# Waku's Requirements on Codex

## Publish Large Messages - Uploader is online

To be used for messages archival in Chat SDK, Qaku, opchan, etc.

### Functionality

1. Ability to transfer a message of 1MB or more between two or more nodes.
2. Message's CID is less than 100kB.


### Usability

1. Developer can implement upload feature with 10 lines of code or less.
2. No configuration is necessary.

### Reliability

1. Download operation can be resumed.
2. Upload operation can be resumed.
3. Uploader can be expected to be online when user are downloading.

### Performance

None

### Supportability

1. Library for Browser applications.
2. Library for Nim desktop applications.
3. Library for Nim mobile applications.

**+ (Privacy, Anonymity, Censorship-Resistance, Deployments)**

1. The unavailability of a static host (IP, DNS) does not prevent a user to upload or download (censorship-resistance).
2. TODO (privacy)

## Publish Large Messages - Uploader is offline

To be used for

- large messages transfers (such as images, videos, audio) in Chat SDK, Opchan, etc.
- Enhancement of message archival (uploader does not need to be online for messages to be retrieved).

Builds on [Publish Large Messages - Uploader is online](#publish-large-messages---uploader-is-online)

### Functionality

1. Message is cached to enable retrieval without sender being online (once uploaded).
2. Best effort in terms of message retention; expectations on restrictions are documented.

### Usability

1. Receiver can download the large message, even if sender is offline, as long as they get the CID out-of-band.

### Reliability

1. Uploader may be offline when receiver is retrieving the large message.

### Performance

None

### Supportability

1. Library for Browser applications.
2. Library for Nim applications.

### + (Privacy, Anonymity, Censorship-Resistance, Deployments)**

TODO (privacy)

## Publish Large Messages - Retention is guaranteed

In this scenario, the uploader wants to ensure the data is persisted and is willing to pay for it.
This may be a Qaku Q&A admin, a opchan cell owner or Status Communities owner.

Builds on previous requirements.

### Functionality

1. Uploader may pay for large message storage to have guaranteed retention.

### Usability

1. Receiver can download the large message, even if sender is offline, as long as they get the CID out-of-band.
2. Receiver does not need to pay to retrieve the large message.

### Reliability

1. Uploader may be offline when receiver is retrieving the large message.
2. Uploader is guaranteed a period of retention for a given price.

### Performance

See previous requirements.

### Supportability

See previous requirements.

### + (Privacy, Anonymity, Censorship-Resistance, Deployments)**

See previous requirements.