Developer e-sign sandbox and free sends
Atlas gives developers five free envelope sends, API keys at signup, and draft creates without credit burn. Test webhooks and MCP before Stripe checkout.
Shaan F.
Co-founder & CEO, Atlas
On this page
Developers search for a free e-sign sandbox when they want to test create, send, webhooks, and signed PDF output before procurement talks. Atlas uses a single production API with a free send tier, not a separate hostname that behaves differently.
> Share: "Five free sends. Drafts free. Same API you ship to production."
What is free
| Action | Credits |
|---|---|
| Signup | 5 send credits granted |
| POST /api/envelope (draft) | 0 |
| Field detection | 0 |
| POST /api/envelope/{id}/send | 1 per envelope |
| MCP create (review only) | 0 until Send |
| Template send | 1 at dispatch |
Draft exploration does not burn credits. You pay when email goes out and Atlas does real delivery work.
Sandbox expectations
Atlas does not isolate tenants on sandbox.atlaswork.ai. Your test account uses the same endpoints:
https://atlaswork.ai/api/envelopehttps://atlaswork.ai/api/mcp
Use test signer emails you control. Signed PDFs and emails are real. Point webhook_url at ngrok or a Vercel preview with a stable tunnel.
Recommended test plan
- Create JSON with public test PDF URL at /signup after free account setup
- Poll
fields_statusuntil ready - Review open
review_url, adjust one field - Send to your inbox
- Sign on phone and desktop
- Webhook verify HMAC and payload shape
- Void a pending test envelope to see refund behavior when no one signed
Document envelope IDs in a scratch pad for support if something fails.
API keys
Generate keys in Dashboard → Settings after password signup. No sales call required. Keys are org-scoped when teams billing is enabled.
Rotate keys if you accidentally commit one. Never embed keys in client-side JavaScript.
MCP testing
Connect MCP from /mcp/cursor with the same key. Run through upload session flow for local PDF or DOCX.
Idempotency on MCP writes uses 60-second buckets. REST uses 24-hour Idempotency-Key header.
When you outgrow free sends
Buy credit packs in dashboard billing ($1 per envelope at list pricing). Stripe Checkout adds credits via webhook. No subscription required.
Envelope six and beyond needs credits or admin bypass for internal test accounts.
What Atlas is not
- Not unlimited free production traffic for your customers
- Not a separate weaker security tier for dev keys
- Not magic-link auth (password signup only)
Staging webhook tips
Use a dedicated webhook_url query param filter in your handler during dev. Log raw payload hashes to diff schema changes when Atlas adds optional fields. Tests should assert HMAC verification, not skip it for speed.
Common mistakes
Teams new to developer esign sandbox free often send before field detection finishes. Wait until fields_status is ready. If you hit 409, open review_url and check the banner.
Another miss: sharing a bare /sign/{id} link on multi-party deals. Each signer needs their token in the URL so they only see their fields.
Do not store API keys in frontend code or chat bot configs. Create envelopes from a server you control.
Staging checklist
Run one envelope to your own email before production traffic. Confirm webhook delivery, signed PDF download, and credit decrement match what finance expects.
Log create responses in structured JSON. When a signer says "I never got email," envelope ID finds the row faster than subject search.
If you use agents, document three approved prompts: create send, check status, remind signer. Wild prompts in live deal threads cause wrong-party sends.
When Atlas is the wrong tool
Atlas targets builders, agents, and usage-priced sends. If legal mandated DocuSign for every department, keep DocuSign for those flows and use Atlas where code creates the envelope.
If you need clickwrap on a marketing site with no review step, compare specialized clickwrap vendors. Atlas assumes a PDF or DOCX artifact and sequential signing.
Practical tips
Save envelope_id beside your CRM or ticket ID. Use metadata.client_reference_id on create so you can match webhooks back to your records.
Alert on 402 (out of credits) and 409 (fields still processing) in production jobs.
Train support to ask for envelope ID first. Subject lines lie.
Review credit burn monthly if you run seasonal bulk sends.
FAQ
Does Atlas accept PDF and DOCX?
Yes. Upload either format when you create an envelope. DOCX files become PDF before anyone signs.
How do I sign in?
Use a Bearer API key from your dashboard settings. MCP connectors in ChatGPT and Claude use OAuth instead.
When do credits get used?
One credit per send, not per upload. You get five free sends when you sign up.
Where should I start?
/docs and API reference.