Ask HN: Six-figure product end of road – sell customer-base?

Throwaway, but willing to reveal more if needed.

I've built a business out of a weekend-project over the past 4 years, which brought in six figures and is still growing.

My product helps businesses (and professionals) to market to certain channels, and my UVP is providing a self-service bridge to those channels. It requires quite a sophisticated technical effort to access those channels, and that's why only a few companies can offer it.

I have over 250 paying businesses on subscription (plans from $5 to $200 monthly), and many more on free tiers. It's enough for me to live off it, but not more.

Everything was sort of fine, until 'a new bridge appeared.'

A bridge built by those who assemble/control the target audience. And that bridge is only offered to be utilised by their exclusive partners -- which I am not, and won't be.

This means, for businesses, they will likely leave my platform eventually, and rather use one of the approved, exclusive partner products. My service still works, but using those exclusive products certainly feels a lot more professional -- and one day, may be the only viable route if those businesses want to use all the features.

My realistic options are: close down or hand over customers in some form of small-scale acquisition. But how? My service is bootstrapped, profitable, and without external investments or debts.

I don't have hard offers on the table, but a preliminary outreach resulted in 'some interest' to acquire users, possibly through some affiliate revenue share type of thing. The domain itself is probably worth more than that.

Would I go and cold-email (I am pretty sheltered off, contact-wise) those exclusive partners who seem to be a good fit, and warm up a potential customer hand-over to gauge interest? Most seem to be quite elaborate operations, and my potential user-base is probably like peanuts to them. I don't have a VC/accelerator network to utilise in getting the word out either.

Help!