can I send SMSes from LetterSG if I am a schools or Public Healthcare Institution (PHI) User?</summary>

Currently, schools and PHI users can use the [LetterSG SMS function](https://app.notion.com/p/FAQ-For-Agency-Users-40777dbba78880229110e41cf1bda379?pvs=21). However, per the Building Trusted Networks ([BTN) mandate](https://docs.developer.tech.gov.sg/docs/postman-sgdp-guide/introduction-to-btn?product=Postman), primary and secondary schools, as well as junior colleges, should not be using Postman. It is also publicly communicated on [sms.gov.sg/check](http://sms.gov.sg/check) that MOPs should not be expecting SMSes from primary and secondary schools, as well as junior colleges, from the [gov.sg](http://gov.sg) sender ID. The sender ID is the name of the sender that recipients see.

<figure><img src="https://4097645561-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FUGChNUU8J3OerY8QoGh6%2Fuploads%2FBqrPdsa7xSKDOPbdszFY%2Fimage.png?alt=media&amp;token=5af19e69-55a0-4909-a68d-8796fe403af3" alt=""><figcaption></figcaption></figure>

**For schools**

If you are a schools user, you may still be sending SMSes from the [gov.sg](http://gov.sg) sender ID via LetterSG. MOE will contact schools users directly on the transition to a [non-gov.sg](http://non-gov.sg) sender ID.

**For PHIs**

Currently, when PHIs send SMSes via LetterSG, it is via the LetterSG sender ID, which is owned by OGP.

**For both schools and PHIs**

We plan to decommission the LetterSG sender ID from **1 April 2027**. This means that from this date, schools and PHIs can continue to use LetterSG to create and [send letters via email or letter link generation](https://guide.letters.gov.sg/for-agency-users/sending-out-letters), but the SMS feature will stop. Hence, if a school or PHI wants to send letter links by SMS, they must use its own system/SMS service provider.

</details>

## Others

<details>

<summary>I am unable to receive an OTP/ unable to log into LetterSG. What should I do?</summary>

Please write to our team via this [form](https://go.gov.sg/lettersg-support). We will get back to you as soon as we can.

</details>

<details>

<summary>I am interested in using LetterSG but I am unable to register or log in. What should I do?</summary>

LetterSG is only available for public officers. For schools, we are only available for use in (i) [Polytechnics or ITEs](https://www.sgdi.gov.sg/ministries/moe); or (ii) [government-funded schools](https://www.moe.gov.sg/schoolfinder).&#x20;

If you have an email address with a government agency domain but are unable to log in, please write to our team via this [form](https://go.gov.sg/lettersg-support). We will get back to you as soon as we can.

</details>

<details>

<summary>I cannot find an answer to my question on this guide. What should I do?</summary>

Please write to our team via this [form](https://go.gov.sg/lettersg-support). We will get back to you as soon as we can.

</details>