OpenAI 2026 hackathon

Signmos: Sign your PDF document as Human or as Agent

Signmos lets people and their AI agents prepare, send, sign, and recover PDFs without accounts, with email verification, audit trails, and a secure API

Solo project by Tomasz Kowalczyk · 0 likes · 0 comments

Archive position — measured, not model output

0 likes on Devpost

2,264 of the 7,856 archived projects have more likes, and 5,592 share exactly 0 — so this project's #6,706 place in the like-ranked listing is a tie-break inside that group, not a ranking.

Projects (log scale)

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Likes on Devpost. ▲ marks this project's group.

Show the figures
LikesProjectsShare of archive
05,59271.2%
11,75822.4%
22853.6%
3–41321.7%
5–9751.0%
10+140.2%
Devpost like counts for all 7,856 archived projects, captured when this archive was built.

Executive Summary

What the company appears to be

Signmos is a self-reported PDF e-signature tool designed for both human users and AI agents. The author describes it as an application that allows signing of PDF documents without requiring user accounts, using email verification, audit trails, and a secure API. It supports a browser-based workflow and an agentic mode where authorized agents can interact with the system via HTTP APIs.

What changed

The project was initially a browser-based MVP for PDF e-signatures. During OpenAI Build Week, it expanded to include agentic capabilities such as API token management, OpenAPI 3.1 documentation, agent operating guides, and improved authorization models for agents.

Single most important open question — the commercial due-diligence read

Is there any evidence of actual usage or adoption by humans or AI agents beyond the author’s own development work? The description contains no data on revenue, customers, or product-market fit.

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What The Product Actually Is

The description states that Signmos is a tool for signing PDF documents as either a human or an agent. It allows users to upload and prepare PDFs with signature and date fields, sign them, request changes, revise documents, resend, decline, or cancel agreements. Finalized PDFs are generated with audit trails. Access to documents is passwordless through "My Documents" access.

It also supports an “agentic mode” in which authorized agents can act on behalf of users using a documented REST API and OpenAPI 3.1 specification. Agents must use verified email addresses, and mutations require an Idempotency-Key. Authorization checks are performed against the user’s current creator or signer role.

The system is built with technologies including Cloudflare Workers, React, PostgreSQL, PDF-lib, and others.

Evidence

  • The author states: “Signmos lets people and their AI agents prepare, send, sign, and recover PDFs without accounts, with email verification, audit trails, and a secure API.”
  • It supports browser-based signing workflows.
  • Agentic mode is enabled via /api/v1, /agent.md, and /openapi.json.
  • The system uses token management, role checks, idempotency keys, and authorization models.

Inference The product appears to be a lightweight PDF e-signature platform with dual human-agent functionality. It does not appear to have a public-facing marketplace or third-party integrations beyond its own API.

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Positioning & Claim Evolution

The author claims Signmos is a tool for signing PDFs without accounts, using email verification and audit trails. It positions itself as a secure, lightweight solution that supports both human users and AI agents.

During OpenAI Build Week, the product evolved from a browser-based MVP to include agentic capabilities such as:

  • API token management
  • OpenAPI 3.1 documentation
  • Agent operating guide

The author notes that they used Codex and GPT-5.6 for planning and implementation, but the tool does not require an embedded LLM at runtime.

Evidence

  • The tagline: “Signmos lets people and their AI agents prepare, send, sign, and recover PDFs without accounts, with email verification, audit trails, and a secure API.”
  • The author states: “During the submission period, I was able to meaningfully extended it with: agentic mode landing-page workflow, personal API-token management, OpenAPI 3.1 documentation, agent operating guide.”

Inference The positioning has shifted from a simple browser-based e-signature tool to one that supports automation via APIs and AI agents. However, there is no evidence of how this evolved positioning was received by users or whether it reflects market demand.

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Target Customer & ICP

The description states that Signmos targets:

  • Individuals who want to sign PDFs without creating accounts.
  • AI agents that need to interact with the system programmatically via API.

It also mentions that the tool supports both self-signing and two-party agreements, suggesting a focus on personal or small business use cases.

Evidence

  • “no need an account (nobody likes setting accounts)”
  • “agentic mode which will allow automation in the future”
  • “easy PDF signing workflow for self-signing and two-party agreements”

Inference The ICP seems to be individuals seeking lightweight, account-free e-signature tools and developers or AI agents needing API access. No evidence of customer segmentation or user feedback is provided.

