Do trust lines cost money?

They hold 0.2 XRP of your balance in reserve; it is not spent, and it is free again when the line is removed. Opening one costs a network fee of about 0.000012 XRP.

Can a trust line let the issuer take my XRP?

No. The line only concerns that one token. What the issuer may be able to do is freeze or claw back its own token, if it set that up; the token safety guide shows how to check.

Why can’t I remove a trust line?

The line must be back to its default state: a zero balance and a zero limit. A tiny leftover balance is the usual cause; send it back to the issuer, then remove the line again.

Do I need a trust line for every token?

For every token issued with trust lines, yes, one per token. Multi-purpose tokens use a similar holder entry, and NFTs need none.

Insights

What Is an XRPL Trustline?

On the XRP Ledger you choose which tokens you will hold. A trust line is that choice: your account’s permission to hold one token from one issuer, up to a limit you set. Without it, nobody can send you that token.

Your account

signs to open the line

Trust line

Token: one currency code from one issuer
Limit: the most you agree to hold
Balance: what you hold now
No Ripple: on: nobody can route other payments through you

Holds 0.2 XRP of your balance in reserve while it exists.

Issuer

creates the token; may be able to freeze or claw it back

One trust line is one entry on the ledger between two accounts (xrpl.org).

Why tokens need one

A token on the XRP Ledger is a balance between you and its issuer, and the ledger keeps that balance in the trust line (xrpl.org). Because only you can open the line, nobody can push an unwanted token into your account (why tokens can’t be airdropped).

What it costs

0.2 XRP held in reserve per line, not spent: it is free again when the line is removed.
The first two lines are an exception: an account holding just the 1 XRP base reserve can still open them (xrpl.org, rippled).
About 0.000012 XRP network fee to open or change a line.

Ten lines hold 2 XRP on top of the base reserve (reserves explained).

The setting that matters: No Ripple

With No Ripple off, your account can be used as a stop on someone else’s payment: if you hold two tokens with the same code from different issuers, a payment can take one and leave you the other, at one for one, without your signature (rippling). A worthless copy of a token can be swapped for the real one this way. xrpl.to sets No Ripple on every line it opens; with another wallet, check that it does too.

Opening one on xrpl.to

Buying opens it for you. The first buy of a token opens its line in the same step, and selling all of it removes the line again.
To receive a token first (a transfer or an airdrop), open the token’s page and choose Set Trustline in its ⋯ menu.

Removing one

A line disappears once it is back to its default state: zero balance, zero limit and default settings (xrpl.org). Sell or send the whole balance, then remove the line. A leftover amount too small to sell keeps the line open; on xrpl.to, a token page offers to remove the line once you hold less than one token, sends that leftover back to the issuer and frees the 0.2 XRP in one go.

Questions

Do trust lines cost money?: They hold 0.2 XRP of your balance in reserve; it is not spent, and it is free again when the line is removed. Opening one costs a network fee of about 0.000012 XRP.
Can a trust line let the issuer take my XRP?: No. The line only concerns that one token. What the issuer may be able to do is freeze or claw back its own token, if it set that up; the token safety guide shows how to check.
Why can’t I remove a trust line?: The line must be back to its default state: a zero balance and a zero limit. A tiny leftover balance is the usual cause; send it back to the issuer, then remove the line again.
Do I need a trust line for every token?: For every token issued with trust lines, yes, one per token. Multi-purpose tokens use a similar holder entry, and NFTs need none.