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1contacts:
2 name: Tymek Chmielecki
3 title: SYSTEMS ENGINEER
4 email: me@timchmielecki.com
5 address: Krakow, PL
6 location: Poland
7 github:
8 url: https://github.com/timcki
9 displayText: "@timcki"
10 bluesky:
11 url: https://bsky.app/profile/tymek.me
12 displayText: "@tymek.me"
13 website:
14 url: https://timchmielecki.com
15 displayText: www.timchmielecki.com
16
17position: Systems Engineer
18
19tagline: Systems engineer with 6 years of professional experience. I have a strong background in blockchain, cryptography, and P2P networking. Looking for a challenging role in backend engineering, with an interest in developing decentralized systems and solving scaling problems.
20
21jobs:
22 - position: Systems Engineer
23 company:
24 name: TokenTax
25 link: "https://tokentax.co"
26 description:
27 - Joined as an early engineer and took ownership of the EVM data ingestion pipeline, operating and tuning full nodes for Ethereum, Polygon (Matic), BSC, etc., and iterating on how we index on-chain data for tax reporting
28 - Designed a wallet-centric sync pipeline using chain explorer APIs and batched checkpoints across all EVM chains, replacing our full-chain indexer, cutting storage by ~99% and increasing ingestion throughput ~3× while reliably syncing 2k+ wallets/day (up to 100k tx per wallet)
29 - Built an end-to-end regression harness that diffs per-wallet outputs between old and new pipelines, enabling a safe migration with no changes to user tax outcomes
30 - Became the main Go specialist on the accounting backend, ported the regression harness into the accounting service and then rewrote core internals to work around legacy design constraints, reducing memory usage by 60–70% while continuously verifying that user-level tax results remained identical
31 - Proposed and co-designed a new account-based data model for movements to align with updated IRS rules, then worked with the app backend team to implement it end-to-end (auto-labeling accounts across heterogeneous sources and computing per-account, day-by-day running balances)
32 - Since mid-2025, leading the entire syncing layer (not just EVM), sunsetting the legacy Go-based pipeline and porting protocol-specific parsing into the TypeScript codebase using a forked Goldrush decoder, while mentoring two junior engineers and reviewing PRs with a focus on data correctness and observability
33 from: "September 2021"
34 to: "Ongoing"
35 location: New York, USA (Remote)
36 - position: Backend and DevOps Engineer
37 company:
38 name: HID Global
39 link: "https://www.hidglobal.com"
40 description:
41 - "Proposed and built a software HSM: Go/cgo wrapper over a C++ crypto library, exposed as a secure network service and deployed in Docker on AWS Nitro Enclaves, providing a middle ground between hardware HSMs and an unsecured software process, plus contributions to smart-card auth based on Assa Abloy SEOS."
42 from: "June 2019"
43 to: "September 2021"
44 location: Krakow, PL
45 - position: Full-stack developer
46 company:
47 name: APCD Diffusion
48 link: ""
49 description:
50 - Built a Raspberry Pi IoT network for digital signage/advertising (Go backend, Bootstrap 4 UI, Python on devices).
51 format: "compact"
52 from: "Jan 2018"
53 to: "Jan 2019"
54 location: Paris, FR (Remote)
55 - position: Programming and Mathematics Tutor
56 company:
57 name: Freelance/Local groups
58 link: ""
59 description:
60 - Taught programming to kids aged 10-15; provided paid mathematics tutoring for middle/high school students.
61 format: "compact"
62 from: "2017"
63 to: "2021"
64 location: Krakow, PL
65
66projects:
67 - title: CryptoNote v2 Ring Signature Implementation
68 description: From-scratch implementation of the CryptoNote v2 ring-signature transaction scheme (basis of Monero) as bachelor thesis project, including stealth addresses, ring signatures, and key image generation for double-spend prevention.
69 technologies: Go, Cryptography
70 link: "https://github.com/timcki/learncoin"
71 - title: Ethereum Validator Node (Rocket Pool)
72 description: Operating and maintaining an Ethereum validator node using Rocket Pool protocol for decentralized staking.
73 technologies: Docker, Ethereum, Linux
74 link: ""
75
76skills:
77 - Ability to work independently and clearly define technical requirements
78 - P2P networking and decentralized systems
79 - Cryptography and cryptographic libraries
80 - Systems engineering and performance optimization
81
82languages:
83 - name: Polish
84 level: native
85 - name: French
86 level: native
87 - name: English
88 level: C2
89 - name: Spanish
90 level: A2
91 - name: Dutch
92 level: A1
93
94education:
95 - place:
96 name: AGH University of Science and Technology
97 link: ""
98 degree: B.S.
99 major: Computer Science
100 from: "09.2018"
101 to: "02.2022"
102 location: Krakow, PL