FirstLight docs for Robinhood Chain

Robinhood Chain feeds and submission from FirstLight: the sequencer feed, its raw transactions and its block headers, and your transactions sent to the sequencer. These pages tell you how to connect, what each stream sends and how to verify the timing yourself.

Plans, streams and products

Plan	What you get	Docs
Free	The `/headers` stream, to verify FirstLight's timing. A block's Lead arrives at about the time of its first raw transaction on `/tx`, and its Footer within about 0.1 ms of the complete block on the feed. A block can have no Lead.	Headers
Pro	The feed: the standard Arbitrum Nitro feed of Robinhood Chain.	Feed
Ultra	Everything in Pro, raw transactions on `/tx`, each as soon as its bytes complete, usually before its block completes, and FirstLight Submit for your transactions. Colocation in AWS Ohio.	Feed, Transactions, Submit, Colocation

See the plans for what each plan includes.

Endpoints

Stream or product	URL	Key's stream
Feed	`wss://blocks.first-light.stream/{KEY}`	`blocks`
Raw transactions	`wss://tx.first-light.stream/{KEY}`	`tx`
Headers	`wss://headers.first-light.stream/{KEY}`	`headers`
Submit	`https://submit.first-light.stream/{KEY}`	`submit`

The host name chooses the stream, and the path is the key: / followed by the key. The relay ignores a query string. Submit also takes the key as Authorization: Bearer {KEY} with the path /.

Keys

One key gives access to the streams of your plan. Ask for a key on Telegram. A free key for /headers comes first.

Key format

A key is 53 characters: fl_, 43 base62 characters, _, and a 6-character base62 checksum. The relay checks the shape and the checksum before it looks up the key, so a mistyped key gets 404.

fl_<43 base62 characters>_<6 base62 characters>

Rules

Keep your key secret. Anyone who has your key can use it until we revoke it.
A key names the streams that it may read. A key without the stream of a host gets 403.
A key may hold a fixed number of connections on each stream. A new connection over that number takes the place of your oldest one. Do not share one key between two clients.
A key can have an expiry. An expired key gets 401, and its open connections close with code 4003.
We name a key by a short ID in our records. We do not record the key itself.

Start in three steps

Ask for a free key on Telegram.
Connect to wss://headers.first-light.stream/{KEY} and stamp each record on your own clock.
Compare the arrival of each block with the feed that you use today. See how FirstLight is measured.

What FirstLight does not do

FirstLight does not change how the sequencer orders or includes transactions. Robinhood Chain orders transactions first come, first served at the sequencer. FirstLight changes when you learn what the sequencer did.