How to switch ad networks without breaking your ads.txt
Add the new network's lines before removing the old ones, and leave both in place for a few days. Exchanges re-crawl ads.txt on their own schedule, so a line removed today can still be honoured tomorrow while a line added today is not yet honoured at all — and the overlap is what stops that gap costing you a week of revenue.
- Save a copy of the current file first. Before touching anything, keep the exact current contents somewhere you can find it. If the switch goes wrong, restoring the previous state is the fastest recovery and you will not reconstruct it from memory.
- Add the new lines, keep the old ones. Append rather than replace. Both networks authorised at once is a valid state, and it is the state that carries you through the changeover without a gap.
- Wait for the new network to confirm it sees them. Most networks verify your ads.txt during onboarding and will tell you when their lines are detected. Do not proceed on the assumption that publishing equals recognised.
- Only then remove the old lines. Once the new demand is live and earning, take the old entries out. If the new network is exclusive this step is required rather than optional, which is precisely why it must come last.
- Verify the final file parses. A managed network hands you a block of dozens of lines. A partial paste or one mangled line is invisible to you and silently drops that exchange.
The most common way a working ads.txt breaks
Theme updates get the blame, and they deserve some of it. But the single most
reliable way to end up with a broken ads.txt is a network switch — because
it is the one time you deliberately rewrite the file, usually in a hurry, often
by pasting a block someone emailed you.
Three things make it risky at once: the file changes substantially, the change
is manual, and it happens at a moment when you expect revenue to move anyway —
so the drop that follows a mistake is easily read as the new network settling in.
The lag runs in both directions
Publishers reason about ads.txt as though edits take effect immediately. They do
not. Exchanges fetch the file on their own schedules, typically daily.
That means:
- A line you remove today may still be honoured for another day
- A line you add today is not honoured until that exchange next crawls you
Replace the whole file in one edit and you create a window where the old
exchanges have noticed they are gone and the new ones have not yet noticed they
have arrived. Fewer bidders on every impression, for as long as the window
lasts, with nothing anywhere reporting a problem.
Add before you remove
The safe sequence is not complicated:
- Keep a copy of the current file exactly as it is
- Append the new network's lines, leaving the old ones in place
- Wait until the new network confirms it can see its entries
- Then remove the old lines
- Verify the final file still parses cleanly
Both networks authorised at the same time is a perfectly valid state. An ads.txt
declares who is allowed to sell your inventory; allowing two is not a conflict.
The only reason step 4 exists at all is that most managed networks are
exclusive — and that is exactly why it belongs at the end rather than the
beginning.
The exclusive-network trap
If your new network is exclusive — Mediavine,
Journey and Raptive all are — the
contract requires the old lines gone.
The mistake is doing that first, to be compliant, before the new setup is live.
That is the maximum-damage ordering: you have removed working demand and not yet
gained the replacement.
Get the new network live and earning, confirm it, then clean up. Every network
in this position understands a short overlap during migration; none of them
benefits from you having a bad week.
Verify the paste, not just the file
A managed network hands you a block of dozens of lines, mostly
RESELLER entries for exchanges you have
never heard of. Two things go wrong with a block that size:
A truncated line. One entry missing a field is discarded — that line only,
silently, while everything around it works. You lose one exchange and nothing
identifies which.
A partial paste. The block was longer than the clipboard selection, or the
editor wrapped a line, or the last entry lost its newline and merged into
whatever followed.
Neither is visible by looking at the file. Both are visible by
parsing it and counting the
entries against what you were sent.
If revenue drops after the switch
Check the file before you conclude the new network underperforms.
This matters because the wrong conclusion is expensive in both directions: you
either spend a month unhappy with a network that is fine, or you switch again
and repeat the same mistake. A dropped line during the paste is considerably
more common than a network being materially worse than advertised, and the two
produce an identical symptom.
The switch is also the moment when continuous
monitoring earns its keep most obviously — not because
the file is fragile in general, but because this is the week you touched it.
Frequently asked
- Why not just replace the file?
- Because removal takes effect on the exchange's crawl schedule, not yours. Replace the file today and the old exchanges stop bidding within a day, while the new ones may not have crawled you yet. That gap is a period with materially less demand and no error anywhere to explain it.
- Can two networks be in my ads.txt at once?
- Yes, and during a switch it is the correct state. An ads.txt authorises sellers; authorising two is not a conflict. The only reason to remove the old ones is an exclusivity requirement in your new contract.
- How long should the overlap last?
- A few days is usually enough for exchanges to re-crawl, but let the new network confirm it sees its lines rather than counting days. The cost of an extra week of overlap is nothing; the cost of removing too early is a week of thin auctions.
- My new network sent 40 lines. Is that normal?
- Yes. A managed network sells through many exchanges on your behalf, so their block is long and mostly RESELLER entries. Paste it exactly as given — this is the case where a single truncated line is easiest to miss.
- What if revenue drops after the switch anyway?
- Check the file first, before concluding the new network underperforms. A dropped line during the paste is far more common than a network being worse than advertised, and it produces exactly the same symptom.