Cloudflare Workers AI on the free allowance
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Cloudflare Workers AI is the plugin's Cloudflare Workers AI provider:
Deepgram's Aura voices — 52 English speakers and 10 Spanish ones — and
MeloTTS, one voice each for English, Chinese, Japanese and Korean. Every
Cloudflare account, the free plan included, gets 10,000 Neurons of
inference a day at no charge, which is a few pages with an Aura voice or
hours of reading with MeloTTS. These voices highlight by sentence, not by
word. Time: about five minutes.
What you need
- A Cloudflare account — a free one is enough:
dash.cloudflare.com/sign-up. No
domain and no card is needed for the free allowance.
- Plugin 1.11.3 or newer.
1. Create a Workers AI token and copy the Account ID
- In the Cloudflare dashboard open AI →
Workers AI in the left column. A new account may be asked to enable
Workers first; that is free.
- Choose Use REST API.
- Press Create a Workers AI API Token, leave the prefilled token as it
is, Create API Token, then Copy API Token. The token is shown
once — paste it into the plugin right away, or keep it somewhere safe; a
lost one is simply replaced by a new one.
- The same page shows the Account ID under Get Account ID; copy it
too. It is also in the address of every dashboard page: the 32
characters after
dash.cloudflare.com/.
2. Put both into the plugin
Zotero → Settings → Zotero-TTS → Cloudflare Workers AI section:
| Account ID |
the 32-character id |
| API token |
the token |
Test connection should answer Connected. 66 voices available. Synthesis works. — the test lists the models, then synthesizes two letters, which
proves the account can spend. Enable locks the fields and adds the
voices. Open Read Aloud, choose the Local tier, and the Cloudflare-…
voices are there:
- under English, the Aura voices —
Cloudflare-Aura-2 Luna (female),
Cloudflare-Aura-1 Angus (male), … — and Cloudflare-MeloTTS English;
- under Spanish, the Aura-2 Spanish voices;
- under Chinese, Japanese and Korean, one MeloTTS voice each.
Which voice for what
- MeloTTS costs next to nothing: its four languages read all day within
the free allowance. One voice per language, plainer than Aura in English.
- Aura-1 is natural English at half of Aura-2's price: two or three
pages a day for free.
- Aura-2, English and Spanish, is Deepgram's best; the free allowance
is one or two pages a day.
- Every one of them is highlighted by sentence: none reports word timings.
For word-by-word highlighting use Azure, Kokoro or the Windows voices.
What the free allowance does and does not include
- 10,000 Neurons a day, on the free plan and the paid one alike, reset
daily. Neurons are Cloudflare's unit for inference, and each model's page
says what it costs in them. Measured on 2026-09-07: a 160-character
sentence is about 220 Neurons on Aura-1, twice that on Aura-2, and under 3
on MeloTTS. A day is therefore roughly 7,000 characters of Aura-1,
3,500 of Aura-2, or nine hours of MeloTTS.
- On the free plan, once the day's Neurons are spent, requests fail until
the next day — in the plugin the server refuses to synthesize and Read
Aloud stops. Nothing is charged.
- On the Workers Paid plan (US5amonth)readingcontinuespasttheallowanceatUS0.011 per 1,000 Neurons: a paper of 60,000 characters is
about a cent on MeloTTS, a dollar on Aura-1, two on Aura-2.
- The plugin synthesizes a few sentences ahead of playback, and on Aura a
sentence you skip past is still paid for. To spend less while jumping
around a document, lower Prefetch under Settings → Zotero-TTS →
Reading to 1.
- The day's usage is on the dashboard's Workers AI page.
Troubleshooting
- "The server rejected the API key … Authentication error": the token
or the Account ID is wrong — Cloudflare answers the same for both. Check
that the id has 32 characters and that the token was made on the Workers
AI page; a token made elsewhere may lack the Workers AI permission.
- "Cannot connect": no route to
api.cloudflare.com — a firewall or a
proxy; Zotero follows the system proxy settings.
- Synthesis worked this morning and fails now: the day's Neurons are
spent. Wait for the reset, or switch to a MeloTTS voice tomorrow.
- Aura reads only English or Spanish: that is what Aura speaks. A
document in another language wants a MeloTTS voice, or another provider.
- The Chinese voice reads English words too: MeloTTS's Chinese voice is
a mixed Chinese-and-English one by design.