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Business Model & Pricing Evidence

There is no mention of pricing, monetization, or business model in the description. The author does not state whether Signmos charges for use, offers freemium tiers, or plans to introduce paid features.

Evidence

  • No reference to pricing.
  • No indication of revenue streams.
  • No statement about monetization strategy.

Inference The business model remains unknown. It is unclear if the tool will be free, subscription-based, or pay-per-use.

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Technical & Delivery Signals

Signmos is built using a modern tech stack including:

  • Cloudflare Workers
  • React
  • PostgreSQL
  • PDF-lib
  • TypeScript
  • TanStack Start, Router, Query, Form
  • Drizzle ORM
  • OpenAI Codex and GPT-5.6 for development assistance

The system supports API-based interaction with OpenAPI 3.1 documentation and includes features like:

  • Idempotency keys
  • Role-based access control
  • Token management
  • Bearer token authentication

Evidence

  • Built with: ai-agents, api-security, cloudflare-r2, cloudflare-turnstile, cloudflare-workers, drizzle-orm, electronic-signatures, gpt-5.6, hono, neon, openai-codex, openapi, pdf, pdf-lib, postgresql, react, resend, rest-api, tailwind-css, tanstack-form, tanstack-query, tanstack-router, tanstack-start, typescript, vitest
  • The author used Codex and GPT-5.6 for product planning and implementation.
  • API supports role checks, idempotency keys, and token-based authentication.

Inference The technical architecture suggests a modern, scalable, API-first approach with security in mind. However, no evidence of production deployment or performance data is available.

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Traction & Maturity Signals

There is no evidence of traction or adoption beyond the author’s own development work. No customer base, usage metrics, or user feedback are mentioned.

Evidence

  • The project was submitted to an OpenAI hackathon.
  • The author describes it as a browser-based MVP that evolved during Build Week.
  • No mention of users, customers, or product-market fit.

Inference The product is in early development and lacks any measurable traction. It has not yet reached a stage where user adoption or market validation can be assessed.

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Competitive Context

No competitive landscape or comparison to existing e-signature tools is provided in the description.

Evidence

  • No mention of competitors.
  • No reference to how Signmos differentiates from other PDF signing platforms.

Inference It is unclear whether Signmos competes with established players like DocuSign, PandaDoc, or HelloSign. The author does not position it within a competitive market.

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Key Risks & Red Flags

Key risks and red flags include:

  • No evidence of real-world usage or adoption.
  • No pricing or monetization strategy.
  • No customer feedback or user testing.
  • The product is described as self-developed by one person (team size: 1).
  • Lack of public-facing documentation or marketing materials.
  • No mention of security audits, compliance, or regulatory considerations.

Evidence

  • Team size: 1
  • No revenue, customers, or traction data
  • No mention of compliance or audit processes

Inference The lack of external validation and limited team size raise concerns about scalability and long-term viability. The absence of a monetization model also raises questions about sustainability.

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Diligence Questions To Ask The Founders

  1. What is the current usage rate of the tool by humans or agents?
  2. How many users are actively using the API, and what are their use cases?
  3. Are there any plans for monetization or pricing models?
  4. Has the authorization model been tested in real-world scenarios?
  5. What are the security measures in place beyond those described?
  6. Is there a plan to scale beyond one developer?
  7. How does Signmos intend to differentiate from existing e-signature platforms?

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Investment/Partnership Verdict

Not evidenced.

The description provides no data on revenue, customers, traction, or product-market fit. It is unclear whether Signmos has reached a stage where it could be considered for investment or partnership. The author’s own account suggests a functional MVP with some agentic capabilities, but there is no evidence of real-world adoption or commercial viability.

Evidence

  • No revenue data.
  • No customer base.
  • No traction metrics.
  • No indication of product-market fit.

Inference At this stage, Signmos appears to be an early-stage prototype with potential for future development. It lacks the commercial signals necessary for investment or partnership consideration.

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Source

Submitted to the OpenAI 2026 hackathon on Devpost. Project home on DevPost.

The analysis above was generated by a language model from the project's own one-line description. It is not independent research and contains no verified traction, revenue or customer data.