---
id: TIP-1030
title: Allow same-tick flip orders
description: Relaxes the placeFlip validation to allow flipTick to equal tick, enabling flip orders that flip to the same price.
authors: Dan Robinson
status: Draft
related: TIP-1002
protocolVersion: T5
supersedes: TIP-1002
---

# TIP-1030: Allow same-tick flip orders

## Abstract

Relaxes the `placeFlip` validation to allow `flipTick == tick`, enabling flip orders that flip to the same price. This supersedes TIP-1002, extracting the "allow same-tick flip orders" portion without the "prevent crossed orders" change.

## Motivation

Currently, `placeFlip` requires `flipTick` to be strictly on the opposite side of `tick` (e.g., for a bid, `flipTick > tick`). This prevents use cases like instant token convertibility, where someone wants to place flip orders on both sides at the same tick to create a stable two-sided market that automatically replenishes when orders are filled.

---

# Specification

## Modified behavior

The `placeFlip` validation is relaxed to allow `flipTick == tick`:

- **Current behavior**: For bids, `flipTick > tick` required; for asks, `flipTick < tick` required
- **New behavior**: For bids, `flipTick >= tick` required; for asks, `flipTick <= tick` required

## Events

No new events.

## New errors

No new errors.

# Implications

- **Locked books**: Same-tick flip orders can result in `best_bid_tick == best_ask_tick`. This forecloses any future upgrade that would forbid bids and asks from resting at the same tick, since same-tick flip orders legitimately create that state.
- **MEV**: Tighter flip orders (where `flipTick` is closer to or equal to `tick`) increase the likelihood of certain kinds of MEV, such as backrunning, since the new opposite-side order appears at a better price for the backrunner.

# Invariants

- Flip orders with `flipTick == tick` are accepted and behave like any other flip order
- Flip orders with `flipTick` strictly on the wrong side of `tick` are still rejected