Hosting the relayer and indexer (owner steps)

The live website runs on Vercel. Two optional services make it complete for visitors:

• the relayer (gasless trading), hosted on Railway;
• the indexer (full history).

Both need an account in the owner's name, which the agent cannot create. Everything else is prepared in the repository. Nothing here is deployed until the owner does the steps below.

1. Relayer on Railway (gasless trading)

What is prepared

Verified locally on 2026-10-13 from a fresh clone of commit 509fa84, with a throwaway, unfunded key generated inside the build machine and never printed:

• image builds;
• logs listening on 0.0.0.0:9911 with the allowed origin;
• /health returns 200 with chain 10143;
• preflight from https://imprest-chi.vercel.app returns 204 and echoes that origin;
• preflight or POST from another origin returns 403;
• a forged signature returns 401 INVALID_SIGNATURE;
• a wrong chain returns 400;
• no .env or key file in the image.

Replay protection (nonce), deadline and the per-trader quota are covered by relayer/test (14 tests) and re-checked by the Desk contract onchain.

The origin allowlist only stops other websites' browsers. It is not authentication: a script without an Origin header can still reach the relayer. What actually protects the gas wallet:

• every intent must carry the desk trader's EIP-712 signature;
• the desk must be an Imprest desk;
• the nonce must be unused and the deadline unexpired;
• the per-trader quota and the gas cap apply;
• the order is simulated before it is sent.

Environment variables

Key:

• Use the existing dedicated relayer wallet 0x017F46FdCC2fC946D7e1f86927Aa37267331b728. It is

testnet-only, holds about 4.83 testnet MON and nothing else.

• Its key is RELAYER_PRIVATE_KEY in your local .env.
• Never use a key that holds real funds.
• Stop any local relayer once the hosted one runs. Both would use the same wallet, so running both

can produce nonce clashes.

Steps

1. Sign in at https://railway.com with GitHub. Check the current trial and plan terms; do not

buy anything for this.

1. New Project → Deploy from GitHub repo → allow Railway's GitHub app access to

TheWeirdDee/imprest → choose it. Railway reads railway.json and builds the Dockerfile. The first deploy fails until the key is set; that is expected.

1. Open the service → Variables → add the four public variables above. Then add

RELAYER_PRIVATE_KEY, paste the value from your .env and seal it. Railway redeploys.

1. Settings → Networking → Generate Domain. If it asks for a port, use the one in the deploy log

line listening on 0.0.0.0:<port>.

1. Open https://<domain>/health. Expect "ok":true, "chainId":10143 and

"relayer":"0x017F…b728". Send the domain to the agent.

1. The agent then:

• verifies health, logs and CORS from the live origin;
• sets NEXT_PUBLIC_RELAYER_URL in Vercel and redeploys, or gives you that step.

A health check is not gasless execution. That is only shown by a trade the trader signs in the browser, relayed, mined and verified on the second RPC.

2. Indexer on Envio (full history)

Prepared: indexer/. Its config is generated from config/networks.json and validated against Envio's schema; the schema and handlers are included. Backfill starts at the deployment block, 69010507.

indexer/pnpm-lock.yaml lets the folder install on its own, outside the pnpm workspace.

1. Sign in at https://envio.dev with GitHub and check the current plans (Development tier is used).
2. Connect Repository: authorize the Envio GitHub app for TheWeirdDee/imprest.
3. Cloud → Projects → on the theweirddee/imprest row, + Add indexer: name imprest-indexer,

root directory indexer, config config.yaml, branch main, no environment variables. The config syncs Monad testnet (chain 10143) over the public RPC in 100-block windows.

1. Envio deploys on every push to main. Wait for the sync to reach the chain head; Envio shows

progress.

1. Copy the GraphQL endpoint into Vercel as NEXT_PUBLIC_INDEXER_URL and redeploy.
2. Check that /status shows "Indexer LIVE" with the processed block, and that History shows the

transactions from 2026-10-09 and 2026-10-12.

Status, 2026-10-13: not working, left open. Deployed on Envio's free Development plan (commits f93e328, a1db37f, cb7c1db). Every deployment stayed at block height 0, with 0 events and "Indexing Has Stopped", including with independent RPCs (dRPC, Ankr) that answer eth_blockNumber and 100-block eth_getLogs normally from elsewhere. Envio v3 needs ENVIO_API_TOKEN for HyperSync, and setting environment variables on the hosted service is a paid feature. Envio's log viewer timed out (504), so the exact error was not visible. Nothing was bought.

The website does not need the indexer: History falls back to a bounded, read-only chain scan in 100-block windows and says when its coverage is partial. To finish this later, either:

• read the deployment logs once Envio's viewer loads, and fix the reported error; or
• run the indexer where ENVIO_API_TOKEN can be set (locally under WSL, or a paid plan).

3. Keeper

The keeper needs to run continuously. Options:

• an always-on instance;
• a small VPS;
• leave it as is: the contracts do not depend on it. Enforcement and graduation are open to

anyone, and the website's Graduate button calls the same function.