How to Set a Custom RPC in GMGN (and What It Will Not Fix)

When a Custom RPC Is Worth Setting, and When It Changes Nothing

The honest framing is narrow. GMGN describes the RPC node's job as transaction submission, sending transactions to the blockchain for validation and recording. That is the whole of what the setting touches. Everything that decides whether your trade fills at a price you like happens before or after that step.

So it is worth setting when your problem is genuinely about the submission path: you run infrastructure of your own, you have an endpoint you trust more than a shared default under load, or you want a second route on the chain at the same time as GMGN's. GMGN's own wording is that the custom RPC "will be used as a backup RPC for simultaneous on-chain submission," so what you get is redundancy, not a detour.

It changes nothing at all in three cases that people reach for it in:

• Fees. GMGN charges a flat 1% per transaction on the buy and again on the sell. The custom RPC section states that "if a custom RPC is used for submission, both priority and tip fees will be charged at the same rate." Nothing gets cheaper.
• Slippage. Slippage is a tolerance you authorize, not a network property. A 50% setting authorizes a fill half a level below the quote whichever endpoint carries it.
• Most documented failures. GMGN's error table attributes A1 to a low priority fee and A2 to low slippage. Those are settings.

Where the Setting Lives

There is no separate RPC screen. GMGN documents the field in section 5 of its Fees and Settings page, headed "Priority fee, Tip fee, Custom RPC," which is the same panel you open to set the two fee values before a trade. The Anti-MEV RPC submission control sits in the same block.

The row under the Buy button is the one to look at. It shows the current slippage mode, the priority fee value and the Anti-MEV state, and the settings control beside it opens the panel where all of those and the custom RPC field live. The capture above is a logged-out session, which is why the balance reads zero.

Setting It, Step by Step

Choosing an Endpoint

This site does not rank RPC providers and GMGN's documentation names none, so what follows is a description of what to compare rather than a recommendation.

The endpoint's job here is narrow: accept a signed transaction and get it in front of validators. Submission latency is mostly geography and peering, so an endpoint two hops away will usually beat a better-marketed one on another continent, and that is worth checking before anything on a pricing page is.

The property people skip is behavior under load. Memecoin trading is a burst workload, and the minute you care about is the minute everyone else is also submitting, which is exactly when a shared endpoint starts shedding requests. What a provider does at its rate limit tells you more than its headline throughput does. That matters more again if you run auto buy or copy trading, because then the request rate is set by the market rather than by you.

Verifying It Took Effect

GMGN's documentation does not describe a confirmation indicator for the custom RPC field, so there is no in-app light to look for. What it does describe is the transaction hash as the place to see what a trade actually did, and that is the check available to you.

Place one small trade, open its signature on Solscan, and read the fee lines. You are looking for the priority fee and tip you set, at the values you set them, which is the documented behavior when a custom RPC carries the submission. If those values are not what you chose, the setting is not your problem: the fee fields are.

What This Does and Does Not Fix

A summary, because the misconception this setting attracts is expensive.

It can help with: a submission path you have a specific reason to distrust, and redundancy on the way to the chain, since GMGN submits through both simultaneously.

It does not touch: the flat 1% handling fee, the priority fee, the tip fee, gas, slippage, the price you are quoted, or the launchpad's own cut on a token issued through Pump.fun or another platform.

It is not the documented fix for: A1 timeouts, which GMGN attributes to a low priority fee; A2 timeouts, attributed to low slippage; C1 execution failures, where the transaction reached the chain and reverted on slippage while still consuming gas; or D1 to D3 route errors, where no trading route exists at all. Every one of those has a different documented remedy, and they are worked through code by code in GMGN transaction failed.

If you are here because trades keep failing, start with that table rather than with this field. The three settings GMGN itself tells failed users to check first are slippage, priority fee and Anti-MEV, in that order, and none of them is an endpoint.

Nothing here is financial, tax or legal advice, and none of it is a statement about what any setting will do to a particular trade. GMGN revises its documentation without notice, so confirm the current wording in its own Fees and Settings page before you rely on any of the above.