Convert EPUB to PDF Without Convertio Quota

If you hit Convertio's per-day conversion cap on EPUB or PDF work, you have two real options: pay for Convertio Premium ($9.99/mo with conversion-minute caps), or use a tool that's free for unlimited EPUB and PDF without daily limits. Convertio is a competent generalist — 200+ formats, OCR, browser extension. If your file work is exclusively EPUB and PDF, the math doesn't favour a generalist.

Where Convertio is the right pick

Multi-format work where EPUB is one of many things you touch. If you also convert HEIC photos, Office documents, audio files, and archive formats, the all-in-one workflow saves switching costs. The OCR is good. The format coverage is hard to match — there's no specialist that does everything Convertio does.

Use Convertio when: you process more than three different format families per week; you specifically need OCR on scanned PDFs; you've already paid for it.

Where Epublys is faster or cheaper

• EPUB-specific operations Convertio doesn't have. Validation against EPUB 2/3 spec with auto-fix, metadata editing (title/author/cover/series), splitting by chapter range, AI book cover generation. Convertio converts; it doesn't author or repair.
• No daily quota counter on free tier. Convertio's free tier has a per-day conversion limit and a "wait" countdown after a few files. Epublys free is 5 deliberate ops per day per IP plus unlimited reads/previews — designed around the working pattern of "fix one EPUB, move on" rather than throttling normal use.
• Pricing math. Epublys Pro is $9/month flat ($72/year) for unlimited EPUB/PDF work at 100MB files. Convertio Premium starts at $9.99/month with conversion-minute caps, and the unlimited tier is significantly more. For EPUB-only Pro, the math favours Epublys; for multi-format work it favours Convertio.
• Storage. Convertio retains uploaded files for 24 hours so you can re-download. Epublys never writes to disk — files are processed in-memory on a Cloudflare Worker and gone the moment the response returns. If your work involves manuscripts, NDA-bound material, or anything you'd rather not have sitting on a third-party server overnight, that's a real difference.

Quality of EPUB output

Convertio's EPUB↔PDF conversion is acceptable for casual use. For serious self-publishing, the quality differences show up at the edges: how chapters break, whether embedded fonts survive, whether the TOC structure is preserved correctly. Epublys is built around EPUB internals (OPF parsing, NAV documents, manifest integrity) — the conversion respects what a reader app expects to see. Run any converter's output through the validator before uploading to KDP or Apple Books.

API + agent access

Both expose a REST API. Epublys also ships an MCP server so AI agents (Claude Desktop, Cline, custom agents) can call the tools directly without integration code. Same Bearer API key works on both surfaces. Free tier API keys are available immediately at the account page; documentation lives at /openapi.json and /llms-full.txt.

Practical recommendation

If you opened this page because Convertio's quota or pricing is annoying you on EPUB work specifically: try the Epublys equivalent — EPUB to PDF, PDF to EPUB, or metadata editor — and see if the quality is enough. If you also need to convert WAV files and HEIC images, keep Convertio. The two tools coexist fine.

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