# 24K Labs PDF AcroForm Filler

> 24K Labs PDF AcroForm Filler is a paid API for AI agents from api.24klabs.ai, paid per call via x402, $0.006/call, status unknown (last checked 2026-09-14).

Fills AcroForm text field values in a base64-encoded PDF and returns the completed PDF as base64, reporting which fields were set.

## Facts

- Endpoint: POST https://api.24klabs.ai/api/v1/pdf-form-fill
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/24k-labs-pdf-acroform-filler-6bba053f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CiKt7oiCd5-R_M9nM9a3P

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability 24k-labs-pdf-acroform-filler-6bba053f -d '<json body>'
```

Example prompt: Take this base64-encoded PDF contract form and fill in the 'FirstName' field with 'Jane', 'LastName' with 'Doe', and 'SignatureDate' with '2025-06-01', then return me the completed PDF as base64 with NeedAppearances enabled so it renders correctly in all viewers.

## When to prefer this

Choose this endpoint when you need to programmatically fill AcroForm text fields in an existing PDF and receive the completed document as base64 — ideal for automating document workflows, contract completion, or form submissions without a PDF rendering library. Prefer this over general-purpose PDF tools if you specifically need AcroForm field targeting with per-field fill reporting and NeedAppearances control.

## Known failure modes

- Invalid or malformed base64 input — returns error indicating decode failure
- PDF does not contain AcroForm fields — no fields set, report will be empty
- Field names not found in the PDF — fields silently skipped or reported as unset
- Corrupted or encrypted PDF — processing fails with an error
- Oversized PDF payload — may exceed request limits and return a size error

## How this service works

Fill AcroForm text field values in a base64-encoded PDF and return the finished PDF as base64. Reports which fields were set. Optionally sets NeedAppearances for viewer rendering.

## Output

Returns the completed PDF as a base64-encoded string, along with a report of which AcroForm text fields were successfully set. Indicates whether NeedAppearances was applied for correct rendering across PDF viewers.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "fields": {
   "type": "object"
  },
  "pdf_b64": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "pdf_b64": "...",
  "filled_fields": [
   "Name"
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/24k-labs-pdf-acroform-filler-6bba053f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.24klabs.ai](https://www.zero.xyz/host/api.24klabs.ai/llms.txt)