FAQ
Everything about Inkli — from what the handwriting looks like to how partners integrate the engine into their fulfilment stack.
Inkli generates handwriting that is indistinguishable from real pen on paper. Every character is uniquely rendered with natural variation in size, slant, spacing, and ink density — no two letters are the same. Over 50 handwriting styles are available, each with real pen physics (pressure, bleed, pooling).
Handwriting fonts repeat identical glyphs, making them instantly recognisable as machine-generated. Inkli renders each character individually with per-stroke ink physics, pressure variation, and natural defects — the same way a real person writes.
It depends on the use case. If you're running a single campaign yourself, sign up free at inkli.app — 500 letters per month, no credit card required. If you're a mail house, agency, or print shop looking to integrate the engine into your fulfilment stack, talk to sales — you'll get keys, a dedicated pricing quote, and a technical walkthrough.
Yes. Inkli works like mail merge — upload a CSV of recipients and use variables like {{firstname}} and {{company}} in your message. Every letter is individually personalised and uniquely handwritten. Optional [[\r]] modifiers around a variable inject a line break only when the recipient has a value for that field — clean addresses that don't leave orphan blank lines.
Fountain pen, classic black, gel ink, red pen, green pen, and a growing catalogue of configurable ink presets. Every pen has distinct density, bleed, and texture characteristics. Partners can upload their own ICC profiles and configure custom shaders for brand-specific ink looks.
Yes — this is what the platform is built for. Direct mail houses render campaigns into the millions of letters through the API + delivery targets. Every letter is individually rendered with unique variation, even at scale.
For consumer plans: print-ready PDFs, downloadable in bulk. For platform partners: PDF/X-4 with ICC profile embedding, industry standards (FOGRA51, GRACoL, SWOP) or custom .icc uploads. Output includes bleed marks and trim boxes for finishing houses. Delivered to your SFTP, S3, or downloaded directly.
We render the artwork; you or your fulfilment partner print and post. That's deliberate — mail houses, print shops, and agencies use Inkli as the render engine underneath their existing fulfilment stack. If you don't have a mailing house already, we can connect you with partners who use Inkli.
Two paths. Consumer plans (self-serve) start free at 500 letters/month, with monthly tiers up to enterprise. Platform partners (mail houses, agencies, print shops) pay per letter in pence — from 3.5p per letter, dropping to 1.15p at 5M+/month. See the full rate card on the /platform page.
Encrypted at rest and in transit. Recipient data is used only for generating your letters and is never shared with third parties. Retention windows are configurable per partner — completed campaigns' recipients and output PDFs are purged on schedule, with billing tombstones preserved for audit. See our privacy policy for full details.
Yes — production REST API with pk_live_ / pk_test_ keys, per-actor Idempotency-Key support, and HMAC-signed webhooks. Full docs are shared on partner activation. Preview the surface at /developers.
Yes. Configure a delivery target on your account and the render fleet pushes output there instead of Inkli storage. SFTP (password or private-key auth) and S3-compatible endpoints both supported. Your customer never touches an Inkli download portal.
PDF/X-4 with your choice of embedded ICC profile — FOGRA51, GRACoL, SWOP, or upload a custom .icc. Bleed marks, trim boxes, and per-campaign colour overrides all supported. The format your Xerox iGen actually wants.
Yes, end-to-end. The output PDF has no Inkli branding. It arrives on your delivery target under your file naming. Your customer sees your invoice, your brand, your artwork — Inkli is invisible in the delivery path.
Every campaign supports an unmetered 3-recipient proof render. The output is watermarked "PROOF — NOT FOR USE" and never touches billing. Approve to fire the full render; reject to edit and re-proof. Fingerprint drift detection catches settings changes between proof and approval so you never approve a stale sample.
Standard limits are 60 rpm for reads and 10 rpm for writes with a brief +50% burst window. Higher limits available on request — enterprise partners get bespoke tiers. Response headers surface X-RateLimit-Remaining and X-RateLimit-Reset for clean back-off.
Per-partner retention window (e.g. 30/60/90 days) purges recipient data and output PDFs on schedule. Campaign metadata + billing tombstones stay for audit — you can prove what was sent without keeping the PII. Retention-deleted campaigns can still be duplicated (settings only) to run a fresh version.
No. Metering happens on successful completion only. A campaign that fails mid-render is never billed. Retry from the failed state does a clean idempotent reset and re-fires — no double charge, no partial charge.
Yes. Multi-tenant sub-client model — one partner account can host multiple end-client scopes, each with their own delivery target, usage rollup, and metering. Great for agencies running campaigns for multiple brands under one contract.
Keys are provisioned on partner activation. Two key formats: pk_live_ for production traffic and pk_test_ for unmetered CI + local dev. Mint, list, and revoke from the partner settings page. Idempotency-Key on writes lets you safely retry after a network wobble without creating duplicates.
Talk to sales if you're integrating, or sign up if you just want to try it.