The news will be a blow to the 2000 people on the bank's developer Slack channel who have invested time in building integration to the Monzo API.

"A startup’s most valuable resource is time and this year our focus is to launch current accounts," says CTO and co-founder Jonas Huckestein. "As a result, it is unlikely that we will be able to spend a lot of time on our public API work this year."

In the two years since it launched its first hackathon encouraging developers to build products using the API, the bank now counts some 100 personal projects integrating with the toolkit. Despite these efforts, Monzo will not allow developers to publish their current applications.

Huckestein now admits that the early iteration of the API was "full of leaky abstractions that don’t work well for current accounts" and that "we don't want other companies to rely on a product we cannot afford to support". The imminent arrival of PSD2 is another fly in the ointment which may change how banking APIs can be used, says Hucketestein. "We don’t want someone to build something amazing on our API to then have to be shut down because it doesn’t comply with the regulations."

As a result, he says, it's unlikely that Monzo will have a a full featured public API for at least the first few months after the launch of current accounts.

"We are still fully committed to our long-term strategy of building a banking platform that developers can easily integrate with," says Huckestein. "At some point next year, we hope to launch a public bank API and developer tools we’re truly proud of."

Ironically, the delays may leave the tech-led bank a bit behind the curve of some of the 'legacy' incumbents, who have been aggressively building out their own API strategies and developer portals over the course of the past year (check out the related stories tab for a sample).

Monzo isn't the only challenger waking up to the need to curtail its ambitions in favour of a more pragmatic approach. News has surfaced today that Tandem Bank has cut 30 of its staff, reducing the number of full-time employees from 110 to 80, following the sudden withdrawal of £29 million in promised funding earlier this year.