A net zero pledge means little until someone checks the evidence.
Cheltenham Zero works with Cheltenham Borough Council to move local businesses from supporting net zero to acting on it. That takes more than a sign-up page. A business has to learn, commit, submit evidence, and earn recognition, and the council has to verify that evidence before anyone is accredited.
PathZero is the platform behind that journey. Businesses register, programme staff approve them, and each one climbs five tiers from Member to Platinum. The work is a mix of training videos, short quizzes, signed declarations, data forms and document uploads. A council reviewer confirms every new tier.
None of it is public. Everything sits behind sign-in, because a platform like this holds far more than names and email addresses.
0.04g
CO₂e per PathZero sign-in page view, modelled
100
Lighthouse performance
121KB
page weight
Trust came before features.
Members are asked to hand their declarations, documents and emissions target years to their local council. If they can’t trust where that information goes, the programme doesn’t work.
So the brief began with constraints, not a feature list. Member data held apart from the design. Documents private by default. Staff access controlled and recorded.
Every later decision on Pathzero answered to those three.
01
Two parts, so the data outlives the design
Pathzero is a custom WordPress build in two halves. A plugin holds the data, the accreditation rules, the review screens and the security layer. A theme presents what the plugin gives it, and never reads the database directly.
That split is the decision the rest of the sustainable web development work rests on. The design can change, or be replaced entirely, without touching a member record or the rules that decide who is accredited.
The code stays plain for the same reason. No external code libraries, no frameworks, no build step. What’s written is what runs, which leaves fewer parts to keep up to date.
02
A journey members can follow and reviewers can check
Tasks unlock in order, so a member always knows what comes next. Anything that needs a human decision, such as an uploaded action plan, goes to a review queue rather than completing straight away. A reviewer approves it or sends it back with a note.
Programme staff get screens of their own: pending registrations, the review queue, a searchable member directory, an activity timeline for each member, and a journey builder for creating tasks and quizzes.
Members keep control of their own information. From their Settings page they can download their data, correct it or delete their account, with seven days to change their mind.
The privacy notice sets out the rest in plain terms. There are no analytics, advertising or tracking cookies, so there’s no cookie banner to click through.
We approached Agnikii Digital following a sustainability event. I knew they were the right fit to bring our platform to life, and we couldn't be happier!
03
Light at the door, looked after since launch
The sign-in page is where members start, so it carries very little. The PathZero sign-in page came in at about 121KB across seven files, with no web fonts and nothing from third-party servers, and scored 100 in all four Lighthouse categories.
Pages behind sign-in weren’t measured, and automated scores don’t replace a person testing with a keyboard or screen reader.
The platform is hosted with Agnikii Digital, which the Green Web Foundation lists as a green host.
Agnikii Digital maintains PathZero; now it’s live. WordPress and its plugins keep changing, and any change can bring weight or risk with it. Getting a platform light is one job. Keeping it that way is another.
Most common questions
01
What is PathZero?
A members-only net zero accreditation platform run by Cheltenham Zero in partnership with Cheltenham Borough Council.
02
How are tiers awarded?
A member completes every required task for the next tier, and a council reviewer checks the work and confirms it.
03
How is member data protected?
The privacy notice says documents are kept in private storage, every staff download is recorded and staff accounts must use two-factor authentication. It also says members can download a copy of their data or delete their account from their Settings page.
04
Why was it built as a plugin and a theme?
So member data and the accreditation rules sit apart from the design. The look can change without any risk to the records behind it.
05
Is the platform low-carbon?
The PathZero sign-in page models at 0.018g CO₂e per page view, about 121KB in all.